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Revision 1.259 by root, Tue Jul 28 02:07:18 2009 UTC vs.
Revision 1.364 by root, Mon Aug 15 12:56:53 2011 UTC

…		…
7		7
8	=head1 SYNOPSIS	8	=head1 SYNOPSIS
9		9
10	use AnyEvent;	10	use AnyEvent;
11		11
		12	# if you prefer function calls, look at the AE manpage for
		13	# an alternative API.
		14
12	# file descriptor readable	15	# file handle or descriptor readable
13	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });	16	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });
14		17
15	# one-shot or repeating timers	18	# one-shot or repeating timers
16	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });	19	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
17	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...	20	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...);
18		21
19	print AnyEvent->now; # prints current event loop time	22	print AnyEvent->now; # prints current event loop time
20	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.	23	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
21		24
22	# POSIX signal	25	# POSIX signal
…		…
43	in a tutorial or some gentle introduction, have a look at the	46	in a tutorial or some gentle introduction, have a look at the
44	L<AnyEvent::Intro> manpage.	47	L<AnyEvent::Intro> manpage.
45		48
46	=head1 SUPPORT	49	=head1 SUPPORT
47		50
		51	An FAQ document is available as L<AnyEvent::FAQ>.
		52
48	There is a mailinglist for discussing all things AnyEvent, and an IRC	53	There also is a mailinglist for discussing all things AnyEvent, and an IRC
49	channel, too.	54	channel, too.
50		55
51	See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software	56	See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software
52	Repository>, at L<http://anyevent.schmorp.de>, for more info.	57	Repository>, at L<http://anyevent.schmorp.de>, for more info.
53		58
…		…
73	module users into the same thing by forcing them to use the same event	78	module users into the same thing by forcing them to use the same event
74	model you use.	79	model you use.
75		80
76	For modules like POE or IO::Async (which is a total misnomer as it is	81	For modules like POE or IO::Async (which is a total misnomer as it is
77	actually doing all I/O I<synchronously>...), using them in your module is	82	actually doing all I/O I<synchronously>...), using them in your module is
78	like joining a cult: After you joined, you are dependent on them and you	83	like joining a cult: After you join, you are dependent on them and you
79	cannot use anything else, as they are simply incompatible to everything	84	cannot use anything else, as they are simply incompatible to everything
80	that isn't them. What's worse, all the potential users of your	85	that isn't them. What's worse, all the potential users of your
81	module are I<also> forced to use the same event loop you use.	86	module are I<also> forced to use the same event loop you use.
82		87
83	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works	88	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
84	fine. AnyEvent + Tk works fine etc. etc. but none of these work together	89	fine. AnyEvent + Tk works fine etc. etc. but none of these work together
85	with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if	90	with the rest: POE + EV? No go. Tk + Event? No go. Again: if your module
86	your module uses one of those, every user of your module has to use it,	91	uses one of those, every user of your module has to use it, too. But if
87	too. But if your module uses AnyEvent, it works transparently with all	92	your module uses AnyEvent, it works transparently with all event models it
88	event models it supports (including stuff like IO::Async, as long as those	93	supports (including stuff like IO::Async, as long as those use one of the
89	use one of the supported event loops. It is trivial to add new event loops	94	supported event loops. It is easy to add new event loops to AnyEvent, too,
90	to AnyEvent, too, so it is future-proof).	95	so it is future-proof).
91		96
92	In addition to being free of having to use I<the one and only true event	97	In addition to being free of having to use I<the one and only true event
93	model>, AnyEvent also is free of bloat and policy: with POE or similar	98	model>, AnyEvent also is free of bloat and policy: with POE or similar
94	modules, you get an enormous amount of code and strict rules you have to	99	modules, you get an enormous amount of code and strict rules you have to
95	follow. AnyEvent, on the other hand, is lean and up to the point, by only	100	follow. AnyEvent, on the other hand, is lean and to the point, by only
96	offering the functionality that is necessary, in as thin as a wrapper as	101	offering the functionality that is necessary, in as thin as a wrapper as
97	technically possible.	102	technically possible.
98		103
99	Of course, AnyEvent comes with a big (and fully optional!) toolbox	104	Of course, AnyEvent comes with a big (and fully optional!) toolbox
100	of useful functionality, such as an asynchronous DNS resolver, 100%	105	of useful functionality, such as an asynchronous DNS resolver, 100%
…		…
106	useful) and you want to force your users to use the one and only event	111	useful) and you want to force your users to use the one and only event
107	model, you should I<not> use this module.	112	model, you should I<not> use this module.
108		113
109	=head1 DESCRIPTION	114	=head1 DESCRIPTION
110		115
111	L<AnyEvent> provides an identical interface to multiple event loops. This	116	L<AnyEvent> provides a uniform interface to various event loops. This
112	allows module authors to utilise an event loop without forcing module	117	allows module authors to use event loop functionality without forcing
113	users to use the same event loop (as only a single event loop can coexist	118	module users to use a specific event loop implementation (since more
114	peacefully at any one time).	119	than one event loop cannot coexist peacefully).
115		120
116	The interface itself is vaguely similar, but not identical to the L<Event>	121	The interface itself is vaguely similar, but not identical to the L<Event>
117	module.	122	module.
118		123
119	During the first call of any watcher-creation method, the module tries	124	During the first call of any watcher-creation method, the module tries
120	to detect the currently loaded event loop by probing whether one of the	125	to detect the currently loaded event loop by probing whether one of the
121	following modules is already loaded: L<EV>,	126	following modules is already loaded: L<EV>, L<AnyEvent::Loop>,
122	L<Event>, L<Glib>, L<AnyEvent::Impl::Perl>, L<Tk>, L<Event::Lib>, L<Qt>,	127	L<Event>, L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. The first one
123	L<POE>. The first one found is used. If none are found, the module tries	128	found is used. If none are detected, the module tries to load the first
124	to load these modules (excluding Tk, Event::Lib, Qt and POE as the pure perl	129	four modules in the order given; but note that if L<EV> is not
125	adaptor should always succeed) in the order given. The first one that can	130	available, the pure-perl L<AnyEvent::Loop> should always work, so
126	be successfully loaded will be used. If, after this, still none could be	131	the other two are not normally tried.
127	found, AnyEvent will fall back to a pure-perl event loop, which is not
128	very efficient, but should work everywhere.
129		132
130	Because AnyEvent first checks for modules that are already loaded, loading	133	Because AnyEvent first checks for modules that are already loaded, loading
131	an event model explicitly before first using AnyEvent will likely make	134	an event model explicitly before first using AnyEvent will likely make
132	that model the default. For example:	135	that model the default. For example:
133		136
…		…
135	use AnyEvent;	138	use AnyEvent;
136		139
137	# .. AnyEvent will likely default to Tk	140	# .. AnyEvent will likely default to Tk
138		141
139	The I<likely> means that, if any module loads another event model and	142	The I<likely> means that, if any module loads another event model and
140	starts using it, all bets are off. Maybe you should tell their authors to	143	starts using it, all bets are off - this case should be very rare though,
141	use AnyEvent so their modules work together with others seamlessly...	144	as very few modules hardcode event loops without announcing this very
		145	loudly.
142		146
143	The pure-perl implementation of AnyEvent is called	147	The pure-perl implementation of AnyEvent is called C<AnyEvent::Loop>. Like
144	C<AnyEvent::Impl::Perl>. Like other event modules you can load it	148	other event modules you can load it explicitly and enjoy the high
145	explicitly and enjoy the high availability of that event loop :)	149	availability of that event loop :)
146		150
147	=head1 WATCHERS	151	=head1 WATCHERS
148		152
149	AnyEvent has the central concept of a I<watcher>, which is an object that	153	AnyEvent has the central concept of a I<watcher>, which is an object that
150	stores relevant data for each kind of event you are waiting for, such as	154	stores relevant data for each kind of event you are waiting for, such as
…		…
155	callback when the event occurs (of course, only when the event model	159	callback when the event occurs (of course, only when the event model
156	is in control).	160	is in control).
157		161
158	Note that B<callbacks must not permanently change global variables>	162	Note that B<callbacks must not permanently change global variables>
159	potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<	163	potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<
160	callbacks must not C<die> >>. The former is good programming practise in	164	callbacks must not C<die> >>. The former is good programming practice in
161	Perl and the latter stems from the fact that exception handling differs	165	Perl and the latter stems from the fact that exception handling differs
162	widely between event loops.	166	widely between event loops.
163		167
164	To disable the watcher you have to destroy it (e.g. by setting the	168	To disable a watcher you have to destroy it (e.g. by setting the
165	variable you store it in to C<undef> or otherwise deleting all references	169	variable you store it in to C<undef> or otherwise deleting all references
166	to it).	170	to it).
167		171
168	All watchers are created by calling a method on the C<AnyEvent> class.	172	All watchers are created by calling a method on the C<AnyEvent> class.
169		173
170	Many watchers either are used with "recursion" (repeating timers for	174	Many watchers either are used with "recursion" (repeating timers for
171	example), or need to refer to their watcher object in other ways.	175	example), or need to refer to their watcher object in other ways.
172		176
173	An any way to achieve that is this pattern:	177	One way to achieve that is this pattern:
174		178
175	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {	179	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
176	# you can use $w here, for example to undef it	180	# you can use $w here, for example to undef it
177	undef $w;	181	undef $w;
178	});	182	});
…		…
180	Note that C<my $w; $w => combination. This is necessary because in Perl,	184	Note that C<my $w; $w => combination. This is necessary because in Perl,
181	my variables are only visible after the statement in which they are	185	my variables are only visible after the statement in which they are
182	declared.	186	declared.
183		187
184	=head2 I/O WATCHERS	188	=head2 I/O WATCHERS
		189
		190	$w = AnyEvent->io (
		191	fh => <filehandle_or_fileno>,
		192	poll => <"r" or "w">,
		193	cb => <callback>,
		194	);
185		195
186	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	196	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
187	with the following mandatory key-value pairs as arguments:	197	with the following mandatory key-value pairs as arguments:
188		198
189	C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch	199	C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch
…		…
204		214
205	The I/O watcher might use the underlying file descriptor or a copy of it.	215	The I/O watcher might use the underlying file descriptor or a copy of it.
206	You must not close a file handle as long as any watcher is active on the	216	You must not close a file handle as long as any watcher is active on the
207	underlying file descriptor.	217	underlying file descriptor.
208		218
209	Some event loops issue spurious readyness notifications, so you should	219	Some event loops issue spurious readiness notifications, so you should
210	always use non-blocking calls when reading/writing from/to your file	220	always use non-blocking calls when reading/writing from/to your file
211	handles.	221	handles.
212		222
213	Example: wait for readability of STDIN, then read a line and disable the	223	Example: wait for readability of STDIN, then read a line and disable the
214	watcher.	224	watcher.
…		…
219	undef $w;	229	undef $w;
220	});	230	});
221		231
222	=head2 TIME WATCHERS	232	=head2 TIME WATCHERS
223		233
		234	$w = AnyEvent->timer (after => <seconds>, cb => <callback>);
		235
		236	$w = AnyEvent->timer (
		237	after => <fractional_seconds>,
		238	interval => <fractional_seconds>,
		239	cb => <callback>,
		240	);
		241
224	You can create a time watcher by calling the C<< AnyEvent->timer >>	242	You can create a time watcher by calling the C<< AnyEvent->timer >>
225	method with the following mandatory arguments:	243	method with the following mandatory arguments:
226		244
227	C<after> specifies after how many seconds (fractional values are	245	C<after> specifies after how many seconds (fractional values are
228	supported) the callback should be invoked. C<cb> is the callback to invoke	246	supported) the callback should be invoked. C<cb> is the callback to invoke
…		…
230		248
231	Although the callback might get passed parameters, their value and	249	Although the callback might get passed parameters, their value and
232	presence is undefined and you cannot rely on them. Portable AnyEvent	250	presence is undefined and you cannot rely on them. Portable AnyEvent
233	callbacks cannot use arguments passed to time watcher callbacks.	251	callbacks cannot use arguments passed to time watcher callbacks.
234		252
235	The callback will normally be invoked once only. If you specify another	253	The callback will normally be invoked only once. If you specify another
236	parameter, C<interval>, as a strictly positive number (> 0), then the	254	parameter, C<interval>, as a strictly positive number (> 0), then the
237	callback will be invoked regularly at that interval (in fractional	255	callback will be invoked regularly at that interval (in fractional
238	seconds) after the first invocation. If C<interval> is specified with a	256	seconds) after the first invocation. If C<interval> is specified with a
239	false value, then it is treated as if it were missing.	257	false value, then it is treated as if it were not specified at all.
240		258
241	The callback will be rescheduled before invoking the callback, but no	259	The callback will be rescheduled before invoking the callback, but no
242	attempt is done to avoid timer drift in most backends, so the interval is	260	attempt is made to avoid timer drift in most backends, so the interval is
243	only approximate.	261	only approximate.
244		262
245	Example: fire an event after 7.7 seconds.	263	Example: fire an event after 7.7 seconds.
246		264
247	my $w = AnyEvent->timer (after => 7.7, cb => sub {	265	my $w = AnyEvent->timer (after => 7.7, cb => sub {
…		…
265		283
266	While most event loops expect timers to specified in a relative way, they	284	While most event loops expect timers to specified in a relative way, they
267	use absolute time internally. This makes a difference when your clock	285	use absolute time internally. This makes a difference when your clock
268	"jumps", for example, when ntp decides to set your clock backwards from	286	"jumps", for example, when ntp decides to set your clock backwards from
269	the wrong date of 2014-01-01 to 2008-01-01, a watcher that is supposed to	287	the wrong date of 2014-01-01 to 2008-01-01, a watcher that is supposed to
270	fire "after" a second might actually take six years to finally fire.	288	fire "after a second" might actually take six years to finally fire.
271		289
272	AnyEvent cannot compensate for this. The only event loop that is conscious	290	AnyEvent cannot compensate for this. The only event loop that is conscious
273	about these issues is L<EV>, which offers both relative (ev_timer, based	291	of these issues is L<EV>, which offers both relative (ev_timer, based
274	on true relative time) and absolute (ev_periodic, based on wallclock time)	292	on true relative time) and absolute (ev_periodic, based on wallclock time)
275	timers.	293	timers.
276		294
277	AnyEvent always prefers relative timers, if available, matching the	295	AnyEvent always prefers relative timers, if available, matching the
278	AnyEvent API.	296	AnyEvent API.
…		…
300	I<In almost all cases (in all cases if you don't care), this is the	318	I<In almost all cases (in all cases if you don't care), this is the
301	function to call when you want to know the current time.>	319	function to call when you want to know the current time.>
302		320
303	This function is also often faster then C<< AnyEvent->time >>, and	321	This function is also often faster then C<< AnyEvent->time >>, and
304	thus the preferred method if you want some timestamp (for example,	322	thus the preferred method if you want some timestamp (for example,
305	L<AnyEvent::Handle> uses this to update it's activity timeouts).	323	L<AnyEvent::Handle> uses this to update its activity timeouts).
306		324
307	The rest of this section is only of relevance if you try to be very exact	325	The rest of this section is only of relevance if you try to be very exact
308	with your timing, you can skip it without bad conscience.	326	with your timing; you can skip it without a bad conscience.
309		327
310	For a practical example of when these times differ, consider L<Event::Lib>	328	For a practical example of when these times differ, consider L<Event::Lib>
311	and L<EV> and the following set-up:	329	and L<EV> and the following set-up:
312		330
313	The event loop is running and has just invoked one of your callback at	331	The event loop is running and has just invoked one of your callbacks at
314	time=500 (assume no other callbacks delay processing). In your callback,	332	time=500 (assume no other callbacks delay processing). In your callback,
315	you wait a second by executing C<sleep 1> (blocking the process for a	333	you wait a second by executing C<sleep 1> (blocking the process for a
316	second) and then (at time=501) you create a relative timer that fires	334	second) and then (at time=501) you create a relative timer that fires
317	after three seconds.	335	after three seconds.
318		336
…		…
338	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into	356	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
339	account.	357	account.
340		358
341	=item AnyEvent->now_update	359	=item AnyEvent->now_update
342		360
343	Some event loops (such as L<EV> or L<AnyEvent::Impl::Perl>) cache	361	Some event loops (such as L<EV> or L<AnyEvent::Loop>) cache the current
344	the current time for each loop iteration (see the discussion of L<<	362	time for each loop iteration (see the discussion of L<< AnyEvent->now >>,
345	AnyEvent->now >>, above).	363	above).
346		364
347	When a callback runs for a long time (or when the process sleeps), then	365	When a callback runs for a long time (or when the process sleeps), then
348	this "current" time will differ substantially from the real time, which	366	this "current" time will differ substantially from the real time, which
349	might affect timers and time-outs.	367	might affect timers and time-outs.
350		368
351	When this is the case, you can call this method, which will update the	369	When this is the case, you can call this method, which will update the
352	event loop's idea of "current time".	370	event loop's idea of "current time".
353		371
		372	A typical example would be a script in a web server (e.g. C<mod_perl>) -
		373	when mod_perl executes the script, then the event loop will have the wrong
		374	idea about the "current time" (being potentially far in the past, when the
		375	script ran the last time). In that case you should arrange a call to C<<
		376	AnyEvent->now_update >> each time the web server process wakes up again
		377	(e.g. at the start of your script, or in a handler).
		378
354	Note that updating the time I<might> cause some events to be handled.	379	Note that updating the time I<might> cause some events to be handled.
355		380
356	=back	381	=back
357		382
358	=head2 SIGNAL WATCHERS	383	=head2 SIGNAL WATCHERS
		384
		385	$w = AnyEvent->signal (signal => <uppercase_signal_name>, cb => <callback>);
359		386
360	You can watch for signals using a signal watcher, C<signal> is the signal	387	You can watch for signals using a signal watcher, C<signal> is the signal
361	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl	388	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
362	callback to be invoked whenever a signal occurs.	389	callback to be invoked whenever a signal occurs.
363		390
…		…
380		407
381	Example: exit on SIGINT	408	Example: exit on SIGINT
382		409
383	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });	410	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
384		411
		412	=head3 Restart Behaviour
		413
		414	While restart behaviour is up to the event loop implementation, most will
		415	not restart syscalls (that includes L<Async::Interrupt> and AnyEvent's
		416	pure perl implementation).
		417
		418	=head3 Safe/Unsafe Signals
		419
		420	Perl signals can be either "safe" (synchronous to opcode handling) or
		421	"unsafe" (asynchronous) - the former might get delayed indefinitely, the
		422	latter might corrupt your memory.
		423
		424	AnyEvent signal handlers are, in addition, synchronous to the event loop,
		425	i.e. they will not interrupt your running perl program but will only be
		426	called as part of the normal event handling (just like timer, I/O etc.
		427	callbacks, too).
		428
385	=head3 Signal Races, Delays and Workarounds	429	=head3 Signal Races, Delays and Workarounds
386		430
387	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching	431	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
388	callbacks to signals in a generic way, which is a pity, as you cannot do	432	callbacks to signals in a generic way, which is a pity, as you cannot
389	race-free signal handling in perl. AnyEvent will try to do it's best, but	433	do race-free signal handling in perl, requiring C libraries for
		434	this. AnyEvent will try to do its best, which means in some cases,
390	in some cases, signals will be delayed. The maximum time a signal might	435	signals will be delayed. The maximum time a signal might be delayed is
391	be delayed is specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10	436	specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This
392	seconds). This variable can be changed only before the first signal	437	variable can be changed only before the first signal watcher is created,
393	watcher is created, and should be left alone otherwise. Higher values	438	and should be left alone otherwise. This variable determines how often
		439	AnyEvent polls for signals (in case a wake-up was missed). Higher values
394	will cause fewer spurious wake-ups, which is better for power and CPU	440	will cause fewer spurious wake-ups, which is better for power and CPU
		441	saving.
		442
395	saving. All these problems can be avoided by installing the optional	443	All these problems can be avoided by installing the optional
396	L<Async::Interrupt> module. This will not work with inherently broken	444	L<Async::Interrupt> module, which works with most event loops. It will not
397	event loops such as L<Event> or L<Event::Lib> (and not with L<POE>	445	work with inherently broken event loops such as L<Event> or L<Event::Lib>
398	currently, as POE does it's own workaround with one-second latency). With	446	(and not with L<POE> currently, as POE does its own workaround with
399	those, you just have to suffer the delays.	447	one-second latency). For those, you just have to suffer the delays.
400		448
401	=head2 CHILD PROCESS WATCHERS	449	=head2 CHILD PROCESS WATCHERS
402		450
		451	$w = AnyEvent->child (pid => <process id>, cb => <callback>);
		452
403	You can also watch on a child process exit and catch its exit status.	453	You can also watch for a child process exit and catch its exit status.
404		454
405	The child process is specified by the C<pid> argument (one some backends,	455	The child process is specified by the C<pid> argument (on some backends,
406	using C<0> watches for any child process exit, on others this will	456	using C<0> watches for any child process exit, on others this will
407	croak). The watcher will be triggered only when the child process has	457	croak). The watcher will be triggered only when the child process has
408	finished and an exit status is available, not on any trace events	458	finished and an exit status is available, not on any trace events
409	(stopped/continued).	459	(stopped/continued).
410		460
…		…
432	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
433	watcher before you C<fork> the child (alternatively, you can call	483	watcher before you C<fork> the child (alternatively, you can call
434	C<AnyEvent::detect>).	484	C<AnyEvent::detect>).
435		485
436	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
437	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
438	mentioned in the description of signal watchers apply.	488	problems mentioned in the description of signal watchers apply.
439		489
440	Example: fork a process and wait for it	490	Example: fork a process and wait for it
441		491
442	my $done = AnyEvent->condvar;	492	my $done = AnyEvent->condvar;
443		493
…		…
455	# do something else, then wait for process exit	505	# do something else, then wait for process exit
456	$done->recv;	506	$done->recv;
457		507
458	=head2 IDLE WATCHERS	508	=head2 IDLE WATCHERS
459		509
460	Sometimes there is a need to do something, but it is not so important	510	$w = AnyEvent->idle (cb => <callback>);
461	to do it instantly, but only when there is nothing better to do. This
462	"nothing better to do" is usually defined to be "no other events need
463	attention by the event loop".
464		511
465	Idle watchers ideally get invoked when the event loop has nothing	512	This will repeatedly invoke the callback after the process becomes idle,
466	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.
467	events. Instead of blocking, the idle watcher is invoked.
468		514
469	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
470	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
471	will simply call the callback "from time to time".	526	will simply call the callback "from time to time".
472		527
473	Example: read lines from STDIN, but only process them when the	528	Example: read lines from STDIN, but only process them when the
474	program is otherwise idle:	529	program is otherwise idle:
…		…
490	});	545	});
491	});	546	});
492		547
493	=head2 CONDITION VARIABLES	548	=head2 CONDITION VARIABLES
494		549
		550	$cv = AnyEvent->condvar;
		551
		552	$cv->send (<list>);
		553	my @res = $cv->recv;
		554
495	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
496	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
497	will actively watch for new events and call your callbacks.	557	will actively watch for new events and call your callbacks.
498		558
499	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
500	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).
501		561
502	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
503	because they represent a condition that must become true.	563	they represent a condition that must become true.
504		564
505	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.
506		566
507	Condition variables can be created by calling the C<< AnyEvent->condvar	567	Condition variables can be created by calling the C<< AnyEvent->condvar
508	>> method, usually without arguments. The only argument pair allowed is	568	>> method, usually without arguments. The only argument pair allowed is
…		…
513	After creation, the condition variable is "false" until it becomes "true"	573	After creation, the condition variable is "false" until it becomes "true"
514	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
515	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<<
516	->send >> method).	576	->send >> method).
517		577
518	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
519	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:
520	in time where multiple outstanding events have been processed. And yet	580
521	another way to call them is transactions - each condition variable can be	581	=over 4
522	used to represent a transaction, which finishes at some point and delivers	582
523	a result. And yet some people know them as "futures" - a promise to	583	=item * Condition variables are like callbacks - you can call them (and pass them instead
524	compute/deliver something that you can wait for.	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
525		601
526	Condition variables are very useful to signal that something has finished,	602	Condition variables are very useful to signal that something has finished,
527	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,
528	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
529	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
…		…
542		618
543	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
544	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
545	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
546	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
547	it's C<new> method in your own C<new> method.	623	its C<new> method in your own C<new> method.
548		624
549	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
550	eventually calls C<< -> send >>, and the "consumer side", which waits	626	eventually calls C<< -> send >>, and the "consumer side", which waits
551	for the send to occur.	627	for the send to occur.
552		628
553	Example: wait for a timer.	629	Example: wait for a timer.
554		630
555	# wait till the result is ready	631	# condition: "wait till the timer is fired"
556	my $result_ready = AnyEvent->condvar;	632	my $timer_fired = AnyEvent->condvar;
557		633
558	# do something such as adding a timer	634	# create the timer - we could wait for, say
559	# or socket watcher the calls $result_ready->send	635	# a handle becomign ready, or even an
560	# when the "result" is ready.	636	# AnyEvent::HTTP request to finish, but
561	# in this case, we simply use a timer:	637	# in this case, we simply use a timer:
562	my $w = AnyEvent->timer (	638	my $w = AnyEvent->timer (
563	after => 1,	639	after => 1,
564	cb => sub { $result_ready->send },	640	cb => sub { $timer_fired->send },
565	);	641	);
566		642
567	# this "blocks" (while handling events) till the callback	643	# this "blocks" (while handling events) till the callback
568	# calls -<send	644	# calls ->send
569	$result_ready->recv;	645	$timer_fired->recv;
570		646
571	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
572	variables are also callable directly.	648	variables are also callable directly.
573		649
574	my $done = AnyEvent->condvar;	650	my $done = AnyEvent->condvar;
…		…
617	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
618	C<send>.	694	C<send>.
619		695
620	=item $cv->croak ($error)	696	=item $cv->croak ($error)
621		697
622	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
623	C<Carp::croak> with the given error message/object/scalar.	699	C<Carp::croak> with the given error message/object/scalar.
624		700
625	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
626	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
627	delays the error detetcion, but has the overwhelmign advantage that it	703	delays the error detection, but has the overwhelming advantage that it
628	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
629	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
630	the problem.	706	the problem.
631		707
632	=item $cv->begin ([group callback])	708	=item $cv->begin ([group callback])
633		709
634	=item $cv->end	710	=item $cv->end
…		…
637	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
638	to use a condition variable for the whole process.	714	to use a condition variable for the whole process.
639		715
640	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
641	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
642	>>, 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
643	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
644	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.
645		722
646	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
647	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
648	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).
649		726
…		…
671	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
672	sending.	749	sending.
673		750
674	The ping example mentioned above is slightly more complicated, as the	751	The ping example mentioned above is slightly more complicated, as the
675	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
676	begung can potentially be zero:	753	begun can potentially be zero:
677		754
678	my $cv = AnyEvent->condvar;	755	my $cv = AnyEvent->condvar;
679		756
680	my %result;	757	my %result;
681	$cv->begin (sub { $cv->send (\%result) });	758	$cv->begin (sub { shift->send (\%result) });
682		759
683	for my $host (@list_of_hosts) {	760	for my $host (@list_of_hosts) {
684	$cv->begin;	761	$cv->begin;
685	ping_host_then_call_callback $host, sub {	762	ping_host_then_call_callback $host, sub {
686	$result{$host} = ...;	763	$result{$host} = ...;
…		…
702	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
703	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
704	doesn't execute once).	781	doesn't execute once).
705		782
706	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
707	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
708	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
709	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,
710	call C<end>.	787	call C<end>.
711		788
712	=back	789	=back
…		…
719	=over 4	796	=over 4
720		797
721	=item $cv->recv	798	=item $cv->recv
722		799
723	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak	800	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
724	>> methods have been called on c<$cv>, while servicing other watchers	801	>> methods have been called on C<$cv>, while servicing other watchers
725	normally.	802	normally.
726		803
727	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
728	will return immediately.	805	will return immediately.
729		806
…		…
746	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
747	condition variables with some kind of request results and supporting	824	condition variables with some kind of request results and supporting
748	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,
749	while still supporting blocking waits if the caller so desires).	826	while still supporting blocking waits if the caller so desires).
750		827
751	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
752	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
753	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
754	waits otherwise.	831	waits otherwise.
755		832
756	=item $bool = $cv->ready	833	=item $bool = $cv->ready
…		…
762		839
763	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
764	replaces it before doing so.	841	replaces it before doing so.
765		842
766	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
767	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
768	variable itself. Calling C<recv> inside the callback or at any later time	845	condition variable itself. If the condition is already true, the
769	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.
770		848
771	=back	849	=back
772		850
773	=head1 SUPPORTED EVENT LOOPS/BACKENDS	851	=head1 SUPPORTED EVENT LOOPS/BACKENDS
774		852
…		…
777	=over 4	855	=over 4
778		856
779	=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.
780		858
781	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
782	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
783	that, will fall back to its own pure-perl implementation, which is	861	pure-perl implementation, which is available everywhere as it comes with
784	available everywhere as it comes with AnyEvent itself.	862	AnyEvent itself.
785		863
786	AnyEvent::Impl::EV based on EV (interface to libev, best choice).	864	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
787	AnyEvent::Impl::Event based on Event, very stable, few glitches.
788	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.	865	AnyEvent::Impl::Perl pure-perl AnyEvent::Loop, fast and portable.
789		866
790	=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.
791		868
792	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
793	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
794	them. This means that AnyEvent will automatically pick the right backend	871	them. This means that AnyEvent will automatically pick the right backend
795	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
796	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.
797		874
		875	AnyEvent::Impl::Event based on Event, very stable, few glitches.
798	AnyEvent::Impl::Glib based on Glib, slow but very stable.	876	AnyEvent::Impl::Glib based on Glib, slow but very stable.
799	AnyEvent::Impl::Tk based on Tk, very broken.	877	AnyEvent::Impl::Tk based on Tk, very broken.
800	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.	878	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
801	AnyEvent::Impl::POE based on POE, very slow, some limitations.	879	AnyEvent::Impl::POE based on POE, very slow, some limitations.
802	AnyEvent::Impl::Irssi used when running within irssi.	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).
803		884
804	=item Backends with special needs.	885	=item Backends with special needs.
805		886
806	Qt requires the Qt::Application to be instantiated first, but will	887	Qt requires the Qt::Application to be instantiated first, but will
807	otherwise be picked up automatically. As long as the main program	888	otherwise be picked up automatically. As long as the main program
808	instantiates the application before any AnyEvent watchers are created,	889	instantiates the application before any AnyEvent watchers are created,
809	everything should just work.	890	everything should just work.
810		891
811	AnyEvent::Impl::Qt based on Qt.	892	AnyEvent::Impl::Qt based on Qt.
812		893
813	Support for IO::Async can only be partial, as it is too broken and
814	architecturally limited to even support the AnyEvent API. It also
815	is the only event loop that needs the loop to be set explicitly, so
816	it can only be used by a main program knowing about AnyEvent. See
817	L<AnyEvent::Impl::Async> for the gory details.
818
819	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
820
821	=item Event loops that are indirectly supported via other backends.	894	=item Event loops that are indirectly supported via other backends.
822		895
823	Some event loops can be supported via other modules:	896	Some event loops can be supported via other modules:
824		897
825	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>.
…		…
850	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
851	backend has been autodetected.	924	backend has been autodetected.
852		925
853	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
854	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
855	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
856	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
857	will be C<urxvt::anyevent>).	930	will be C<urxvt::anyevent>).
858		931
859	=item AnyEvent::detect	932	=item AnyEvent::detect
860		933
861	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	934	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
862	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
863	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
864	runtime, and not e.g. while initialising of your module.	937	runtime, and not e.g. during initialisation of your module.
		938
		939	The effect of calling this function is as if a watcher had been created
		940	(specifically, actions that happen "when the first watcher is created"
		941	happen when calling detetc as well).
865		942
866	If you need to do some initialisation before AnyEvent watchers are	943	If you need to do some initialisation before AnyEvent watchers are
867	created, use C<post_detect>.	944	created, use C<post_detect>.
868		945
869	=item $guard = AnyEvent::post_detect { BLOCK }	946	=item $guard = AnyEvent::post_detect { BLOCK }
870		947
871	Arranges for the code block to be executed as soon as the event model is	948	Arranges for the code block to be executed as soon as the event model is
872	autodetected (or immediately if this has already happened).	949	autodetected (or immediately if that has already happened).
873		950
874	The block will be executed I<after> the actual backend has been detected	951	The block will be executed I<after> the actual backend has been detected
875	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been	952	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
876	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do	953	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
877	other initialisations - see the sources of L<AnyEvent::Strict> or	954	other initialisations - see the sources of L<AnyEvent::Strict> or
…		…
886	that automatically removes the callback again when it is destroyed (or	963	that automatically removes the callback again when it is destroyed (or
887	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for	964	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
888	a case where this is useful.	965	a case where this is useful.
889		966
890	Example: Create a watcher for the IO::AIO module and store it in	967	Example: Create a watcher for the IO::AIO module and store it in
891	C<$WATCHER>. Only do so after the event loop is initialised, though.	968	C<$WATCHER>, but do so only do so after the event loop is initialised.
892		969
893	our WATCHER;	970	our WATCHER;
894		971
895	my $guard = AnyEvent::post_detect {	972	my $guard = AnyEvent::post_detect {
896	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);	973	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
…		…
904	$WATCHER ||= $guard;	981	$WATCHER ||= $guard;
905		982
906	=item @AnyEvent::post_detect	983	=item @AnyEvent::post_detect
907		984
908	If there are any code references in this array (you can C<push> to it	985	If there are any code references in this array (you can C<push> to it
909	before or after loading AnyEvent), then they will called directly after	986	before or after loading AnyEvent), then they will be called directly
910	the event loop has been chosen.	987	after the event loop has been chosen.
911		988
912	You should check C<$AnyEvent::MODEL> before adding to this array, though:	989	You should check C<$AnyEvent::MODEL> before adding to this array, though:
913	if it is defined then the event loop has already been detected, and the	990	if it is defined then the event loop has already been detected, and the
914	array will be ignored.	991	array will be ignored.
915		992
916	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows	993	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
917	it,as it takes care of these details.	994	it, as it takes care of these details.
918		995
919	This variable is mainly useful for modules that can do something useful	996	This variable is mainly useful for modules that can do something useful
920	when AnyEvent is used and thus want to know when it is initialised, but do	997	when AnyEvent is used and thus want to know when it is initialised, but do
921	not need to even load it by default. This array provides the means to hook	998	not need to even load it by default. This array provides the means to hook
922	into AnyEvent passively, without loading it.	999	into AnyEvent passively, without loading it.
923		1000
		1001	Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used
		1002	together, you could put this into Coro (this is the actual code used by
		1003	Coro to accomplish this):
		1004
		1005	if (defined $AnyEvent::MODEL) {
		1006	# AnyEvent already initialised, so load Coro::AnyEvent
		1007	require Coro::AnyEvent;
		1008	} else {
		1009	# AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
		1010	# as soon as it is
		1011	push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
		1012	}
		1013
		1014	=item AnyEvent::postpone { BLOCK }
		1015
		1016	Arranges for the block to be executed as soon as possible, but not before
		1017	the call itself returns. In practise, the block will be executed just
		1018	before the event loop polls for new events, or shortly afterwards.
		1019
		1020	This function never returns anything (to make the C<return postpone { ...
		1021	}> idiom more useful.
		1022
		1023	To understand the usefulness of this function, consider a function that
		1024	asynchronously does something for you and returns some transaction
		1025	object or guard to let you cancel the operation. For example,
		1026	C<AnyEvent::Socket::tcp_connect>:
		1027
		1028	# start a conenction attempt unless one is active
		1029	$self->{connect_guard} ||= AnyEvent::Socket::tcp_connect "www.example.net", 80, sub {
		1030	delete $self->{connect_guard};
		1031	...
		1032	};
		1033
		1034	Imagine that this function could instantly call the callback, for
		1035	example, because it detects an obvious error such as a negative port
		1036	number. Invoking the callback before the function returns causes problems
		1037	however: the callback will be called and will try to delete the guard
		1038	object. But since the function hasn't returned yet, there is nothing to
		1039	delete. When the function eventually returns it will assign the guard
		1040	object to C<< $self->{connect_guard} >>, where it will likely never be
		1041	deleted, so the program thinks it is still trying to connect.
		1042
		1043	This is where C<AnyEvent::postpone> should be used. Instead of calling the
		1044	callback directly on error:
		1045
		1046	$cb->(undef), return # signal error to callback, BAD!
		1047	if $some_error_condition;
		1048
		1049	It should use C<postpone>:
		1050
		1051	AnyEvent::postpone { $cb->(undef) }, return # signal error to callback, later
		1052	if $some_error_condition;
		1053
924	=back	1054	=back
925		1055
926	=head1 WHAT TO DO IN A MODULE	1056	=head1 WHAT TO DO IN A MODULE
927		1057
928	As a module author, you should C<use AnyEvent> and call AnyEvent methods	1058	As a module author, you should C<use AnyEvent> and call AnyEvent methods
…		…
938	because it will stall the whole program, and the whole point of using	1068	because it will stall the whole program, and the whole point of using
939	events is to stay interactive.	1069	events is to stay interactive.
940		1070
941	It is fine, however, to call C<< ->recv >> when the user of your module	1071	It is fine, however, to call C<< ->recv >> when the user of your module
942	requests it (i.e. if you create a http request object ad have a method	1072	requests it (i.e. if you create a http request object ad have a method
943	called C<results> that returns the results, it should call C<< ->recv >>	1073	called C<results> that returns the results, it may call C<< ->recv >>
944	freely, as the user of your module knows what she is doing. always).	1074	freely, as the user of your module knows what she is doing. Always).
945		1075
946	=head1 WHAT TO DO IN THE MAIN PROGRAM	1076	=head1 WHAT TO DO IN THE MAIN PROGRAM
947		1077
948	There will always be a single main program - the only place that should	1078	There will always be a single main program - the only place that should
949	dictate which event model to use.	1079	dictate which event model to use.
950		1080
951	If it doesn't care, it can just "use AnyEvent" and use it itself, or not	1081	If the program is not event-based, it need not do anything special, even
952	do anything special (it does not need to be event-based) and let AnyEvent	1082	when it depends on a module that uses an AnyEvent. If the program itself
953	decide which implementation to chose if some module relies on it.	1083	uses AnyEvent, but does not care which event loop is used, all it needs
		1084	to do is C<use AnyEvent>. In either case, AnyEvent will choose the best
		1085	available loop implementation.
954		1086
955	If the main program relies on a specific event model - for example, in	1087	If the main program relies on a specific event model - for example, in
956	Gtk2 programs you have to rely on the Glib module - you should load the	1088	Gtk2 programs you have to rely on the Glib module - you should load the
957	event module before loading AnyEvent or any module that uses it: generally	1089	event module before loading AnyEvent or any module that uses it: generally
958	speaking, you should load it as early as possible. The reason is that	1090	speaking, you should load it as early as possible. The reason is that
959	modules might create watchers when they are loaded, and AnyEvent will	1091	modules might create watchers when they are loaded, and AnyEvent will
960	decide on the event model to use as soon as it creates watchers, and it	1092	decide on the event model to use as soon as it creates watchers, and it
961	might chose the wrong one unless you load the correct one yourself.	1093	might choose the wrong one unless you load the correct one yourself.
962		1094
963	You can chose to use a pure-perl implementation by loading the	1095	You can chose to use a pure-perl implementation by loading the
964	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour	1096	C<AnyEvent::Loop> module, which gives you similar behaviour
965	everywhere, but letting AnyEvent chose the model is generally better.	1097	everywhere, but letting AnyEvent chose the model is generally better.
966		1098
967	=head2 MAINLOOP EMULATION	1099	=head2 MAINLOOP EMULATION
968		1100
969	Sometimes (often for short test scripts, or even standalone programs who	1101	Sometimes (often for short test scripts, or even standalone programs who
…		…
984	=head1 OTHER MODULES	1116	=head1 OTHER MODULES
985		1117
986	The following is a non-exhaustive list of additional modules that use	1118	The following is a non-exhaustive list of additional modules that use
987	AnyEvent as a client and can therefore be mixed easily with other AnyEvent	1119	AnyEvent as a client and can therefore be mixed easily with other AnyEvent
988	modules and other event loops in the same program. Some of the modules	1120	modules and other event loops in the same program. Some of the modules
989	come with AnyEvent, most are available via CPAN.	1121	come as part of AnyEvent, the others are available via CPAN.
990		1122
991	=over 4	1123	=over 4
992		1124
993	=item L<AnyEvent::Util>	1125	=item L<AnyEvent::Util>
994		1126
995	Contains various utility functions that replace often-used but blocking	1127	Contains various utility functions that replace often-used blocking
996	functions such as C<inet_aton> by event-/callback-based versions.	1128	functions such as C<inet_aton> with event/callback-based versions.
997		1129
998	=item L<AnyEvent::Socket>	1130	=item L<AnyEvent::Socket>
999		1131
1000	Provides various utility functions for (internet protocol) sockets,	1132	Provides various utility functions for (internet protocol) sockets,
1001	addresses and name resolution. Also functions to create non-blocking tcp	1133	addresses and name resolution. Also functions to create non-blocking tcp
…		…
1003		1135
1004	=item L<AnyEvent::Handle>	1136	=item L<AnyEvent::Handle>
1005		1137
1006	Provide read and write buffers, manages watchers for reads and writes,	1138	Provide read and write buffers, manages watchers for reads and writes,
1007	supports raw and formatted I/O, I/O queued and fully transparent and	1139	supports raw and formatted I/O, I/O queued and fully transparent and
1008	non-blocking SSL/TLS (via L<AnyEvent::TLS>.	1140	non-blocking SSL/TLS (via L<AnyEvent::TLS>).
1009		1141
1010	=item L<AnyEvent::DNS>	1142	=item L<AnyEvent::DNS>
1011		1143
1012	Provides rich asynchronous DNS resolver capabilities.	1144	Provides rich asynchronous DNS resolver capabilities.
1013		1145
		1146	=item L<AnyEvent::HTTP>, L<AnyEvent::IRC>, L<AnyEvent::XMPP>, L<AnyEvent::GPSD>, L<AnyEvent::IGS>, L<AnyEvent::FCP>
		1147
		1148	Implement event-based interfaces to the protocols of the same name (for
		1149	the curious, IGS is the International Go Server and FCP is the Freenet
		1150	Client Protocol).
		1151
		1152	=item L<AnyEvent::Handle::UDP>
		1153
		1154	Here be danger!
		1155
		1156	As Pauli would put it, "Not only is it not right, it's not even wrong!" -
		1157	there are so many things wrong with AnyEvent::Handle::UDP, most notably
		1158	its use of a stream-based API with a protocol that isn't streamable, that
		1159	the only way to improve it is to delete it.
		1160
		1161	It features data corruption (but typically only under load) and general
		1162	confusion. On top, the author is not only clueless about UDP but also
		1163	fact-resistant - some gems of his understanding: "connect doesn't work
		1164	with UDP", "UDP packets are not IP packets", "UDP only has datagrams, not
		1165	packets", "I don't need to implement proper error checking as UDP doesn't
		1166	support error checking" and so on - he doesn't even understand what's
		1167	wrong with his module when it is explained to him.
		1168
1014	=item L<AnyEvent::HTTP>	1169	=item L<AnyEvent::DBI>
1015		1170
1016	A simple-to-use HTTP library that is capable of making a lot of concurrent	1171	Executes L<DBI> requests asynchronously in a proxy process for you,
1017	HTTP requests.	1172	notifying you in an event-based way when the operation is finished.
		1173
		1174	=item L<AnyEvent::AIO>
		1175
		1176	Truly asynchronous (as opposed to non-blocking) I/O, should be in the
		1177	toolbox of every event programmer. AnyEvent::AIO transparently fuses
		1178	L<IO::AIO> and AnyEvent together, giving AnyEvent access to event-based
		1179	file I/O, and much more.
1018		1180
1019	=item L<AnyEvent::HTTPD>	1181	=item L<AnyEvent::HTTPD>
1020		1182
1021	Provides a simple web application server framework.	1183	A simple embedded webserver.
1022		1184
1023	=item L<AnyEvent::FastPing>	1185	=item L<AnyEvent::FastPing>
1024		1186
1025	The fastest ping in the west.	1187	The fastest ping in the west.
1026
1027	=item L<AnyEvent::DBI>
1028
1029	Executes L<DBI> requests asynchronously in a proxy process.
1030
1031	=item L<AnyEvent::AIO>
1032
1033	Truly asynchronous I/O, should be in the toolbox of every event
1034	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
1035	together.
1036
1037	=item L<AnyEvent::BDB>
1038
1039	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
1040	L<BDB> and AnyEvent together.
1041
1042	=item L<AnyEvent::GPSD>
1043
1044	A non-blocking interface to gpsd, a daemon delivering GPS information.
1045
1046	=item L<AnyEvent::IRC>
1047
1048	AnyEvent based IRC client module family (replacing the older Net::IRC3).
1049
1050	=item L<AnyEvent::XMPP>
1051
1052	AnyEvent based XMPP (Jabber protocol) module family (replacing the older
1053	Net::XMPP2>.
1054
1055	=item L<AnyEvent::IGS>
1056
1057	A non-blocking interface to the Internet Go Server protocol (used by
1058	L<App::IGS>).
1059
1060	=item L<Net::FCP>
1061
1062	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
1063	of AnyEvent.
1064
1065	=item L<Event::ExecFlow>
1066
1067	High level API for event-based execution flow control.
1068		1188
1069	=item L<Coro>	1189	=item L<Coro>
1070		1190
1071	Has special support for AnyEvent via L<Coro::AnyEvent>.	1191	Has special support for AnyEvent via L<Coro::AnyEvent>.
1072		1192
…		…
1076		1196
1077	package AnyEvent;	1197	package AnyEvent;
1078		1198
1079	# basically a tuned-down version of common::sense	1199	# basically a tuned-down version of common::sense
1080	sub common_sense {	1200	sub common_sense {
1081	# no warnings	1201	# from common:.sense 3.4
1082	${^WARNING_BITS} ^= ${^WARNING_BITS};	1202	${^WARNING_BITS} ^= ${^WARNING_BITS} ^ "\x3c\x3f\x33\x00\x0f\xf0\x0f\xc0\xf0\xfc\x33\x00";
1083	# use strict vars subs	1203	# use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)
1084	$^H |= 0x00000600;	1204	$^H |= 0x00000600;
1085	}	1205	}
1086		1206
1087	BEGIN { AnyEvent::common_sense }	1207	BEGIN { AnyEvent::common_sense }
1088		1208
1089	use Carp ();	1209	use Carp ();
1090		1210
1091	our $VERSION = 4.88;	1211	our $VERSION = '6.01';
1092	our $MODEL;	1212	our $MODEL;
1093		1213
1094	our $AUTOLOAD;
1095	our @ISA;	1214	our @ISA;
1096		1215
1097	our @REGISTRY;	1216	our @REGISTRY;
1098		1217
1099	our $WIN32;
1100
1101	our $VERBOSE;	1218	our $VERBOSE;
1102		1219
1103	BEGIN {	1220	BEGIN {
1104	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";	1221	require "AnyEvent/constants.pl";
		1222
1105	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";	1223	eval "sub TAINT (){" . (${^TAINT}*1) . "}";
1106		1224
1107	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}	1225	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
1108	if ${^TAINT};	1226	if ${^TAINT};
1109		1227
1110	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1228	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
…		…
1120	$PROTOCOL{$_} = ++$idx	1238	$PROTOCOL{$_} = ++$idx
1121	for reverse split /\s*,\s*/,	1239	for reverse split /\s*,\s*/,
1122	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1240	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
1123	}	1241	}
1124		1242
		1243	our @post_detect;
		1244
		1245	sub post_detect(&) {
		1246	my ($cb) = @_;
		1247
		1248	push @post_detect, $cb;
		1249
		1250	defined wantarray
		1251	? bless \$cb, "AnyEvent::Util::postdetect"
		1252	: ()
		1253	}
		1254
		1255	sub AnyEvent::Util::postdetect::DESTROY {
		1256	@post_detect = grep $_ != ${$_[0]}, @post_detect;
		1257	}
		1258
		1259	our $POSTPONE_W;
		1260	our @POSTPONE;
		1261
		1262	sub _postpone_exec {
		1263	undef $POSTPONE_W;
		1264
		1265	&{ shift @POSTPONE }
		1266	while @POSTPONE;
		1267	}
		1268
		1269	sub postpone(&) {
		1270	push @POSTPONE, shift;
		1271
		1272	$POSTPONE_W ||= AE::timer (0, 0, \&_postpone_exec);
		1273
		1274	()
		1275	}
		1276
1125	my @models = (	1277	our @models = (
1126	[EV:: => AnyEvent::Impl::EV:: , 1],	1278	[EV:: => AnyEvent::Impl::EV:: , 1],
		1279	[AnyEvent::Loop:: => AnyEvent::Impl::Perl:: , 1],
		1280	# everything below here will not (normally) be autoprobed
		1281	# as the pure perl backend should work everywhere
		1282	# and is usually faster
1127	[Event:: => AnyEvent::Impl::Event::, 1],	1283	[Event:: => AnyEvent::Impl::Event::, 1],
1128	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],
1129	# everything below here will not (normally) be autoprobed
1130	# as the pureperl backend should work everywhere
1131	# and is usually faster
1132	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers	1284	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
1133	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	1285	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
1134	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package	1286	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
1135	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1287	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
1136	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1288	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
1137	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1289	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
1138	[Wx:: => AnyEvent::Impl::POE::],	1290	[Wx:: => AnyEvent::Impl::POE::],
1139	[Prima:: => AnyEvent::Impl::POE::],	1291	[Prima:: => AnyEvent::Impl::POE::],
1140	# IO::Async is just too broken - we would need workarounds for its	1292	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # a bitch to autodetect
1141	# byzantine signal and broken child handling, among others.	1293	[Cocoa::EventLoop:: => AnyEvent::Impl::Cocoa::],
1142	# IO::Async is rather hard to detect, as it doesn't have any	1294	[FLTK:: => AnyEvent::Impl::FLTK2::],
1143	# obvious default class.
1144	# [0, IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
1145	# [0, IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
1146	# [0, IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
1147	);	1295	);
1148		1296
1149	our %method = map +($_ => 1),	1297	our @isa_hook;
		1298
		1299	sub _isa_set {
		1300	my @pkg = ("AnyEvent", (map $_->[0], grep defined, @isa_hook), $MODEL);
		1301
		1302	@{"$pkg[$_-1]::ISA"} = $pkg[$_]
		1303	for 1 .. $#pkg;
		1304
		1305	grep $_ && $_->[1], @isa_hook
		1306	and AE::_reset ();
		1307	}
		1308
		1309	# used for hooking AnyEvent::Strict and AnyEvent::Debug::Wrap into the class hierarchy
		1310	sub _isa_hook($$;$) {
		1311	my ($i, $pkg, $reset_ae) = @_;
		1312
		1313	$isa_hook[$i] = $pkg ? [$pkg, $reset_ae] : undef;
		1314
		1315	_isa_set;
		1316	}
		1317
		1318	# all autoloaded methods reserve the complete glob, not just the method slot.
		1319	# due to bugs in perls method cache implementation.
1150	qw(io timer time now now_update signal child idle condvar one_event DESTROY);	1320	our @methods = qw(io timer time now now_update signal child idle condvar);
1151		1321
1152	our @post_detect;
1153
1154	sub post_detect(&) {	1322	sub detect() {
1155	my ($cb) = @_;	1323	return $MODEL if $MODEL; # some programs keep references to detect
1156		1324
1157	if ($MODEL) {	1325	local $!; # for good measure
1158	$cb->();	1326	local $SIG{__DIE__}; # we use eval
1159		1327
1160	undef	1328	# free some memory
		1329	*detect = sub () { $MODEL };
		1330	# undef &func doesn't correctly update the method cache. grmbl.
		1331	# so we delete the whole glob. grmbl.
		1332	# otoh, perl doesn't let me undef an active usb, but it lets me free
		1333	# a glob with an active sub. hrm. i hope it works, but perl is
		1334	# usually buggy in this department. sigh.
		1335	delete @{"AnyEvent::"}{@methods};
		1336	undef @methods;
		1337
		1338	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z0-9:]+)$/) {
		1339	my $model = $1;
		1340	$model = "AnyEvent::Impl::$model" unless $model =~ s/::$//;
		1341	if (eval "require $model") {
		1342	$MODEL = $model;
		1343	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
1161	} else {	1344	} else {
1162	push @post_detect, $cb;	1345	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
1163		1346	}
1164	defined wantarray
1165	? bless \$cb, "AnyEvent::Util::postdetect"
1166	: ()
1167	}	1347	}
1168	}
1169		1348
1170	sub AnyEvent::Util::postdetect::DESTROY {	1349	# check for already loaded models
1171	@post_detect = grep $_ != ${$_[0]}, @post_detect;
1172	}
1173
1174	sub detect() {
1175	unless ($MODEL) {	1350	unless ($MODEL) {
1176	local $SIG{__DIE__};	1351	for (@REGISTRY, @models) {
1177		1352	my ($package, $model) = @$_;
1178	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	1353	if (${"$package\::VERSION"} > 0) {
1179	my $model = "AnyEvent::Impl::$1";
1180	if (eval "require $model") {	1354	if (eval "require $model") {
1181	$MODEL = $model;	1355	$MODEL = $model;
1182	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;	1356	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1183	} else {	1357	last;
1184	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;	1358	}
1185	}	1359	}
1186	}	1360	}
1187		1361
1188	# check for already loaded models
1189	unless ($MODEL) {	1362	unless ($MODEL) {
		1363	# try to autoload a model
1190	for (@REGISTRY, @models) {	1364	for (@REGISTRY, @models) {
1191	my ($package, $model) = @$_;	1365	my ($package, $model, $autoload) = @$_;
		1366	if (
		1367	$autoload
		1368	and eval "require $package"
1192	if (${"$package\::VERSION"} > 0) {	1369	and ${"$package\::VERSION"} > 0
1193	if (eval "require $model") {	1370	and eval "require $model"
		1371	) {
1194	$MODEL = $model;	1372	$MODEL = $model;
1195	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;	1373	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
1196	last;	1374	last;
1197	}
1198	}	1375	}
1199	}	1376	}
1200		1377
1201	unless ($MODEL) {
1202	# try to autoload a model
1203	for (@REGISTRY, @models) {
1204	my ($package, $model, $autoload) = @$_;
1205	if (
1206	$autoload
1207	and eval "require $package"
1208	and ${"$package\::VERSION"} > 0
1209	and eval "require $model"
1210	) {
1211	$MODEL = $model;
1212	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
1213	last;
1214	}
1215	}
1216
1217	$MODEL	1378	$MODEL
1218	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";	1379	or die "AnyEvent: backend autodetection failed - did you properly install AnyEvent?\n";
1219	}
1220	}	1380	}
1221
1222	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1223
1224	unshift @ISA, $MODEL;
1225
1226	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
1227
1228	(shift @post_detect)->() while @post_detect;
1229	}	1381	}
1230		1382
		1383	# free memory only needed for probing
		1384	undef @models;
		1385	undef @REGISTRY;
		1386
		1387	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1388
		1389	# now nuke some methods that are overridden by the backend.
		1390	# SUPER usage is not allowed in these.
		1391	for (qw(time signal child idle)) {
		1392	undef &{"AnyEvent::Base::$_"}
		1393	if defined &{"$MODEL\::$_"};
		1394	}
		1395
		1396	_isa_set;
		1397
		1398	if ($ENV{PERL_ANYEVENT_STRICT}) {
		1399	require AnyEvent::Strict;
		1400	}
		1401
		1402	if ($ENV{PERL_ANYEVENT_DEBUG_WRAP}) {
		1403	require AnyEvent::Debug;
		1404	AnyEvent::Debug::wrap ($ENV{PERL_ANYEVENT_DEBUG_WRAP});
		1405	}
		1406
		1407	if (exists $ENV{PERL_ANYEVENT_DEBUG_SHELL}) {
		1408	require AnyEvent::Socket;
		1409	require AnyEvent::Debug;
		1410
		1411	my $shell = $ENV{PERL_ANYEVENT_DEBUG_SHELL};
		1412	$shell =~ s/\$\$/$$/g;
		1413
		1414	my ($host, $service) = AnyEvent::Socket::parse_hostport ($shell);
		1415	$AnyEvent::Debug::SHELL = AnyEvent::Debug::shell ($host, $service);
		1416	}
		1417
		1418	(shift @post_detect)->() while @post_detect;
		1419	undef @post_detect;
		1420
		1421	*post_detect = sub(&) {
		1422	shift->();
		1423
		1424	undef
		1425	};
		1426
1231	$MODEL	1427	$MODEL
1232	}	1428	}
1233		1429
1234	sub AUTOLOAD {	1430	for my $name (@methods) {
1235	(my $func = $AUTOLOAD) =~ s/.*://;	1431	*$name = sub {
1236		1432	detect;
1237	$method{$func}	1433	# we use goto because
1238	or Carp::croak "$func: not a valid method for AnyEvent objects";	1434	# a) it makes the thunk more transparent
1239		1435	# b) it allows us to delete the thunk later
1240	detect unless $MODEL;	1436	goto &{ UNIVERSAL::can AnyEvent => "SUPER::$name" }
1241		1437	};
1242	my $class = shift;
1243	$class->$func (@_);
1244	}	1438	}
1245		1439
1246	# utility function to dup a filehandle. this is used by many backends	1440	# utility function to dup a filehandle. this is used by many backends
1247	# to support binding more than one watcher per filehandle (they usually	1441	# to support binding more than one watcher per filehandle (they usually
1248	# allow only one watcher per fd, so we dup it to get a different one).	1442	# allow only one watcher per fd, so we dup it to get a different one).
…		…
1258	# we assume CLOEXEC is already set by perl in all important cases	1452	# we assume CLOEXEC is already set by perl in all important cases
1259		1453
1260	($fh2, $rw)	1454	($fh2, $rw)
1261	}	1455	}
1262		1456
		1457	=head1 SIMPLIFIED AE API
		1458
		1459	Starting with version 5.0, AnyEvent officially supports a second, much
		1460	simpler, API that is designed to reduce the calling, typing and memory
		1461	overhead by using function call syntax and a fixed number of parameters.
		1462
		1463	See the L<AE> manpage for details.
		1464
		1465	=cut
		1466
		1467	package AE;
		1468
		1469	our $VERSION = $AnyEvent::VERSION;
		1470
		1471	sub _reset() {
		1472	eval q{
		1473	# fall back to the main API by default - backends and AnyEvent::Base
		1474	# implementations can overwrite these.
		1475
		1476	sub io($$$) {
		1477	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
		1478	}
		1479
		1480	sub timer($$$) {
		1481	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
		1482	}
		1483
		1484	sub signal($$) {
		1485	AnyEvent->signal (signal => $_[0], cb => $_[1])
		1486	}
		1487
		1488	sub child($$) {
		1489	AnyEvent->child (pid => $_[0], cb => $_[1])
		1490	}
		1491
		1492	sub idle($) {
		1493	AnyEvent->idle (cb => $_[0]);
		1494	}
		1495
		1496	sub cv(;&) {
		1497	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
		1498	}
		1499
		1500	sub now() {
		1501	AnyEvent->now
		1502	}
		1503
		1504	sub now_update() {
		1505	AnyEvent->now_update
		1506	}
		1507
		1508	sub time() {
		1509	AnyEvent->time
		1510	}
		1511
		1512	*postpone = \&AnyEvent::postpone;
		1513	};
		1514	die if $@;
		1515	}
		1516
		1517	BEGIN { _reset }
		1518
1263	package AnyEvent::Base;	1519	package AnyEvent::Base;
1264		1520
1265	# default implementations for many methods	1521	# default implementations for many methods
1266		1522
1267	sub _time {	1523	sub time {
		1524	eval q{ # poor man's autoloading {}
1268	# probe for availability of Time::HiRes	1525	# probe for availability of Time::HiRes
1269	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {	1526	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
1270	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;	1527	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
		1528	*time = sub { Time::HiRes::time () };
1271	*_time = \&Time::HiRes::time;	1529	*AE::time = \& Time::HiRes::time ;
1272	# if (eval "use POSIX (); (POSIX::times())...	1530	# if (eval "use POSIX (); (POSIX::times())...
1273	} else {	1531	} else {
1274	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;	1532	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1275	*_time = sub { time }; # epic fail	1533	*time = sub { CORE::time };
		1534	*AE::time = sub (){ CORE::time };
		1535	}
		1536
		1537	*now = \&time;
1276	}	1538	};
		1539	die if $@;
1277		1540
1278	&_time	1541	&time
1279	}	1542	}
1280		1543
1281	sub time { _time }	1544	*now = \&time;
1282	sub now { _time }
1283	sub now_update { }	1545	sub now_update { }
1284		1546
		1547	sub _poll {
		1548	Carp::croak "$AnyEvent::MODEL does not support blocking waits. Caught";
		1549	}
		1550
1285	# default implementation for ->condvar	1551	# default implementation for ->condvar
		1552	# in fact, the default should not be overwritten
1286		1553
1287	sub condvar {	1554	sub condvar {
		1555	eval q{ # poor man's autoloading {}
		1556	*condvar = sub {
1288	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"	1557	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
		1558	};
		1559
		1560	*AE::cv = sub (;&) {
		1561	bless { @_ ? (_ae_cb => shift) : () }, "AnyEvent::CondVar"
		1562	};
		1563	};
		1564	die if $@;
		1565
		1566	&condvar
1289	}	1567	}
1290		1568
1291	# default implementation for ->signal	1569	# default implementation for ->signal
1292		1570
1293	our $HAVE_ASYNC_INTERRUPT;	1571	our $HAVE_ASYNC_INTERRUPT;
		1572
		1573	sub _have_async_interrupt() {
		1574	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
		1575	&& eval "use Async::Interrupt 1.02 (); 1")
		1576	unless defined $HAVE_ASYNC_INTERRUPT;
		1577
		1578	$HAVE_ASYNC_INTERRUPT
		1579	}
		1580
1294	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1581	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
1295	our (%SIG_ASY, %SIG_ASY_W);	1582	our (%SIG_ASY, %SIG_ASY_W);
1296	our ($SIG_COUNT, $SIG_TW);	1583	our ($SIG_COUNT, $SIG_TW);
1297		1584
1298	sub _signal_exec {
1299	$HAVE_ASYNC_INTERRUPT
1300	? $SIGPIPE_R->drain
1301	: sysread $SIGPIPE_R, my $dummy, 9;
1302
1303	while (%SIG_EV) {
1304	for (keys %SIG_EV) {
1305	delete $SIG_EV{$_};
1306	$_->() for values %{ $SIG_CB{$_} || {} };
1307	}
1308	}
1309	}
1310
1311	# install a dumym wakeupw atcher to reduce signal catching latency	1585	# install a dummy wakeup watcher to reduce signal catching latency
		1586	# used by Impls
1312	sub _sig_add() {	1587	sub _sig_add() {
1313	unless ($SIG_COUNT++) {	1588	unless ($SIG_COUNT++) {
1314	# try to align timer on a full-second boundary, if possible	1589	# try to align timer on a full-second boundary, if possible
1315	my $NOW = AnyEvent->now;	1590	my $NOW = AE::now;
1316		1591
1317	$SIG_TW = AnyEvent->timer (	1592	$SIG_TW = AE::timer
1318	after => $MAX_SIGNAL_LATENCY - ($NOW - int $NOW),	1593	$MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
1319	interval => $MAX_SIGNAL_LATENCY,	1594	$MAX_SIGNAL_LATENCY,
1320	cb => sub { }, # just for the PERL_ASYNC_CHECK	1595	sub { } # just for the PERL_ASYNC_CHECK
1321	);	1596	;
1322	}	1597	}
1323	}	1598	}
1324		1599
1325	sub _sig_del {	1600	sub _sig_del {
1326	undef $SIG_TW	1601	undef $SIG_TW
1327	unless --$SIG_COUNT;	1602	unless --$SIG_COUNT;
1328	}	1603	}
1329		1604
		1605	our $_sig_name_init; $_sig_name_init = sub {
		1606	eval q{ # poor man's autoloading {}
		1607	undef $_sig_name_init;
		1608
		1609	if (_have_async_interrupt) {
		1610	*sig2num = \&Async::Interrupt::sig2num;
		1611	*sig2name = \&Async::Interrupt::sig2name;
		1612	} else {
		1613	require Config;
		1614
		1615	my %signame2num;
		1616	@signame2num{ split ' ', $Config::Config{sig_name} }
		1617	= split ' ', $Config::Config{sig_num};
		1618
		1619	my @signum2name;
		1620	@signum2name[values %signame2num] = keys %signame2num;
		1621
		1622	*sig2num = sub($) {
		1623	$_[0] > 0 ? shift : $signame2num{+shift}
		1624	};
		1625	*sig2name = sub ($) {
		1626	$_[0] > 0 ? $signum2name[+shift] : shift
		1627	};
		1628	}
		1629	};
		1630	die if $@;
		1631	};
		1632
		1633	sub sig2num ($) { &$_sig_name_init; &sig2num }
		1634	sub sig2name($) { &$_sig_name_init; &sig2name }
		1635
1330	sub _signal {	1636	sub signal {
1331	my (undef, %arg) = @_;	1637	eval q{ # poor man's autoloading {}
		1638	# probe for availability of Async::Interrupt
		1639	if (_have_async_interrupt) {
		1640	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1332		1641
1333	my $signal = uc $arg{signal}	1642	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1334	or Carp::croak "required option 'signal' is missing";	1643	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1335		1644
1336	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1645	} else {
		1646	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
1337		1647
1338	if ($HAVE_ASYNC_INTERRUPT) {	1648	if (AnyEvent::WIN32) {
1339	# async::interrupt	1649	require AnyEvent::Util;
1340		1650
1341	$SIG_ASY{$signal} ||= do {	1651	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1342	my $asy = new Async::Interrupt	1652	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
1343	cb => sub { undef $SIG_EV{$signal} },	1653	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
1344	signal => $signal,	1654	} else {
1345	pipe => [$SIGPIPE_R->filenos],	1655	pipe $SIGPIPE_R, $SIGPIPE_W;
		1656	fcntl $SIGPIPE_R, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_R;
		1657	fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case
		1658
		1659	# not strictly required, as $^F is normally 2, but let's make sure...
		1660	fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
		1661	fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
1346	;	1662	}
1347	$asy->pipe_autodrain (0);
1348		1663
1349	$asy	1664	$SIGPIPE_R
		1665	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1666
		1667	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
		1668	}
		1669
		1670	*signal = $HAVE_ASYNC_INTERRUPT
		1671	? sub {
		1672	my (undef, %arg) = @_;
		1673
		1674	# async::interrupt
		1675	my $signal = sig2num $arg{signal};
		1676	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1677
		1678	$SIG_ASY{$signal} ||= new Async::Interrupt
		1679	cb => sub { undef $SIG_EV{$signal} },
		1680	signal => $signal,
		1681	pipe => [$SIGPIPE_R->filenos],
		1682	pipe_autodrain => 0,
		1683	;
		1684
		1685	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1686	}
		1687	: sub {
		1688	my (undef, %arg) = @_;
		1689
		1690	# pure perl
		1691	my $signal = sig2name $arg{signal};
		1692	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1693
		1694	$SIG{$signal} ||= sub {
		1695	local $!;
		1696	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
		1697	undef $SIG_EV{$signal};
		1698	};
		1699
		1700	# can't do signal processing without introducing races in pure perl,
		1701	# so limit the signal latency.
		1702	_sig_add;
		1703
		1704	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1705	}
		1706	;
		1707
		1708	*AnyEvent::Base::signal::DESTROY = sub {
		1709	my ($signal, $cb) = @{$_[0]};
		1710
		1711	_sig_del;
		1712
		1713	delete $SIG_CB{$signal}{$cb};
		1714
		1715	$HAVE_ASYNC_INTERRUPT
		1716	? delete $SIG_ASY{$signal}
		1717	: # delete doesn't work with older perls - they then
		1718	# print weird messages, or just unconditionally exit
		1719	# instead of getting the default action.
		1720	undef $SIG{$signal}
		1721	unless keys %{ $SIG_CB{$signal} };
1350	};	1722	};
1351		1723
1352	} else {	1724	*_signal_exec = sub {
1353	# pure perl	1725	$HAVE_ASYNC_INTERRUPT
		1726	? $SIGPIPE_R->drain
		1727	: sysread $SIGPIPE_R, (my $dummy), 9;
1354		1728
1355	$SIG{$signal} ||= sub {	1729	while (%SIG_EV) {
1356	local $!;	1730	for (keys %SIG_EV) {
1357	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;	1731	delete $SIG_EV{$_};
1358	undef $SIG_EV{$signal};	1732	&$_ for values %{ $SIG_CB{$_} || {} };
		1733	}
		1734	}
1359	};	1735	};
1360
1361	# can't do signal processing without introducing races in pure perl,
1362	# so limit the signal latency.
1363	_sig_add;
1364	}	1736	};
		1737	die if $@;
1365		1738
1366	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
1367	}
1368
1369	sub signal {
1370	# probe for availability of Async::Interrupt
1371	if (!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT} && eval "use Async::Interrupt 0.6 (); 1") {
1372	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1373
1374	$HAVE_ASYNC_INTERRUPT = 1;
1375	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1376	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R->fileno, poll => "r", cb => \&_signal_exec);
1377
1378	} else {
1379	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
1380
1381	require Fcntl;
1382
1383	if (AnyEvent::WIN32) {
1384	require AnyEvent::Util;
1385
1386	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1387	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1388	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1389	} else {
1390	pipe $SIGPIPE_R, $SIGPIPE_W;
1391	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
1392	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
1393
1394	# not strictly required, as $^F is normally 2, but let's make sure...
1395	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1396	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1397	}
1398
1399	$SIGPIPE_R
1400	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1401
1402	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1403	}
1404
1405	*signal = \&_signal;
1406	&signal	1739	&signal
1407	}
1408
1409	sub AnyEvent::Base::signal::DESTROY {
1410	my ($signal, $cb) = @{$_[0]};
1411
1412	_sig_del;
1413
1414	delete $SIG_CB{$signal}{$cb};
1415
1416	$HAVE_ASYNC_INTERRUPT
1417	? delete $SIG_ASY{$signal}
1418	: # delete doesn't work with older perls - they then
1419	# print weird messages, or just unconditionally exit
1420	# instead of getting the default action.
1421	undef $SIG{$signal}
1422	unless keys %{ $SIG_CB{$signal} };
1423	}	1740	}
1424		1741
1425	# default implementation for ->child	1742	# default implementation for ->child
1426		1743
1427	our %PID_CB;	1744	our %PID_CB;
1428	our $CHLD_W;	1745	our $CHLD_W;
1429	our $CHLD_DELAY_W;	1746	our $CHLD_DELAY_W;
1430	our $WNOHANG;
1431		1747
		1748	# used by many Impl's
1432	sub _emit_childstatus($$) {	1749	sub _emit_childstatus($$) {
1433	my (undef, $rpid, $rstatus) = @_;	1750	my (undef, $rpid, $rstatus) = @_;
1434		1751
1435	$_->($rpid, $rstatus)	1752	$_->($rpid, $rstatus)
1436	for values %{ $PID_CB{$rpid} || {} },	1753	for values %{ $PID_CB{$rpid} || {} },
1437	values %{ $PID_CB{0} || {} };	1754	values %{ $PID_CB{0} || {} };
1438	}	1755	}
1439		1756
1440	sub _sigchld {
1441	my $pid;
1442
1443	AnyEvent->_emit_childstatus ($pid, $?)
1444	while ($pid = waitpid -1, $WNOHANG) > 0;
1445	}
1446
1447	sub child {	1757	sub child {
		1758	eval q{ # poor man's autoloading {}
		1759	*_sigchld = sub {
		1760	my $pid;
		1761
		1762	AnyEvent->_emit_childstatus ($pid, $?)
		1763	while ($pid = waitpid -1, WNOHANG) > 0;
		1764	};
		1765
		1766	*child = sub {
1448	my (undef, %arg) = @_;	1767	my (undef, %arg) = @_;
1449		1768
1450	defined (my $pid = $arg{pid} + 0)	1769	my $pid = $arg{pid};
1451	or Carp::croak "required option 'pid' is missing";	1770	my $cb = $arg{cb};
1452		1771
1453	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1772	$PID_CB{$pid}{$cb+0} = $cb;
1454		1773
1455	# WNOHANG is almost cetrainly 1 everywhere
1456	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
1457	? 1
1458	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1459
1460	unless ($CHLD_W) {	1774	unless ($CHLD_W) {
1461	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1775	$CHLD_W = AE::signal CHLD => \&_sigchld;
1462	# child could be a zombie already, so make at least one round	1776	# child could be a zombie already, so make at least one round
1463	&_sigchld;	1777	&_sigchld;
1464	}	1778	}
1465		1779
1466	bless [$pid, $arg{cb}], "AnyEvent::Base::child"	1780	bless [$pid, $cb+0], "AnyEvent::Base::child"
1467	}	1781	};
1468		1782
1469	sub AnyEvent::Base::child::DESTROY {	1783	*AnyEvent::Base::child::DESTROY = sub {
1470	my ($pid, $cb) = @{$_[0]};	1784	my ($pid, $icb) = @{$_[0]};
1471		1785
1472	delete $PID_CB{$pid}{$cb};	1786	delete $PID_CB{$pid}{$icb};
1473	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1787	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1474		1788
1475	undef $CHLD_W unless keys %PID_CB;	1789	undef $CHLD_W unless keys %PID_CB;
		1790	};
		1791	};
		1792	die if $@;
		1793
		1794	&child
1476	}	1795	}
1477		1796
1478	# idle emulation is done by simply using a timer, regardless	1797	# idle emulation is done by simply using a timer, regardless
1479	# of whether the process is idle or not, and not letting	1798	# of whether the process is idle or not, and not letting
1480	# the callback use more than 50% of the time.	1799	# the callback use more than 50% of the time.
1481	sub idle {	1800	sub idle {
		1801	eval q{ # poor man's autoloading {}
		1802	*idle = sub {
1482	my (undef, %arg) = @_;	1803	my (undef, %arg) = @_;
1483		1804
1484	my ($cb, $w, $rcb) = $arg{cb};	1805	my ($cb, $w, $rcb) = $arg{cb};
1485		1806
1486	$rcb = sub {	1807	$rcb = sub {
1487	if ($cb) {	1808	if ($cb) {
1488	$w = _time;	1809	$w = AE::time;
1489	&$cb;	1810	&$cb;
1490	$w = _time - $w;	1811	$w = AE::time - $w;
1491		1812
1492	# never use more then 50% of the time for the idle watcher,	1813	# never use more then 50% of the time for the idle watcher,
1493	# within some limits	1814	# within some limits
1494	$w = 0.0001 if $w < 0.0001;	1815	$w = 0.0001 if $w < 0.0001;
1495	$w = 5 if $w > 5;	1816	$w = 5 if $w > 5;
1496		1817
1497	$w = AnyEvent->timer (after => $w, cb => $rcb);	1818	$w = AE::timer $w, 0, $rcb;
1498	} else {	1819	} else {
1499	# clean up...	1820	# clean up...
1500	undef $w;	1821	undef $w;
1501	undef $rcb;	1822	undef $rcb;
		1823	}
		1824	};
		1825
		1826	$w = AE::timer 0.05, 0, $rcb;
		1827
		1828	bless \\$cb, "AnyEvent::Base::idle"
1502	}	1829	};
		1830
		1831	*AnyEvent::Base::idle::DESTROY = sub {
		1832	undef $${$_[0]};
		1833	};
1503	};	1834	};
		1835	die if $@;
1504		1836
1505	$w = AnyEvent->timer (after => 0.05, cb => $rcb);	1837	&idle
1506
1507	bless \\$cb, "AnyEvent::Base::idle"
1508	}
1509
1510	sub AnyEvent::Base::idle::DESTROY {
1511	undef $${$_[0]};
1512	}	1838	}
1513		1839
1514	package AnyEvent::CondVar;	1840	package AnyEvent::CondVar;
1515		1841
1516	our @ISA = AnyEvent::CondVar::Base::;	1842	our @ISA = AnyEvent::CondVar::Base::;
		1843
		1844	# only to be used for subclassing
		1845	sub new {
		1846	my $class = shift;
		1847	bless AnyEvent->condvar (@_), $class
		1848	}
1517		1849
1518	package AnyEvent::CondVar::Base;	1850	package AnyEvent::CondVar::Base;
1519		1851
1520	#use overload	1852	#use overload
1521	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1853	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
…		…
1531		1863
1532	sub _send {	1864	sub _send {
1533	# nop	1865	# nop
1534	}	1866	}
1535		1867
		1868	sub _wait {
		1869	AnyEvent->_poll until $_[0]{_ae_sent};
		1870	}
		1871
1536	sub send {	1872	sub send {
1537	my $cv = shift;	1873	my $cv = shift;
1538	$cv->{_ae_sent} = [@_];	1874	$cv->{_ae_sent} = [@_];
1539	(delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};	1875	(delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};
1540	$cv->_send;	1876	$cv->_send;
…		…
1547		1883
1548	sub ready {	1884	sub ready {
1549	$_[0]{_ae_sent}	1885	$_[0]{_ae_sent}
1550	}	1886	}
1551		1887
1552	sub _wait {
1553	$WAITING
1554	and !$_[0]{_ae_sent}
1555	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
1556
1557	local $WAITING = 1;
1558	AnyEvent->one_event while !$_[0]{_ae_sent};
1559	}
1560
1561	sub recv {	1888	sub recv {
		1889	unless ($_[0]{_ae_sent}) {
		1890	$WAITING
		1891	and Carp::croak "AnyEvent::CondVar: recursive blocking wait attempted";
		1892
		1893	local $WAITING = 1;
1562	$_[0]->_wait;	1894	$_[0]->_wait;
		1895	}
1563		1896
1564	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1897	$_[0]{_ae_croak}
1565	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1898	and Carp::croak $_[0]{_ae_croak};
		1899
		1900	wantarray
		1901	? @{ $_[0]{_ae_sent} }
		1902	: $_[0]{_ae_sent}[0]
1566	}	1903	}
1567		1904
1568	sub cb {	1905	sub cb {
1569	$_[0]{_ae_cb} = $_[1] if @_ > 1;	1906	my $cv = shift;
		1907
		1908	@_
		1909	and $cv->{_ae_cb} = shift
		1910	and $cv->{_ae_sent}
		1911	and (delete $cv->{_ae_cb})->($cv);
		1912
1570	$_[0]{_ae_cb}	1913	$cv->{_ae_cb}
1571	}	1914	}
1572		1915
1573	sub begin {	1916	sub begin {
1574	++$_[0]{_ae_counter};	1917	++$_[0]{_ae_counter};
1575	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;	1918	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
…		…
1580	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };	1923	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };
1581	}	1924	}
1582		1925
1583	# undocumented/compatibility with pre-3.4	1926	# undocumented/compatibility with pre-3.4
1584	*broadcast = \&send;	1927	*broadcast = \&send;
1585	*wait = \&_wait;	1928	*wait = \&recv;
1586		1929
1587	=head1 ERROR AND EXCEPTION HANDLING	1930	=head1 ERROR AND EXCEPTION HANDLING
1588		1931
1589	In general, AnyEvent does not do any error handling - it relies on the	1932	In general, AnyEvent does not do any error handling - it relies on the
1590	caller to do that if required. The L<AnyEvent::Strict> module (see also	1933	caller to do that if required. The L<AnyEvent::Strict> module (see also
…		…
1637	check the arguments passed to most method calls. If it finds any problems,	1980	check the arguments passed to most method calls. If it finds any problems,
1638	it will croak.	1981	it will croak.
1639		1982
1640	In other words, enables "strict" mode.	1983	In other words, enables "strict" mode.
1641		1984
1642	Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>	1985	Unlike C<use strict> (or its modern cousin, C<< use L<common::sense>
1643	>>, it is definitely recommended to keep it off in production. Keeping	1986	>>, it is definitely recommended to keep it off in production. Keeping
1644	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs	1987	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
1645	can be very useful, however.	1988	can be very useful, however.
1646		1989
		1990	=item C<PERL_ANYEVENT_DEBUG_SHELL>
		1991
		1992	If this env variable is set, then its contents will be interpreted by
		1993	C<AnyEvent::Socket::parse_hostport> (after replacing every occurance of
		1994	C<$$> by the process pid) and an C<AnyEvent::Debug::shell> is bound on
		1995	that port. The shell object is saved in C<$AnyEvent::Debug::SHELL>.
		1996
		1997	This takes place when the first watcher is created.
		1998
		1999	For example, to bind a debug shell on a unix domain socket in
		2000	F<< /tmp/debug<pid>.sock >>, you could use this:
		2001
		2002	PERL_ANYEVENT_DEBUG_SHELL=/tmp/debug\$\$.sock perlprog
		2003
		2004	Note that creating sockets in F</tmp> is very unsafe on multiuser
		2005	systems.
		2006
		2007	=item C<PERL_ANYEVENT_DEBUG_WRAP>
		2008
		2009	Can be set to C<0>, C<1> or C<2> and enables wrapping of all watchers for
		2010	debugging purposes. See C<AnyEvent::Debug::wrap> for details.
		2011
1647	=item C<PERL_ANYEVENT_MODEL>	2012	=item C<PERL_ANYEVENT_MODEL>
1648		2013
1649	This can be used to specify the event model to be used by AnyEvent, before	2014	This can be used to specify the event model to be used by AnyEvent, before
1650	auto detection and -probing kicks in. It must be a string consisting	2015	auto detection and -probing kicks in.
1651	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended	2016
		2017	It normally is a string consisting entirely of ASCII letters (e.g. C<EV>
		2018	or C<IOAsync>). The string C<AnyEvent::Impl::> gets prepended and the
1652	and the resulting module name is loaded and if the load was successful,	2019	resulting module name is loaded and - if the load was successful - used as
1653	used as event model. If it fails to load AnyEvent will proceed with	2020	event model backend. If it fails to load then AnyEvent will proceed with
1654	auto detection and -probing.	2021	auto detection and -probing.
1655		2022
1656	This functionality might change in future versions.	2023	If the string ends with C<::> instead (e.g. C<AnyEvent::Impl::EV::>) then
		2024	nothing gets prepended and the module name is used as-is (hint: C<::> at
		2025	the end of a string designates a module name and quotes it appropriately).
1657		2026
1658	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you	2027	For example, to force the pure perl model (L<AnyEvent::Loop::Perl>) you
1659	could start your program like this:	2028	could start your program like this:
1660		2029
1661	PERL_ANYEVENT_MODEL=Perl perl ...	2030	PERL_ANYEVENT_MODEL=Perl perl ...
1662		2031
1663	=item C<PERL_ANYEVENT_PROTOCOLS>	2032	=item C<PERL_ANYEVENT_PROTOCOLS>
…		…
1784	warn "read: $input\n"; # output what has been read	2153	warn "read: $input\n"; # output what has been read
1785	$cv->send if $input =~ /^q/i; # quit program if /^q/i	2154	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1786	},	2155	},
1787	);	2156	);
1788		2157
1789	my $time_watcher; # can only be used once
1790
1791	sub new_timer {
1792	$timer = AnyEvent->timer (after => 1, cb => sub {	2158	my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1793	warn "timeout\n"; # print 'timeout' about every second	2159	warn "timeout\n"; # print 'timeout' at most every second
1794	&new_timer; # and restart the time
1795	});	2160	});
1796	}
1797
1798	new_timer; # create first timer
1799		2161
1800	$cv->recv; # wait until user enters /^q/i	2162	$cv->recv; # wait until user enters /^q/i
1801		2163
1802	=head1 REAL-WORLD EXAMPLE	2164	=head1 REAL-WORLD EXAMPLE
1803		2165
…		…
1876		2238
1877	The actual code goes further and collects all errors (C<die>s, exceptions)	2239	The actual code goes further and collects all errors (C<die>s, exceptions)
1878	that occurred during request processing. The C<result> method detects	2240	that occurred during request processing. The C<result> method detects
1879	whether an exception as thrown (it is stored inside the $txn object)	2241	whether an exception as thrown (it is stored inside the $txn object)
1880	and just throws the exception, which means connection errors and other	2242	and just throws the exception, which means connection errors and other
1881	problems get reported tot he code that tries to use the result, not in a	2243	problems get reported to the code that tries to use the result, not in a
1882	random callback.	2244	random callback.
1883		2245
1884	All of this enables the following usage styles:	2246	All of this enables the following usage styles:
1885		2247
1886	1. Blocking:	2248	1. Blocking:
…		…
1934	through AnyEvent. The benchmark creates a lot of timers (with a zero	2296	through AnyEvent. The benchmark creates a lot of timers (with a zero
1935	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	2297	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1936	which it is), lets them fire exactly once and destroys them again.	2298	which it is), lets them fire exactly once and destroys them again.
1937		2299
1938	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	2300	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1939	distribution.	2301	distribution. It uses the L<AE> interface, which makes a real difference
		2302	for the EV and Perl backends only.
1940		2303
1941	=head3 Explanation of the columns	2304	=head3 Explanation of the columns
1942		2305
1943	I<watcher> is the number of event watchers created/destroyed. Since	2306	I<watcher> is the number of event watchers created/destroyed. Since
1944	different event models feature vastly different performances, each event	2307	different event models feature vastly different performances, each event
…		…
1965	watcher.	2328	watcher.
1966		2329
1967	=head3 Results	2330	=head3 Results
1968		2331
1969	name watchers bytes create invoke destroy comment	2332	name watchers bytes create invoke destroy comment
1970	EV/EV 400000 224 0.47 0.35 0.27 EV native interface	2333	EV/EV 100000 223 0.47 0.43 0.27 EV native interface
1971	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	2334	EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
1972	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal	2335	Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
1973	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation	2336	Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
1974	Event/Event 16000 517 32.20 31.80 0.81 Event native interface	2337	Event/Event 16000 516 31.16 31.84 0.82 Event native interface
1975	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers	2338	Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
1976	IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll	2339	IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
1977	IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll	2340	IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
1978	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour	2341	Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
1979	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers	2342	Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
1980	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event	2343	POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
1981	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select	2344	POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
1982		2345
1983	=head3 Discussion	2346	=head3 Discussion
1984		2347
1985	The benchmark does I<not> measure scalability of the event loop very	2348	The benchmark does I<not> measure scalability of the event loop very
1986	well. For example, a select-based event loop (such as the pure perl one)	2349	well. For example, a select-based event loop (such as the pure perl one)
…		…
1998	benchmark machine, handling an event takes roughly 1600 CPU cycles with	2361	benchmark machine, handling an event takes roughly 1600 CPU cycles with
1999	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU	2362	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
2000	cycles with POE.	2363	cycles with POE.
2001		2364
2002	C<EV> is the sole leader regarding speed and memory use, which are both	2365	C<EV> is the sole leader regarding speed and memory use, which are both
2003	maximal/minimal, respectively. Even when going through AnyEvent, it uses	2366	maximal/minimal, respectively. When using the L<AE> API there is zero
		2367	overhead (when going through the AnyEvent API create is about 5-6 times
		2368	slower, with other times being equal, so still uses far less memory than
2004	far less memory than any other event loop and is still faster than Event	2369	any other event loop and is still faster than Event natively).
2005	natively.
2006		2370
2007	The pure perl implementation is hit in a few sweet spots (both the	2371	The pure perl implementation is hit in a few sweet spots (both the
2008	constant timeout and the use of a single fd hit optimisations in the perl	2372	constant timeout and the use of a single fd hit optimisations in the perl
2009	interpreter and the backend itself). Nevertheless this shows that it	2373	interpreter and the backend itself). Nevertheless this shows that it
2010	adds very little overhead in itself. Like any select-based backend its	2374	adds very little overhead in itself. Like any select-based backend its
…		…
2058	(even when used without AnyEvent), but most event loops have acceptable	2422	(even when used without AnyEvent), but most event loops have acceptable
2059	performance with or without AnyEvent.	2423	performance with or without AnyEvent.
2060		2424
2061	=item * The overhead AnyEvent adds is usually much smaller than the overhead of	2425	=item * The overhead AnyEvent adds is usually much smaller than the overhead of
2062	the actual event loop, only with extremely fast event loops such as EV	2426	the actual event loop, only with extremely fast event loops such as EV
2063	adds AnyEvent significant overhead.	2427	does AnyEvent add significant overhead.
2064		2428
2065	=item * You should avoid POE like the plague if you want performance or	2429	=item * You should avoid POE like the plague if you want performance or
2066	reasonable memory usage.	2430	reasonable memory usage.
2067		2431
2068	=back	2432	=back
…		…
2084	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100	2448	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
2085	(1%) are active. This mirrors the activity of large servers with many	2449	(1%) are active. This mirrors the activity of large servers with many
2086	connections, most of which are idle at any one point in time.	2450	connections, most of which are idle at any one point in time.
2087		2451
2088	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	2452	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
2089	distribution.	2453	distribution. It uses the L<AE> interface, which makes a real difference
		2454	for the EV and Perl backends only.
2090		2455
2091	=head3 Explanation of the columns	2456	=head3 Explanation of the columns
2092		2457
2093	I<sockets> is the number of sockets, and twice the number of "servers" (as	2458	I<sockets> is the number of sockets, and twice the number of "servers" (as
2094	each server has a read and write socket end).	2459	each server has a read and write socket end).
…		…
2102	a new one that moves the timeout into the future.	2467	a new one that moves the timeout into the future.
2103		2468
2104	=head3 Results	2469	=head3 Results
2105		2470
2106	name sockets create request	2471	name sockets create request
2107	EV 20000 69.01 11.16	2472	EV 20000 62.66 7.99
2108	Perl 20000 73.32 35.87	2473	Perl 20000 68.32 32.64
2109	IOAsync 20000 157.00 98.14 epoll	2474	IOAsync 20000 174.06 101.15 epoll
2110	IOAsync 20000 159.31 616.06 poll	2475	IOAsync 20000 174.67 610.84 poll
2111	Event 20000 212.62 257.32	2476	Event 20000 202.69 242.91
2112	Glib 20000 651.16 1896.30	2477	Glib 20000 557.01 1689.52
2113	POE 20000 349.67 12317.24 uses POE::Loop::Event	2478	POE 20000 341.54 12086.32 uses POE::Loop::Event
2114		2479
2115	=head3 Discussion	2480	=head3 Discussion
2116		2481
2117	This benchmark I<does> measure scalability and overall performance of the	2482	This benchmark I<does> measure scalability and overall performance of the
2118	particular event loop.	2483	particular event loop.
…		…
2244	As you can see, the AnyEvent + EV combination even beats the	2609	As you can see, the AnyEvent + EV combination even beats the
2245	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl	2610	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
2246	backend easily beats IO::Lambda and POE.	2611	backend easily beats IO::Lambda and POE.
2247		2612
2248	And even the 100% non-blocking version written using the high-level (and	2613	And even the 100% non-blocking version written using the high-level (and
2249	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a	2614	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
2250	large margin, even though it does all of DNS, tcp-connect and socket I/O	2615	higher level ("unoptimised") abstractions by a large margin, even though
2251	in a non-blocking way.	2616	it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
2252		2617
2253	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and	2618	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
2254	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are	2619	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
2255	part of the IO::lambda distribution and were used without any changes.	2620	part of the IO::Lambda distribution and were used without any changes.
2256		2621
2257		2622
2258	=head1 SIGNALS	2623	=head1 SIGNALS
2259		2624
2260	AnyEvent currently installs handlers for these signals:	2625	AnyEvent currently installs handlers for these signals:
…		…
2297	unless defined $SIG{PIPE};	2662	unless defined $SIG{PIPE};
2298		2663
2299	=head1 RECOMMENDED/OPTIONAL MODULES	2664	=head1 RECOMMENDED/OPTIONAL MODULES
2300		2665
2301	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and	2666	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
2302	it's built-in modules) are required to use it.	2667	its built-in modules) are required to use it.
2303		2668
2304	That does not mean that AnyEvent won't take advantage of some additional	2669	That does not mean that AnyEvent won't take advantage of some additional
2305	modules if they are installed.	2670	modules if they are installed.
2306		2671
2307	This section epxlains which additional modules will be used, and how they	2672	This section explains which additional modules will be used, and how they
2308	affect AnyEvent's operetion.	2673	affect AnyEvent's operation.
2309		2674
2310	=over 4	2675	=over 4
2311		2676
2312	=item L<Async::Interrupt>	2677	=item L<Async::Interrupt>
2313		2678
…		…
2318	catch the signals) with some delay (default is 10 seconds, look for	2683	catch the signals) with some delay (default is 10 seconds, look for
2319	C<$AnyEvent::MAX_SIGNAL_LATENCY>).	2684	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
2320		2685
2321	If this module is available, then it will be used to implement signal	2686	If this module is available, then it will be used to implement signal
2322	catching, which means that signals will not be delayed, and the event loop	2687	catching, which means that signals will not be delayed, and the event loop
2323	will not be interrupted regularly, which is more efficient (And good for	2688	will not be interrupted regularly, which is more efficient (and good for
2324	battery life on laptops).	2689	battery life on laptops).
2325		2690
2326	This affects not just the pure-perl event loop, but also other event loops	2691	This affects not just the pure-perl event loop, but also other event loops
2327	that have no signal handling on their own (e.g. Glib, Tk, Qt).	2692	that have no signal handling on their own (e.g. Glib, Tk, Qt).
2328		2693
…		…
2340	automatic timer adjustments even when no monotonic clock is available,	2705	automatic timer adjustments even when no monotonic clock is available,
2341	can take avdantage of advanced kernel interfaces such as C<epoll> and	2706	can take avdantage of advanced kernel interfaces such as C<epoll> and
2342	C<kqueue>, and is the fastest backend I<by far>. You can even embed	2707	C<kqueue>, and is the fastest backend I<by far>. You can even embed
2343	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).	2708	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
2344		2709
		2710	If you only use backends that rely on another event loop (e.g. C<Tk>),
		2711	then this module will do nothing for you.
		2712
2345	=item L<Guard>	2713	=item L<Guard>
2346		2714
2347	The guard module, when used, will be used to implement	2715	The guard module, when used, will be used to implement
2348	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a	2716	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
2349	lot less memory), but otherwise doesn't affect guard operation much. It is	2717	lot less memory), but otherwise doesn't affect guard operation much. It is
2350	purely used for performance.	2718	purely used for performance.
2351		2719
2352	=item L<JSON> and L<JSON::XS>	2720	=item L<JSON> and L<JSON::XS>
2353		2721
2354	This module is required when you want to read or write JSON data via	2722	One of these modules is required when you want to read or write JSON data
2355	L<AnyEvent::Handle>. It is also written in pure-perl, but can take	2723	via L<AnyEvent::Handle>. L<JSON> is also written in pure-perl, but can take
2356	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.	2724	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
2357
2358	In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
2359	installed.
2360		2725
2361	=item L<Net::SSLeay>	2726	=item L<Net::SSLeay>
2362		2727
2363	Implementing TLS/SSL in Perl is certainly interesting, but not very	2728	Implementing TLS/SSL in Perl is certainly interesting, but not very
2364	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with	2729	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
2365	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.	2730	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
2366		2731
2367	=item L<Time::HiRes>	2732	=item L<Time::HiRes>
2368		2733
2369	This module is part of perl since release 5.008. It will be used when the	2734	This module is part of perl since release 5.008. It will be used when the
2370	chosen event library does not come with a timing source on it's own. The	2735	chosen event library does not come with a timing source of its own. The
2371	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to	2736	pure-perl event loop (L<AnyEvent::Loop>) will additionally load it to
2372	try to use a monotonic clock for timing stability.	2737	try to use a monotonic clock for timing stability.
2373		2738
2374	=back	2739	=back
2375		2740
2376		2741
2377	=head1 FORK	2742	=head1 FORK
2378		2743
2379	Most event libraries are not fork-safe. The ones who are usually are	2744	Most event libraries are not fork-safe. The ones who are usually are
2380	because they rely on inefficient but fork-safe C<select> or C<poll>	2745	because they rely on inefficient but fork-safe C<select> or C<poll> calls
2381	calls. Only L<EV> is fully fork-aware.	2746	- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
		2747	are usually badly thought-out hacks that are incompatible with fork in
		2748	one way or another. Only L<EV> is fully fork-aware and ensures that you
		2749	continue event-processing in both parent and child (or both, if you know
		2750	what you are doing).
		2751
		2752	This means that, in general, you cannot fork and do event processing in
		2753	the child if the event library was initialised before the fork (which
		2754	usually happens when the first AnyEvent watcher is created, or the library
		2755	is loaded).
2382		2756
2383	If you have to fork, you must either do so I<before> creating your first	2757	If you have to fork, you must either do so I<before> creating your first
2384	watcher OR you must not use AnyEvent at all in the child OR you must do	2758	watcher OR you must not use AnyEvent at all in the child OR you must do
2385	something completely out of the scope of AnyEvent.	2759	something completely out of the scope of AnyEvent.
		2760
		2761	The problem of doing event processing in the parent I<and> the child
		2762	is much more complicated: even for backends that I<are> fork-aware or
		2763	fork-safe, their behaviour is not usually what you want: fork clones all
		2764	watchers, that means all timers, I/O watchers etc. are active in both
		2765	parent and child, which is almost never what you want. USing C<exec>
		2766	to start worker children from some kind of manage rprocess is usually
		2767	preferred, because it is much easier and cleaner, at the expense of having
		2768	to have another binary.
2386		2769
2387		2770
2388	=head1 SECURITY CONSIDERATIONS	2771	=head1 SECURITY CONSIDERATIONS
2389		2772
2390	AnyEvent can be forced to load any event model via	2773	AnyEvent can be forced to load any event model via
…		…
2420	pronounced).	2803	pronounced).
2421		2804
2422		2805
2423	=head1 SEE ALSO	2806	=head1 SEE ALSO
2424		2807
		2808	Tutorial/Introduction: L<AnyEvent::Intro>.
		2809
		2810	FAQ: L<AnyEvent::FAQ>.
		2811
2425	Utility functions: L<AnyEvent::Util>.	2812	Utility functions: L<AnyEvent::Util>.
2426		2813
2427	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,	2814	Event modules: L<AnyEvent::Loop>, L<EV>, L<EV::Glib>, L<Glib::EV>,
2428	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2815	L<Event>, L<Glib::Event>, L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
2429		2816
2430	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2817	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
2431	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2818	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
2432	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2819	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
2433	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.	2820	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.
…		…
2435	Non-blocking file handles, sockets, TCP clients and	2822	Non-blocking file handles, sockets, TCP clients and
2436	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.	2823	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2437		2824
2438	Asynchronous DNS: L<AnyEvent::DNS>.	2825	Asynchronous DNS: L<AnyEvent::DNS>.
2439		2826
2440	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,	2827	Thread support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>.
2441	L<Coro::Event>,
2442		2828
2443	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,	2829	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::IRC>,
2444	L<AnyEvent::HTTP>.	2830	L<AnyEvent::HTTP>.
2445		2831
2446		2832
2447	=head1 AUTHOR	2833	=head1 AUTHOR
2448		2834

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