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Revision 1.356 by root, Fri Aug 12 18:41:25 2011 UTC

1	=head1 NAME	1	=head1 NAME
2		2
3	AnyEvent - provide framework for multiple event loops	3	AnyEvent - the DBI of event loop programming
4		4
5	EV, Event, Glib, Tk, Perl, Event::Lib, Qt and POE are various supported	5	EV, Event, Glib, Tk, Perl, Event::Lib, Irssi, rxvt-unicode, IO::Async, Qt
6	event loops.	6	and POE are various supported event loops/environments.
7		7
8	=head1 SYNOPSIS	8	=head1 SYNOPSIS
9		9
10	use AnyEvent;	10	use AnyEvent;
11		11
		12	# if you prefer function calls, look at the AE manpage for
		13	# an alternative API.
		14
12	# file descriptor readable	15	# file handle or descriptor readable
13	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });	16	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });
14		17
15	# one-shot or repeating timers	18	# one-shot or repeating timers
16	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });	19	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
17	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...	20	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...);
18		21
19	print AnyEvent->now; # prints current event loop time	22	print AnyEvent->now; # prints current event loop time
20	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.	23	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
21		24
22	# POSIX signal	25	# POSIX signal
…		…
40	=head1 INTRODUCTION/TUTORIAL	43	=head1 INTRODUCTION/TUTORIAL
41		44
42	This manpage is mainly a reference manual. If you are interested	45	This manpage is mainly a reference manual. If you are interested
43	in a tutorial or some gentle introduction, have a look at the	46	in a tutorial or some gentle introduction, have a look at the
44	L<AnyEvent::Intro> manpage.	47	L<AnyEvent::Intro> manpage.
		48
		49	=head1 SUPPORT
		50
		51	An FAQ document is available as L<AnyEvent::FAQ>.
		52
		53	There also is a mailinglist for discussing all things AnyEvent, and an IRC
		54	channel, too.
		55
		56	See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software
		57	Repository>, at L<http://anyevent.schmorp.de>, for more info.
45		58
46	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)	59	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
47		60
48	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen	61	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
49	nowadays. So what is different about AnyEvent?	62	nowadays. So what is different about AnyEvent?
…		…
65	module users into the same thing by forcing them to use the same event	78	module users into the same thing by forcing them to use the same event
66	model you use.	79	model you use.
67		80
68	For modules like POE or IO::Async (which is a total misnomer as it is	81	For modules like POE or IO::Async (which is a total misnomer as it is
69	actually doing all I/O I<synchronously>...), using them in your module is	82	actually doing all I/O I<synchronously>...), using them in your module is
70	like joining a cult: After you joined, you are dependent on them and you	83	like joining a cult: After you join, you are dependent on them and you
71	cannot use anything else, as they are simply incompatible to everything	84	cannot use anything else, as they are simply incompatible to everything
72	that isn't them. What's worse, all the potential users of your	85	that isn't them. What's worse, all the potential users of your
73	module are I<also> forced to use the same event loop you use.	86	module are I<also> forced to use the same event loop you use.
74		87
75	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works	88	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
76	fine. AnyEvent + Tk works fine etc. etc. but none of these work together	89	fine. AnyEvent + Tk works fine etc. etc. but none of these work together
77	with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if	90	with the rest: POE + EV? No go. Tk + Event? No go. Again: if your module
78	your module uses one of those, every user of your module has to use it,	91	uses one of those, every user of your module has to use it, too. But if
79	too. But if your module uses AnyEvent, it works transparently with all	92	your module uses AnyEvent, it works transparently with all event models it
80	event models it supports (including stuff like IO::Async, as long as those	93	supports (including stuff like IO::Async, as long as those use one of the
81	use one of the supported event loops. It is trivial to add new event loops	94	supported event loops. It is easy to add new event loops to AnyEvent, too,
82	to AnyEvent, too, so it is future-proof).	95	so it is future-proof).
83		96
84	In addition to being free of having to use I<the one and only true event	97	In addition to being free of having to use I<the one and only true event
85	model>, AnyEvent also is free of bloat and policy: with POE or similar	98	model>, AnyEvent also is free of bloat and policy: with POE or similar
86	modules, you get an enormous amount of code and strict rules you have to	99	modules, you get an enormous amount of code and strict rules you have to
87	follow. AnyEvent, on the other hand, is lean and up to the point, by only	100	follow. AnyEvent, on the other hand, is lean and to the point, by only
88	offering the functionality that is necessary, in as thin as a wrapper as	101	offering the functionality that is necessary, in as thin as a wrapper as
89	technically possible.	102	technically possible.
90		103
91	Of course, AnyEvent comes with a big (and fully optional!) toolbox	104	Of course, AnyEvent comes with a big (and fully optional!) toolbox
92	of useful functionality, such as an asynchronous DNS resolver, 100%	105	of useful functionality, such as an asynchronous DNS resolver, 100%
…		…
98	useful) and you want to force your users to use the one and only event	111	useful) and you want to force your users to use the one and only event
99	model, you should I<not> use this module.	112	model, you should I<not> use this module.
100		113
101	=head1 DESCRIPTION	114	=head1 DESCRIPTION
102		115
103	L<AnyEvent> provides an identical interface to multiple event loops. This	116	L<AnyEvent> provides a uniform interface to various event loops. This
104	allows module authors to utilise an event loop without forcing module	117	allows module authors to use event loop functionality without forcing
105	users to use the same event loop (as only a single event loop can coexist	118	module users to use a specific event loop implementation (since more
106	peacefully at any one time).	119	than one event loop cannot coexist peacefully).
107		120
108	The interface itself is vaguely similar, but not identical to the L<Event>	121	The interface itself is vaguely similar, but not identical to the L<Event>
109	module.	122	module.
110		123
111	During the first call of any watcher-creation method, the module tries	124	During the first call of any watcher-creation method, the module tries
112	to detect the currently loaded event loop by probing whether one of the	125	to detect the currently loaded event loop by probing whether one of the
113	following modules is already loaded: L<EV>,	126	following modules is already loaded: L<EV>, L<AnyEvent::Loop>,
114	L<Event>, L<Glib>, L<AnyEvent::Impl::Perl>, L<Tk>, L<Event::Lib>, L<Qt>,	127	L<Event>, L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. The first one
115	L<POE>. The first one found is used. If none are found, the module tries	128	found is used. If none are detected, the module tries to load the first
116	to load these modules (excluding Tk, Event::Lib, Qt and POE as the pure perl	129	four modules in the order given; but note that if L<EV> is not
117	adaptor should always succeed) in the order given. The first one that can	130	available, the pure-perl L<AnyEvent::Loop> should always work, so
118	be successfully loaded will be used. If, after this, still none could be	131	the other two are not normally tried.
119	found, AnyEvent will fall back to a pure-perl event loop, which is not
120	very efficient, but should work everywhere.
121		132
122	Because AnyEvent first checks for modules that are already loaded, loading	133	Because AnyEvent first checks for modules that are already loaded, loading
123	an event model explicitly before first using AnyEvent will likely make	134	an event model explicitly before first using AnyEvent will likely make
124	that model the default. For example:	135	that model the default. For example:
125		136
…		…
127	use AnyEvent;	138	use AnyEvent;
128		139
129	# .. AnyEvent will likely default to Tk	140	# .. AnyEvent will likely default to Tk
130		141
131	The I<likely> means that, if any module loads another event model and	142	The I<likely> means that, if any module loads another event model and
132	starts using it, all bets are off. Maybe you should tell their authors to	143	starts using it, all bets are off - this case should be very rare though,
133	use AnyEvent so their modules work together with others seamlessly...	144	as very few modules hardcode event loops without announcing this very
		145	loudly.
134		146
135	The pure-perl implementation of AnyEvent is called	147	The pure-perl implementation of AnyEvent is called C<AnyEvent::Loop>. Like
136	C<AnyEvent::Impl::Perl>. Like other event modules you can load it	148	other event modules you can load it explicitly and enjoy the high
137	explicitly and enjoy the high availability of that event loop :)	149	availability of that event loop :)
138		150
139	=head1 WATCHERS	151	=head1 WATCHERS
140		152
141	AnyEvent has the central concept of a I<watcher>, which is an object that	153	AnyEvent has the central concept of a I<watcher>, which is an object that
142	stores relevant data for each kind of event you are waiting for, such as	154	stores relevant data for each kind of event you are waiting for, such as
…		…
147	callback when the event occurs (of course, only when the event model	159	callback when the event occurs (of course, only when the event model
148	is in control).	160	is in control).
149		161
150	Note that B<callbacks must not permanently change global variables>	162	Note that B<callbacks must not permanently change global variables>
151	potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<	163	potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<
152	callbacks must not C<die> >>. The former is good programming practise in	164	callbacks must not C<die> >>. The former is good programming practice in
153	Perl and the latter stems from the fact that exception handling differs	165	Perl and the latter stems from the fact that exception handling differs
154	widely between event loops.	166	widely between event loops.
155		167
156	To disable the watcher you have to destroy it (e.g. by setting the	168	To disable a watcher you have to destroy it (e.g. by setting the
157	variable you store it in to C<undef> or otherwise deleting all references	169	variable you store it in to C<undef> or otherwise deleting all references
158	to it).	170	to it).
159		171
160	All watchers are created by calling a method on the C<AnyEvent> class.	172	All watchers are created by calling a method on the C<AnyEvent> class.
161		173
162	Many watchers either are used with "recursion" (repeating timers for	174	Many watchers either are used with "recursion" (repeating timers for
163	example), or need to refer to their watcher object in other ways.	175	example), or need to refer to their watcher object in other ways.
164		176
165	An any way to achieve that is this pattern:	177	One way to achieve that is this pattern:
166		178
167	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {	179	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
168	# you can use $w here, for example to undef it	180	# you can use $w here, for example to undef it
169	undef $w;	181	undef $w;
170	});	182	});
…		…
173	my variables are only visible after the statement in which they are	185	my variables are only visible after the statement in which they are
174	declared.	186	declared.
175		187
176	=head2 I/O WATCHERS	188	=head2 I/O WATCHERS
177		189
		190	$w = AnyEvent->io (
		191	fh => <filehandle_or_fileno>,
		192	poll => <"r" or "w">,
		193	cb => <callback>,
		194	);
		195
178	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	196	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
179	with the following mandatory key-value pairs as arguments:	197	with the following mandatory key-value pairs as arguments:
180		198
181	C<fh> is the Perl I<file handle> (I<not> file descriptor, see below) to	199	C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch
182	watch for events (AnyEvent might or might not keep a reference to this	200	for events (AnyEvent might or might not keep a reference to this file
183	file handle). Note that only file handles pointing to things for which	201	handle). Note that only file handles pointing to things for which
184	non-blocking operation makes sense are allowed. This includes sockets,	202	non-blocking operation makes sense are allowed. This includes sockets,
185	most character devices, pipes, fifos and so on, but not for example files	203	most character devices, pipes, fifos and so on, but not for example files
186	or block devices.	204	or block devices.
187		205
188	C<poll> must be a string that is either C<r> or C<w>, which creates a	206	C<poll> must be a string that is either C<r> or C<w>, which creates a
…		…
196		214
197	The I/O watcher might use the underlying file descriptor or a copy of it.	215	The I/O watcher might use the underlying file descriptor or a copy of it.
198	You must not close a file handle as long as any watcher is active on the	216	You must not close a file handle as long as any watcher is active on the
199	underlying file descriptor.	217	underlying file descriptor.
200		218
201	Some event loops issue spurious readyness notifications, so you should	219	Some event loops issue spurious readiness notifications, so you should
202	always use non-blocking calls when reading/writing from/to your file	220	always use non-blocking calls when reading/writing from/to your file
203	handles.	221	handles.
204		222
205	Example: wait for readability of STDIN, then read a line and disable the	223	Example: wait for readability of STDIN, then read a line and disable the
206	watcher.	224	watcher.
…		…
209	chomp (my $input = <STDIN>);	227	chomp (my $input = <STDIN>);
210	warn "read: $input\n";	228	warn "read: $input\n";
211	undef $w;	229	undef $w;
212	});	230	});
213		231
214	=head3 GETTING A FILE HANDLE FROM A FILE DESCRIPTOR
215
216	It is not uncommon to only have a file descriptor, while AnyEvent requires
217	a Perl file handle.
218
219	There are basically two methods to convert a file descriptor into a file handle. If you own
220	the file descriptor, you can open it with C<&=>, as in:
221
222	open my $fh, "<&=$fileno" or die "xxx: §!";
223
224	This will "own" the file descriptor, meaning that when C<$fh> is
225	destroyed, it will automatically close the C<$fileno>. Also, note that
226	the open mode (read, write, read/write) must correspond with how the
227	underlying file descriptor was opened.
228
229	In many cases, taking over the file descriptor is now what you want, in
230	which case the only alternative is to dup the file descriptor:
231
232	open my $fh, "<&$fileno" or die "xxx: $!";
233
234	This has the advantage of not closing the file descriptor and the
235	disadvantage of making a slow copy.
236
237	=head2 TIME WATCHERS	232	=head2 TIME WATCHERS
		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	);
238		241
239	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 >>
240	method with the following mandatory arguments:	243	method with the following mandatory arguments:
241		244
242	C<after> specifies after how many seconds (fractional values are	245	C<after> specifies after how many seconds (fractional values are
…		…
245		248
246	Although the callback might get passed parameters, their value and	249	Although the callback might get passed parameters, their value and
247	presence is undefined and you cannot rely on them. Portable AnyEvent	250	presence is undefined and you cannot rely on them. Portable AnyEvent
248	callbacks cannot use arguments passed to time watcher callbacks.	251	callbacks cannot use arguments passed to time watcher callbacks.
249		252
250	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
251	parameter, C<interval>, as a strictly positive number (> 0), then the	254	parameter, C<interval>, as a strictly positive number (> 0), then the
252	callback will be invoked regularly at that interval (in fractional	255	callback will be invoked regularly at that interval (in fractional
253	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
254	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.
255		258
256	The callback will be rescheduled before invoking the callback, but no	259	The callback will be rescheduled before invoking the callback, but no
257	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
258	only approximate.	261	only approximate.
259		262
260	Example: fire an event after 7.7 seconds.	263	Example: fire an event after 7.7 seconds.
261		264
262	my $w = AnyEvent->timer (after => 7.7, cb => sub {	265	my $w = AnyEvent->timer (after => 7.7, cb => sub {
…		…
280		283
281	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
282	use absolute time internally. This makes a difference when your clock	285	use absolute time internally. This makes a difference when your clock
283	"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
284	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
285	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.
286		289
287	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
288	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
289	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)
290	timers.	293	timers.
291		294
292	AnyEvent always prefers relative timers, if available, matching the	295	AnyEvent always prefers relative timers, if available, matching the
293	AnyEvent API.	296	AnyEvent API.
…		…
315	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
316	function to call when you want to know the current time.>	319	function to call when you want to know the current time.>
317		320
318	This function is also often faster then C<< AnyEvent->time >>, and	321	This function is also often faster then C<< AnyEvent->time >>, and
319	thus the preferred method if you want some timestamp (for example,	322	thus the preferred method if you want some timestamp (for example,
320	L<AnyEvent::Handle> uses this to update it's activity timeouts).	323	L<AnyEvent::Handle> uses this to update its activity timeouts).
321		324
322	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
323	with your timing, you can skip it without bad conscience.	326	with your timing; you can skip it without a bad conscience.
324		327
325	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>
326	and L<EV> and the following set-up:	329	and L<EV> and the following set-up:
327		330
328	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
329	time=500 (assume no other callbacks delay processing). In your callback,	332	time=500 (assume no other callbacks delay processing). In your callback,
330	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
331	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
332	after three seconds.	335	after three seconds.
333		336
…		…
353	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into	356	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
354	account.	357	account.
355		358
356	=item AnyEvent->now_update	359	=item AnyEvent->now_update
357		360
358	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
359	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 >>,
360	AnyEvent->now >>, above).	363	above).
361		364
362	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
363	this "current" time will differ substantially from the real time, which	366	this "current" time will differ substantially from the real time, which
364	might affect timers and time-outs.	367	might affect timers and time-outs.
365		368
366	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
367	event loop's idea of "current time".	370	event loop's idea of "current time".
368		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
369	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.
370		380
371	=back	381	=back
372		382
373	=head2 SIGNAL WATCHERS	383	=head2 SIGNAL WATCHERS
		384
		385	$w = AnyEvent->signal (signal => <uppercase_signal_name>, cb => <callback>);
374		386
375	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
376	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
377	callback to be invoked whenever a signal occurs.	389	callback to be invoked whenever a signal occurs.
378		390
…		…
384	invocation, and callback invocation will be synchronous. Synchronous means	396	invocation, and callback invocation will be synchronous. Synchronous means
385	that it might take a while until the signal gets handled by the process,	397	that it might take a while until the signal gets handled by the process,
386	but it is guaranteed not to interrupt any other callbacks.	398	but it is guaranteed not to interrupt any other callbacks.
387		399
388	The main advantage of using these watchers is that you can share a signal	400	The main advantage of using these watchers is that you can share a signal
389	between multiple watchers.	401	between multiple watchers, and AnyEvent will ensure that signals will not
		402	interrupt your program at bad times.
390		403
391	This watcher might use C<%SIG>, so programs overwriting those signals	404	This watcher might use C<%SIG> (depending on the event loop used),
392	directly will likely not work correctly.	405	so programs overwriting those signals directly will likely not work
		406	correctly.
393		407
394	Example: exit on SIGINT	408	Example: exit on SIGINT
395		409
396	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });	410	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
397		411
		412	=head3 Restart Behaviour
		413
		414	While restart behaviour is up to the event loop implementation, most will
		415	not restart syscalls (that includes L<Async::Interrupt> and AnyEvent's
		416	pure perl implementation).
		417
		418	=head3 Safe/Unsafe Signals
		419
		420	Perl signals can be either "safe" (synchronous to opcode handling) or
		421	"unsafe" (asynchronous) - the former might get delayed indefinitely, the
		422	latter might corrupt your memory.
		423
		424	AnyEvent signal handlers are, in addition, synchronous to the event loop,
		425	i.e. they will not interrupt your running perl program but will only be
		426	called as part of the normal event handling (just like timer, I/O etc.
		427	callbacks, too).
		428
		429	=head3 Signal Races, Delays and Workarounds
		430
		431	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
		432	callbacks to signals in a generic way, which is a pity, as you cannot
		433	do race-free signal handling in perl, requiring C libraries for
		434	this. AnyEvent will try to do its best, which means in some cases,
		435	signals will be delayed. The maximum time a signal might be delayed is
		436	specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This
		437	variable can be changed only before the first signal watcher is created,
		438	and should be left alone otherwise. This variable determines how often
		439	AnyEvent polls for signals (in case a wake-up was missed). Higher values
		440	will cause fewer spurious wake-ups, which is better for power and CPU
		441	saving.
		442
		443	All these problems can be avoided by installing the optional
		444	L<Async::Interrupt> module, which works with most event loops. It will not
		445	work with inherently broken event loops such as L<Event> or L<Event::Lib>
		446	(and not with L<POE> currently, as POE does its own workaround with
		447	one-second latency). For those, you just have to suffer the delays.
		448
398	=head2 CHILD PROCESS WATCHERS	449	=head2 CHILD PROCESS WATCHERS
399		450
		451	$w = AnyEvent->child (pid => <process id>, cb => <callback>);
		452
400	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.
401		454
402	The child process is specified by the C<pid> argument (if set to C<0>, it	455	The child process is specified by the C<pid> argument (on some backends,
403	watches for any child process exit). The watcher will triggered only when	456	using C<0> watches for any child process exit, on others this will
404	the child process has finished and an exit status is available, not on	457	croak). The watcher will be triggered only when the child process has
405	any trace events (stopped/continued).	458	finished and an exit status is available, not on any trace events
		459	(stopped/continued).
406		460
407	The callback will be called with the pid and exit status (as returned by	461	The callback will be called with the pid and exit status (as returned by
408	waitpid), so unlike other watcher types, you I<can> rely on child watcher	462	waitpid), so unlike other watcher types, you I<can> rely on child watcher
409	callback arguments.	463	callback arguments.
410		464
…		…
426		480
427	This means you cannot create a child watcher as the very first	481	This means you cannot create a child watcher as the very first
428	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
429	watcher before you C<fork> the child (alternatively, you can call	483	watcher before you C<fork> the child (alternatively, you can call
430	C<AnyEvent::detect>).	484	C<AnyEvent::detect>).
		485
		486	As most event loops do not support waiting for child events, they will be
		487	emulated by AnyEvent in most cases, in which case the latency and race
		488	problems mentioned in the description of signal watchers apply.
431		489
432	Example: fork a process and wait for it	490	Example: fork a process and wait for it
433		491
434	my $done = AnyEvent->condvar;	492	my $done = AnyEvent->condvar;
435		493
…		…
447	# do something else, then wait for process exit	505	# do something else, then wait for process exit
448	$done->recv;	506	$done->recv;
449		507
450	=head2 IDLE WATCHERS	508	=head2 IDLE WATCHERS
451		509
452	Sometimes there is a need to do something, but it is not so important	510	$w = AnyEvent->idle (cb => <callback>);
453	to do it instantly, but only when there is nothing better to do. This
454	"nothing better to do" is usually defined to be "no other events need
455	attention by the event loop".
456		511
457	Idle watchers ideally get invoked when the event loop has nothing	512	This will repeatedly invoke the callback after the process becomes idle,
458	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.
459	events. Instead of blocking, the idle watcher is invoked.
460		514
461	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
462	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
463	will simply call the callback "from time to time".	526	will simply call the callback "from time to time".
464		527
465	Example: read lines from STDIN, but only process them when the	528	Example: read lines from STDIN, but only process them when the
466	program is otherwise idle:	529	program is otherwise idle:
…		…
482	});	545	});
483	});	546	});
484		547
485	=head2 CONDITION VARIABLES	548	=head2 CONDITION VARIABLES
486		549
		550	$cv = AnyEvent->condvar;
		551
		552	$cv->send (<list>);
		553	my @res = $cv->recv;
		554
487	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
488	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
489	will actively watch for new events and call your callbacks.	557	will actively watch for new events and call your callbacks.
490		558
491	AnyEvent is different, it expects somebody else to run the event loop and	559	AnyEvent is slightly different: it expects somebody else to run the event
492	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).
493		561
494	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
495	because they represent a condition that must become true.	563	they represent a condition that must become true.
		564
		565	Now is probably a good time to look at the examples further below.
496		566
497	Condition variables can be created by calling the C<< AnyEvent->condvar	567	Condition variables can be created by calling the C<< AnyEvent->condvar
498	>> method, usually without arguments. The only argument pair allowed is	568	>> method, usually without arguments. The only argument pair allowed is
499
500	C<cb>, which specifies a callback to be called when the condition variable	569	C<cb>, which specifies a callback to be called when the condition variable
501	becomes true, with the condition variable as the first argument (but not	570	becomes true, with the condition variable as the first argument (but not
502	the results).	571	the results).
503		572
504	After creation, the condition variable is "false" until it becomes "true"	573	After creation, the condition variable is "false" until it becomes "true"
505	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
506	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<<
507	->send >> method).	576	->send >> method).
508		577
509	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
510	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:
511	in time where multiple outstanding events have been processed. And yet	580
512	another way to call them is transactions - each condition variable can be	581	=over 4
513	used to represent a transaction, which finishes at some point and delivers	582
514	a result.	583	=item * Condition variables are like callbacks - you can call them (and pass them instead
		584	of callbacks). Unlike callbacks however, you can also wait for them to be called.
		585
		586	=item * Condition variables are signals - one side can emit or send them,
		587	the other side can wait for them, or install a handler that is called when
		588	the signal fires.
		589
		590	=item * Condition variables are like "Merge Points" - points in your program
		591	where you merge multiple independent results/control flows into one.
		592
		593	=item * Condition variables represent a transaction - functions that start
		594	some kind of transaction can return them, leaving the caller the choice
		595	between waiting in a blocking fashion, or setting a callback.
		596
		597	=item * Condition variables represent future values, or promises to deliver
		598	some result, long before the result is available.
		599
		600	=back
515		601
516	Condition variables are very useful to signal that something has finished,	602	Condition variables are very useful to signal that something has finished,
517	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,
518	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
519	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
…		…
532		618
533	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
534	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
535	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
536	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
537	it's C<new> method in your own C<new> method.	623	its C<new> method in your own C<new> method.
538		624
539	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
540	eventually calls C<< -> send >>, and the "consumer side", which waits	626	eventually calls C<< -> send >>, and the "consumer side", which waits
541	for the send to occur.	627	for the send to occur.
542		628
543	Example: wait for a timer.	629	Example: wait for a timer.
544		630
545	# wait till the result is ready	631	# condition: "wait till the timer is fired"
546	my $result_ready = AnyEvent->condvar;	632	my $timer_fired = AnyEvent->condvar;
547		633
548	# do something such as adding a timer	634	# create the timer - we could wait for, say
549	# or socket watcher the calls $result_ready->send	635	# a handle becomign ready, or even an
550	# when the "result" is ready.	636	# AnyEvent::HTTP request to finish, but
551	# in this case, we simply use a timer:	637	# in this case, we simply use a timer:
552	my $w = AnyEvent->timer (	638	my $w = AnyEvent->timer (
553	after => 1,	639	after => 1,
554	cb => sub { $result_ready->send },	640	cb => sub { $timer_fired->send },
555	);	641	);
556		642
557	# this "blocks" (while handling events) till the callback	643	# this "blocks" (while handling events) till the callback
558	# calls send	644	# calls ->send
559	$result_ready->recv;	645	$timer_fired->recv;
560		646
561	Example: wait for a timer, but take advantage of the fact that	647	Example: wait for a timer, but take advantage of the fact that condition
562	condition variables are also code references.	648	variables are also callable directly.
563		649
564	my $done = AnyEvent->condvar;	650	my $done = AnyEvent->condvar;
565	my $delay = AnyEvent->timer (after => 5, cb => $done);	651	my $delay = AnyEvent->timer (after => 5, cb => $done);
566	$done->recv;	652	$done->recv;
567		653
…		…
573		659
574	...	660	...
575		661
576	my @info = $couchdb->info->recv;	662	my @info = $couchdb->info->recv;
577		663
578	And this is how you would just ste a callback to be called whenever the	664	And this is how you would just set a callback to be called whenever the
579	results are available:	665	results are available:
580		666
581	$couchdb->info->cb (sub {	667	$couchdb->info->cb (sub {
582	my @info = $_[0]->recv;	668	my @info = $_[0]->recv;
583	});	669	});
…		…
601	immediately from within send.	687	immediately from within send.
602		688
603	Any arguments passed to the C<send> call will be returned by all	689	Any arguments passed to the C<send> call will be returned by all
604	future C<< ->recv >> calls.	690	future C<< ->recv >> calls.
605		691
606	Condition variables are overloaded so one can call them directly	692	Condition variables are overloaded so one can call them directly (as if
607	(as a code reference). Calling them directly is the same as calling	693	they were a code reference). Calling them directly is the same as calling
608	C<send>. Note, however, that many C-based event loops do not handle	694	C<send>.
609	overloading, so as tempting as it may be, passing a condition variable
610	instead of a callback does not work. Both the pure perl and EV loops
611	support overloading, however, as well as all functions that use perl to
612	invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
613	example).
614		695
615	=item $cv->croak ($error)	696	=item $cv->croak ($error)
616		697
617	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
618	C<Carp::croak> with the given error message/object/scalar.	699	C<Carp::croak> with the given error message/object/scalar.
619		700
620	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
621	user/consumer.	702	user/consumer. Doing it this way instead of calling C<croak> directly
		703	delays the error detection, but has the overwhelming advantage that it
		704	diagnoses the error at the place where the result is expected, and not
		705	deep in some event callback with no connection to the actual code causing
		706	the problem.
622		707
623	=item $cv->begin ([group callback])	708	=item $cv->begin ([group callback])
624		709
625	=item $cv->end	710	=item $cv->end
626		711
…		…
628	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
629	to use a condition variable for the whole process.	714	to use a condition variable for the whole process.
630		715
631	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
632	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
633	>>, 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
634	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
635	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.
636		722
637	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
638	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
639	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).
640		726
…		…
662	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
663	sending.	749	sending.
664		750
665	The ping example mentioned above is slightly more complicated, as the	751	The ping example mentioned above is slightly more complicated, as the
666	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
667	begung can potentially be zero:	753	begun can potentially be zero:
668		754
669	my $cv = AnyEvent->condvar;	755	my $cv = AnyEvent->condvar;
670		756
671	my %result;	757	my %result;
672	$cv->begin (sub { $cv->send (\%result) });	758	$cv->begin (sub { shift->send (\%result) });
673		759
674	for my $host (@list_of_hosts) {	760	for my $host (@list_of_hosts) {
675	$cv->begin;	761	$cv->begin;
676	ping_host_then_call_callback $host, sub {	762	ping_host_then_call_callback $host, sub {
677	$result{$host} = ...;	763	$result{$host} = ...;
…		…
693	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
694	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
695	doesn't execute once).	781	doesn't execute once).
696		782
697	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
698	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
699	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
700	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,
701	call C<end>.	787	call C<end>.
702		788
703	=back	789	=back
…		…
710	=over 4	796	=over 4
711		797
712	=item $cv->recv	798	=item $cv->recv
713		799
714	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak	800	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
715	>> methods have been called on c<$cv>, while servicing other watchers	801	>> methods have been called on C<$cv>, while servicing other watchers
716	normally.	802	normally.
717		803
718	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
719	will return immediately.	805	will return immediately.
720		806
…		…
722	function will call C<croak>.	808	function will call C<croak>.
723		809
724	In list context, all parameters passed to C<send> will be returned,	810	In list context, all parameters passed to C<send> will be returned,
725	in scalar context only the first one will be returned.	811	in scalar context only the first one will be returned.
726		812
		813	Note that doing a blocking wait in a callback is not supported by any
		814	event loop, that is, recursive invocation of a blocking C<< ->recv
		815	>> is not allowed, and the C<recv> call will C<croak> if such a
		816	condition is detected. This condition can be slightly loosened by using
		817	L<Coro::AnyEvent>, which allows you to do a blocking C<< ->recv >> from
		818	any thread that doesn't run the event loop itself.
		819
727	Not all event models support a blocking wait - some die in that case	820	Not all event models support a blocking wait - some die in that case
728	(programs might want to do that to stay interactive), so I<if you are	821	(programs might want to do that to stay interactive), so I<if you are
729	using this from a module, never require a blocking wait>, but let the	822	using this from a module, never require a blocking wait>. Instead, let the
730	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
731	condition variables with some kind of request results and supporting	824	condition variables with some kind of request results and supporting
732	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,
733	while still supporting blocking waits if the caller so desires).	826	while still supporting blocking waits if the caller so desires).
734		827
735	Another reason I<never> to C<< ->recv >> in a module is that you cannot
736	sensibly have two C<< ->recv >>'s in parallel, as that would require
737	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
738	can supply.
739
740	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
741	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
742	versions and also integrates coroutines into AnyEvent, making blocking
743	C<< ->recv >> calls perfectly safe as long as they are done from another
744	coroutine (one that doesn't run the event loop).
745
746	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
747	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
748	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
749	waits otherwise.	831	waits otherwise.
750		832
751	=item $bool = $cv->ready	833	=item $bool = $cv->ready
…		…
757		839
758	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
759	replaces it before doing so.	841	replaces it before doing so.
760		842
761	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
762	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
763	variable itself. Calling C<recv> inside the callback or at any later time	845	condition variable itself. If the condition is already true, the
764	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.
765		848
766	=back	849	=back
767		850
		851	=head1 SUPPORTED EVENT LOOPS/BACKENDS
		852
		853	The available backend classes are (every class has its own manpage):
		854
		855	=over 4
		856
		857	=item Backends that are autoprobed when no other event loop can be found.
		858
		859	EV is the preferred backend when no other event loop seems to be in
		860	use. If EV is not installed, then AnyEvent will fall back to its own
		861	pure-perl implementation, which is available everywhere as it comes with
		862	AnyEvent itself.
		863
		864	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
		865	AnyEvent::Impl::Perl pure-perl AnyEvent::Loop, fast and portable.
		866
		867	=item Backends that are transparently being picked up when they are used.
		868
		869	These will be used if they are already loaded when the first watcher
		870	is created, in which case it is assumed that the application is using
		871	them. This means that AnyEvent will automatically pick the right backend
		872	when the main program loads an event module before anything starts to
		873	create watchers. Nothing special needs to be done by the main program.
		874
		875	AnyEvent::Impl::Event based on Event, very stable, few glitches.
		876	AnyEvent::Impl::Glib based on Glib, slow but very stable.
		877	AnyEvent::Impl::Tk based on Tk, very broken.
		878	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
		879	AnyEvent::Impl::POE based on POE, very slow, some limitations.
		880	AnyEvent::Impl::Irssi used when running within irssi.
		881	AnyEvent::Impl::IOAsync based on IO::Async.
		882	AnyEvent::Impl::Cocoa based on Cocoa::EventLoop.
		883	AnyEvent::Impl::FLTK2 based on FLTK (fltk 2 binding).
		884
		885	=item Backends with special needs.
		886
		887	Qt requires the Qt::Application to be instantiated first, but will
		888	otherwise be picked up automatically. As long as the main program
		889	instantiates the application before any AnyEvent watchers are created,
		890	everything should just work.
		891
		892	AnyEvent::Impl::Qt based on Qt.
		893
		894	=item Event loops that are indirectly supported via other backends.
		895
		896	Some event loops can be supported via other modules:
		897
		898	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
		899
		900	B<WxWidgets> has no support for watching file handles. However, you can
		901	use WxWidgets through the POE adaptor, as POE has a Wx backend that simply
		902	polls 20 times per second, which was considered to be too horrible to even
		903	consider for AnyEvent.
		904
		905	B<Prima> is not supported as nobody seems to be using it, but it has a POE
		906	backend, so it can be supported through POE.
		907
		908	AnyEvent knows about both L<Prima> and L<Wx>, however, and will try to
		909	load L<POE> when detecting them, in the hope that POE will pick them up,
		910	in which case everything will be automatic.
		911
		912	=back
		913
768	=head1 GLOBAL VARIABLES AND FUNCTIONS	914	=head1 GLOBAL VARIABLES AND FUNCTIONS
769		915
		916	These are not normally required to use AnyEvent, but can be useful to
		917	write AnyEvent extension modules.
		918
770	=over 4	919	=over 4
771		920
772	=item $AnyEvent::MODEL	921	=item $AnyEvent::MODEL
773		922
774	Contains C<undef> until the first watcher is being created. Then it	923	Contains C<undef> until the first watcher is being created, before the
		924	backend has been autodetected.
		925
775	contains the event model that is being used, which is the name of the	926	Afterwards it contains the event model that is being used, which is the
776	Perl class implementing the model. This class is usually one of the	927	name of the Perl class implementing the model. This class is usually one
777	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	928	of the C<AnyEvent::Impl::xxx> modules, but can be any other class in the
778	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	929	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
779		930	will be C<urxvt::anyevent>).
780	The known classes so far are:
781
782	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
783	AnyEvent::Impl::Event based on Event, second best choice.
784	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
785	AnyEvent::Impl::Glib based on Glib, third-best choice.
786	AnyEvent::Impl::Tk based on Tk, very bad choice.
787	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
788	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
789	AnyEvent::Impl::POE based on POE, not generic enough for full support.
790
791	# warning, support for IO::Async is only partial, as it is too broken
792	# and limited toe ven support the AnyEvent API. See AnyEvent::Impl::Async.
793	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed (see its docs).
794
795	There is no support for WxWidgets, as WxWidgets has no support for
796	watching file handles. However, you can use WxWidgets through the
797	POE Adaptor, as POE has a Wx backend that simply polls 20 times per
798	second, which was considered to be too horrible to even consider for
799	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
800	it's adaptor.
801
802	AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
803	autodetecting them.
804		931
805	=item AnyEvent::detect	932	=item AnyEvent::detect
806		933
807	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	934	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
808	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
809	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
810	runtime.	937	runtime, and not e.g. during initialisation of your module.
		938
		939	If you need to do some initialisation before AnyEvent watchers are
		940	created, use C<post_detect>.
811		941
812	=item $guard = AnyEvent::post_detect { BLOCK }	942	=item $guard = AnyEvent::post_detect { BLOCK }
813		943
814	Arranges for the code block to be executed as soon as the event model is	944	Arranges for the code block to be executed as soon as the event model is
815	autodetected (or immediately if this has already happened).	945	autodetected (or immediately if that has already happened).
		946
		947	The block will be executed I<after> the actual backend has been detected
		948	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
		949	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
		950	other initialisations - see the sources of L<AnyEvent::Strict> or
		951	L<AnyEvent::AIO> to see how this is used.
		952
		953	The most common usage is to create some global watchers, without forcing
		954	event module detection too early, for example, L<AnyEvent::AIO> creates
		955	and installs the global L<IO::AIO> watcher in a C<post_detect> block to
		956	avoid autodetecting the event module at load time.
816		957
817	If called in scalar or list context, then it creates and returns an object	958	If called in scalar or list context, then it creates and returns an object
818	that automatically removes the callback again when it is destroyed. See	959	that automatically removes the callback again when it is destroyed (or
		960	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
819	L<Coro::BDB> for a case where this is useful.	961	a case where this is useful.
		962
		963	Example: Create a watcher for the IO::AIO module and store it in
		964	C<$WATCHER>, but do so only do so after the event loop is initialised.
		965
		966	our WATCHER;
		967
		968	my $guard = AnyEvent::post_detect {
		969	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
		970	};
		971
		972	# the ||= is important in case post_detect immediately runs the block,
		973	# as to not clobber the newly-created watcher. assigning both watcher and
		974	# post_detect guard to the same variable has the advantage of users being
		975	# able to just C<undef $WATCHER> if the watcher causes them grief.
		976
		977	$WATCHER ||= $guard;
820		978
821	=item @AnyEvent::post_detect	979	=item @AnyEvent::post_detect
822		980
823	If there are any code references in this array (you can C<push> to it	981	If there are any code references in this array (you can C<push> to it
824	before or after loading AnyEvent), then they will called directly after	982	before or after loading AnyEvent), then they will be called directly
825	the event loop has been chosen.	983	after the event loop has been chosen.
826		984
827	You should check C<$AnyEvent::MODEL> before adding to this array, though:	985	You should check C<$AnyEvent::MODEL> before adding to this array, though:
828	if it contains a true value then the event loop has already been detected,	986	if it is defined then the event loop has already been detected, and the
829	and the array will be ignored.	987	array will be ignored.
830		988
831	Best use C<AnyEvent::post_detect { BLOCK }> instead.	989	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
		990	it, as it takes care of these details.
		991
		992	This variable is mainly useful for modules that can do something useful
		993	when AnyEvent is used and thus want to know when it is initialised, but do
		994	not need to even load it by default. This array provides the means to hook
		995	into AnyEvent passively, without loading it.
		996
		997	Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used
		998	together, you could put this into Coro (this is the actual code used by
		999	Coro to accomplish this):
		1000
		1001	if (defined $AnyEvent::MODEL) {
		1002	# AnyEvent already initialised, so load Coro::AnyEvent
		1003	require Coro::AnyEvent;
		1004	} else {
		1005	# AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
		1006	# as soon as it is
		1007	push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
		1008	}
		1009
		1010	=item AnyEvent::postpone { BLOCK }
		1011
		1012	Arranges for the block to be executed as soon as possible, but not before
		1013	the call itself returns. In practise, the block will be executed just
		1014	before the event loop polls for new events, or shortly afterwards.
		1015
		1016	This function never returns anything (to make the C<return postpone { ...
		1017	}> idiom more useful.
		1018
		1019	To understand the usefulness of this function, consider a function that
		1020	asynchronously does something for you and returns some transaction
		1021	object or guard to let you cancel the operation. For example,
		1022	C<AnyEvent::Socket::tcp_connect>:
		1023
		1024	# start a conenction attempt unless one is active
		1025	$self->{connect_guard} ||= AnyEvent::Socket::tcp_connect "www.example.net", 80, sub {
		1026	delete $self->{connect_guard};
		1027	...
		1028	};
		1029
		1030	Imagine that this function could instantly call the callback, for
		1031	example, because it detects an obvious error such as a negative port
		1032	number. Invoking the callback before the function returns causes problems
		1033	however: the callback will be called and will try to delete the guard
		1034	object. But since the function hasn't returned yet, there is nothing to
		1035	delete. When the function eventually returns it will assign the guard
		1036	object to C<< $self->{connect_guard} >>, where it will likely never be
		1037	deleted, so the program thinks it is still trying to connect.
		1038
		1039	This is where C<AnyEvent::postpone> should be used. Instead of calling the
		1040	callback directly on error:
		1041
		1042	$cb->(undef), return # signal error to callback, BAD!
		1043	if $some_error_condition;
		1044
		1045	It should use C<postpone>:
		1046
		1047	AnyEvent::postpone { $cb->(undef) }, return # signal error to callback, later
		1048	if $some_error_condition;
832		1049
833	=back	1050	=back
834		1051
835	=head1 WHAT TO DO IN A MODULE	1052	=head1 WHAT TO DO IN A MODULE
836		1053
…		…
847	because it will stall the whole program, and the whole point of using	1064	because it will stall the whole program, and the whole point of using
848	events is to stay interactive.	1065	events is to stay interactive.
849		1066
850	It is fine, however, to call C<< ->recv >> when the user of your module	1067	It is fine, however, to call C<< ->recv >> when the user of your module
851	requests it (i.e. if you create a http request object ad have a method	1068	requests it (i.e. if you create a http request object ad have a method
852	called C<results> that returns the results, it should call C<< ->recv >>	1069	called C<results> that returns the results, it may call C<< ->recv >>
853	freely, as the user of your module knows what she is doing. always).	1070	freely, as the user of your module knows what she is doing. Always).
854		1071
855	=head1 WHAT TO DO IN THE MAIN PROGRAM	1072	=head1 WHAT TO DO IN THE MAIN PROGRAM
856		1073
857	There will always be a single main program - the only place that should	1074	There will always be a single main program - the only place that should
858	dictate which event model to use.	1075	dictate which event model to use.
859		1076
860	If it doesn't care, it can just "use AnyEvent" and use it itself, or not	1077	If the program is not event-based, it need not do anything special, even
861	do anything special (it does not need to be event-based) and let AnyEvent	1078	when it depends on a module that uses an AnyEvent. If the program itself
862	decide which implementation to chose if some module relies on it.	1079	uses AnyEvent, but does not care which event loop is used, all it needs
		1080	to do is C<use AnyEvent>. In either case, AnyEvent will choose the best
		1081	available loop implementation.
863		1082
864	If the main program relies on a specific event model - for example, in	1083	If the main program relies on a specific event model - for example, in
865	Gtk2 programs you have to rely on the Glib module - you should load the	1084	Gtk2 programs you have to rely on the Glib module - you should load the
866	event module before loading AnyEvent or any module that uses it: generally	1085	event module before loading AnyEvent or any module that uses it: generally
867	speaking, you should load it as early as possible. The reason is that	1086	speaking, you should load it as early as possible. The reason is that
868	modules might create watchers when they are loaded, and AnyEvent will	1087	modules might create watchers when they are loaded, and AnyEvent will
869	decide on the event model to use as soon as it creates watchers, and it	1088	decide on the event model to use as soon as it creates watchers, and it
870	might chose the wrong one unless you load the correct one yourself.	1089	might choose the wrong one unless you load the correct one yourself.
871		1090
872	You can chose to use a pure-perl implementation by loading the	1091	You can chose to use a pure-perl implementation by loading the
873	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour	1092	C<AnyEvent::Loop> module, which gives you similar behaviour
874	everywhere, but letting AnyEvent chose the model is generally better.	1093	everywhere, but letting AnyEvent chose the model is generally better.
875		1094
876	=head2 MAINLOOP EMULATION	1095	=head2 MAINLOOP EMULATION
877		1096
878	Sometimes (often for short test scripts, or even standalone programs who	1097	Sometimes (often for short test scripts, or even standalone programs who
…		…
891		1110
892		1111
893	=head1 OTHER MODULES	1112	=head1 OTHER MODULES
894		1113
895	The following is a non-exhaustive list of additional modules that use	1114	The following is a non-exhaustive list of additional modules that use
896	AnyEvent and can therefore be mixed easily with other AnyEvent modules	1115	AnyEvent as a client and can therefore be mixed easily with other AnyEvent
897	in the same program. Some of the modules come with AnyEvent, some are	1116	modules and other event loops in the same program. Some of the modules
898	available via CPAN.	1117	come as part of AnyEvent, the others are available via CPAN.
899		1118
900	=over 4	1119	=over 4
901		1120
902	=item L<AnyEvent::Util>	1121	=item L<AnyEvent::Util>
903		1122
904	Contains various utility functions that replace often-used but blocking	1123	Contains various utility functions that replace often-used blocking
905	functions such as C<inet_aton> by event-/callback-based versions.	1124	functions such as C<inet_aton> with event/callback-based versions.
906		1125
907	=item L<AnyEvent::Socket>	1126	=item L<AnyEvent::Socket>
908		1127
909	Provides various utility functions for (internet protocol) sockets,	1128	Provides various utility functions for (internet protocol) sockets,
910	addresses and name resolution. Also functions to create non-blocking tcp	1129	addresses and name resolution. Also functions to create non-blocking tcp
…		…
912		1131
913	=item L<AnyEvent::Handle>	1132	=item L<AnyEvent::Handle>
914		1133
915	Provide read and write buffers, manages watchers for reads and writes,	1134	Provide read and write buffers, manages watchers for reads and writes,
916	supports raw and formatted I/O, I/O queued and fully transparent and	1135	supports raw and formatted I/O, I/O queued and fully transparent and
917	non-blocking SSL/TLS.	1136	non-blocking SSL/TLS (via L<AnyEvent::TLS>).
918		1137
919	=item L<AnyEvent::DNS>	1138	=item L<AnyEvent::DNS>
920		1139
921	Provides rich asynchronous DNS resolver capabilities.	1140	Provides rich asynchronous DNS resolver capabilities.
922		1141
		1142	=item L<AnyEvent::HTTP>, L<AnyEvent::IRC>, L<AnyEvent::XMPP>, L<AnyEvent::GPSD>, L<AnyEvent::IGS>, L<AnyEvent::FCP>
		1143
		1144	Implement event-based interfaces to the protocols of the same name (for
		1145	the curious, IGS is the International Go Server and FCP is the Freenet
		1146	Client Protocol).
		1147
		1148	=item L<AnyEvent::Handle::UDP>
		1149
		1150	Here be danger!
		1151
		1152	As Pauli would put it, "Not only is it not right, it's not even wrong!" -
		1153	there are so many things wrong with AnyEvent::Handle::UDP, most notably
		1154	its use of a stream-based API with a protocol that isn't streamable, that
		1155	the only way to improve it is to delete it.
		1156
		1157	It features data corruption (but typically only under load) and general
		1158	confusion. On top, the author is not only clueless about UDP but also
		1159	fact-resistant - some gems of his understanding: "connect doesn't work
		1160	with UDP", "UDP packets are not IP packets", "UDP only has datagrams, not
		1161	packets", "I don't need to implement proper error checking as UDP doesn't
		1162	support error checking" and so on - he doesn't even understand what's
		1163	wrong with his module when it is explained to him.
		1164
923	=item L<AnyEvent::HTTP>	1165	=item L<AnyEvent::DBI>
924		1166
925	A simple-to-use HTTP library that is capable of making a lot of concurrent	1167	Executes L<DBI> requests asynchronously in a proxy process for you,
926	HTTP requests.	1168	notifying you in an event-based way when the operation is finished.
		1169
		1170	=item L<AnyEvent::AIO>
		1171
		1172	Truly asynchronous (as opposed to non-blocking) I/O, should be in the
		1173	toolbox of every event programmer. AnyEvent::AIO transparently fuses
		1174	L<IO::AIO> and AnyEvent together, giving AnyEvent access to event-based
		1175	file I/O, and much more.
927		1176
928	=item L<AnyEvent::HTTPD>	1177	=item L<AnyEvent::HTTPD>
929		1178
930	Provides a simple web application server framework.	1179	A simple embedded webserver.
931		1180
932	=item L<AnyEvent::FastPing>	1181	=item L<AnyEvent::FastPing>
933		1182
934	The fastest ping in the west.	1183	The fastest ping in the west.
935		1184
936	=item L<AnyEvent::DBI>
937
938	Executes L<DBI> requests asynchronously in a proxy process.
939
940	=item L<AnyEvent::AIO>
941
942	Truly asynchronous I/O, should be in the toolbox of every event
943	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
944	together.
945
946	=item L<AnyEvent::BDB>
947
948	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
949	L<BDB> and AnyEvent together.
950
951	=item L<AnyEvent::GPSD>
952
953	A non-blocking interface to gpsd, a daemon delivering GPS information.
954
955	=item L<AnyEvent::IGS>
956
957	A non-blocking interface to the Internet Go Server protocol (used by
958	L<App::IGS>).
959
960	=item L<AnyEvent::IRC>
961
962	AnyEvent based IRC client module family (replacing the older Net::IRC3).
963
964	=item L<Net::XMPP2>
965
966	AnyEvent based XMPP (Jabber protocol) module family.
967
968	=item L<Net::FCP>
969
970	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
971	of AnyEvent.
972
973	=item L<Event::ExecFlow>
974
975	High level API for event-based execution flow control.
976
977	=item L<Coro>	1185	=item L<Coro>
978		1186
979	Has special support for AnyEvent via L<Coro::AnyEvent>.	1187	Has special support for AnyEvent via L<Coro::AnyEvent>.
980		1188
981	=item L<IO::Lambda>
982
983	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
984
985	=back	1189	=back
986		1190
987	=cut	1191	=cut
988		1192
989	package AnyEvent;	1193	package AnyEvent;
990		1194
991	no warnings;	1195	# basically a tuned-down version of common::sense
992	use strict qw(vars subs);	1196	sub common_sense {
		1197	# from common:.sense 3.4
		1198	${^WARNING_BITS} ^= ${^WARNING_BITS} ^ "\x3c\x3f\x33\x00\x0f\xf0\x0f\xc0\xf0\xfc\x33\x00";
		1199	# use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)
		1200	$^H |= 0x00000600;
		1201	}
993		1202
		1203	BEGIN { AnyEvent::common_sense }
		1204
994	use Carp;	1205	use Carp ();
995		1206
996	our $VERSION = 4.8;	1207	our $VERSION = '5.34';
997	our $MODEL;	1208	our $MODEL;
998		1209
999	our $AUTOLOAD;	1210	our $AUTOLOAD;
1000	our @ISA;	1211	our @ISA;
1001		1212
1002	our @REGISTRY;	1213	our @REGISTRY;
1003		1214
1004	our $WIN32;	1215	our $VERBOSE;
1005		1216
1006	BEGIN {	1217	BEGIN {
1007	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";	1218	require "AnyEvent/constants.pl";
		1219
1008	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";	1220	eval "sub TAINT (){" . (${^TAINT}*1) . "}";
1009		1221
1010	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}	1222	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
1011	if ${^TAINT};	1223	if ${^TAINT};
1012	}
1013		1224
1014	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1225	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
		1226
		1227	}
		1228
		1229	our $MAX_SIGNAL_LATENCY = 10;
1015		1230
1016	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred	1231	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
1017		1232
1018	{	1233	{
1019	my $idx;	1234	my $idx;
1020	$PROTOCOL{$_} = ++$idx	1235	$PROTOCOL{$_} = ++$idx
1021	for reverse split /\s*,\s*/,	1236	for reverse split /\s*,\s*/,
1022	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1237	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
1023	}	1238	}
1024		1239
		1240	our @post_detect;
		1241
		1242	sub post_detect(&) {
		1243	my ($cb) = @_;
		1244
		1245	push @post_detect, $cb;
		1246
		1247	defined wantarray
		1248	? bless \$cb, "AnyEvent::Util::postdetect"
		1249	: ()
		1250	}
		1251
		1252	sub AnyEvent::Util::postdetect::DESTROY {
		1253	@post_detect = grep $_ != ${$_[0]}, @post_detect;
		1254	}
		1255
		1256	our $POSTPONE_W;
		1257	our @POSTPONE;
		1258
		1259	sub _postpone_exec {
		1260	undef $POSTPONE_W;
		1261
		1262	&{ shift @POSTPONE }
		1263	while @POSTPONE;
		1264	}
		1265
		1266	sub postpone(&) {
		1267	push @POSTPONE, shift;
		1268
		1269	$POSTPONE_W ||= AE::timer (0, 0, \&_postpone_exec);
		1270
		1271	()
		1272	}
		1273
1025	my @models = (	1274	our @models = (
1026	[EV:: => AnyEvent::Impl::EV::],	1275	[EV:: => AnyEvent::Impl::EV:: , 1],
1027	[Event:: => AnyEvent::Impl::Event::],	1276	[AnyEvent::Loop:: => AnyEvent::Impl::Perl:: , 1],
1028	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
1029	# everything below here will not be autoprobed	1277	# everything below here will not (normally) be autoprobed
1030	# as the pureperl backend should work everywhere	1278	# as the pure perl backend should work everywhere
1031	# and is usually faster	1279	# and is usually faster
		1280	[Event:: => AnyEvent::Impl::Event::, 1],
		1281	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
		1282	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
		1283	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
1032	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1284	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
1033	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
1034	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
1035	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1285	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
1036	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1286	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
1037	[Wx:: => AnyEvent::Impl::POE::],	1287	[Wx:: => AnyEvent::Impl::POE::],
1038	[Prima:: => AnyEvent::Impl::POE::],	1288	[Prima:: => AnyEvent::Impl::POE::],
1039	# IO::Async is just too broken - we would need workaorunds for its	1289	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # a bitch to autodetect
1040	# byzantine signal and broken child handling, among others.	1290	[Cocoa::EventLoop:: => AnyEvent::Impl::Cocoa::],
1041	# IO::Async is rather hard to detect, as it doesn't have any	1291	[FLTK:: => AnyEvent::Impl::FLTK2::],
1042	# obvious default class.
1043	# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
1044	# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
1045	# [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
1046	);	1292	);
1047		1293
1048	our %method = map +($_ => 1),
1049	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
1050
1051	our @post_detect;
1052
1053	sub post_detect(&) {	1294	sub detect() {
1054	my ($cb) = @_;	1295	# free some memory
		1296	*detect = sub () { $MODEL };
1055		1297
1056	if ($MODEL) {	1298	local $!; # for good measure
1057	$cb->();	1299	local $SIG{__DIE__};
1058		1300
1059	1	1301	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z0-9:]+)$/) {
		1302	my $model = $1;
		1303	$model = "AnyEvent::Impl::$model" unless $model =~ s/::$//;
		1304	if (eval "require $model") {
		1305	$MODEL = $model;
		1306	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
1060	} else {	1307	} else {
1061	push @post_detect, $cb;	1308	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
1062		1309	}
1063	defined wantarray
1064	? bless \$cb, "AnyEvent::Util::postdetect"
1065	: ()
1066	}	1310	}
1067	}
1068		1311
1069	sub AnyEvent::Util::postdetect::DESTROY {	1312	# check for already loaded models
1070	@post_detect = grep $_ != ${$_[0]}, @post_detect;
1071	}
1072
1073	sub detect() {
1074	unless ($MODEL) {	1313	unless ($MODEL) {
1075	no strict 'refs';	1314	for (@REGISTRY, @models) {
1076	local $SIG{__DIE__};	1315	my ($package, $model) = @$_;
1077		1316	if (${"$package\::VERSION"} > 0) {
1078	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
1079	my $model = "AnyEvent::Impl::$1";
1080	if (eval "require $model") {	1317	if (eval "require $model") {
1081	$MODEL = $model;	1318	$MODEL = $model;
1082	warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1;	1319	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1083	} else {	1320	last;
1084	warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose;	1321	}
1085	}	1322	}
1086	}	1323	}
1087		1324
1088	# check for already loaded models
1089	unless ($MODEL) {	1325	unless ($MODEL) {
		1326	# try to autoload a model
1090	for (@REGISTRY, @models) {	1327	for (@REGISTRY, @models) {
1091	my ($package, $model) = @$_;	1328	my ($package, $model, $autoload) = @$_;
		1329	if (
		1330	$autoload
		1331	and eval "require $package"
1092	if (${"$package\::VERSION"} > 0) {	1332	and ${"$package\::VERSION"} > 0
1093	if (eval "require $model") {	1333	and eval "require $model"
		1334	) {
1094	$MODEL = $model;	1335	$MODEL = $model;
1095	warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1;	1336	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
1096	last;	1337	last;
1097	}
1098	}	1338	}
1099	}	1339	}
1100		1340
1101	unless ($MODEL) {
1102	# try to load a model
1103
1104	for (@REGISTRY, @models) {
1105	my ($package, $model) = @$_;
1106	if (eval "require $package"
1107	and ${"$package\::VERSION"} > 0
1108	and eval "require $model") {
1109	$MODEL = $model;
1110	warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1;
1111	last;
1112	}
1113	}
1114
1115	$MODEL	1341	$MODEL
1116	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";	1342	or die "AnyEvent: backend autodetection failed - did you properly install AnyEvent?\n";
1117	}
1118	}	1343	}
1119
1120	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1121
1122	unshift @ISA, $MODEL;
1123
1124	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
1125
1126	(shift @post_detect)->() while @post_detect;
1127	}	1344	}
1128		1345
		1346	# free memory only needed for probing
		1347	undef @models;
		1348	undef @REGISTRY;
		1349
		1350	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1351	unshift @ISA, $MODEL;
		1352
		1353	# now nuke some methods that are overridden by the backend.
		1354	# SUPER usage is not allowed in these.
		1355	for (qw(time signal child idle)) {
		1356	undef &{"AnyEvent::Base::$_"}
		1357	if defined &{"$MODEL\::$_"};
		1358	}
		1359
		1360	if ($ENV{PERL_ANYEVENT_STRICT}) {
		1361	eval { require AnyEvent::Strict };
		1362	warn "AnyEvent: cannot load AnyEvent::Strict: $@"
		1363	if $@ && $VERBOSE;
		1364	}
		1365
		1366	(shift @post_detect)->() while @post_detect;
		1367	undef @post_detect;
		1368
		1369	*post_detect = sub(&) {
		1370	shift->();
		1371
		1372	undef
		1373	};
		1374
		1375	# recover a few more bytes
		1376	postpone {
		1377	undef &AUTOLOAD;
		1378	};
		1379
1129	$MODEL	1380	$MODEL
1130	}	1381	}
		1382
		1383	our %method = map +($_ => 1),
		1384	qw(io timer time now now_update signal child idle condvar DESTROY);
1131		1385
1132	sub AUTOLOAD {	1386	sub AUTOLOAD {
1133	(my $func = $AUTOLOAD) =~ s/.*://;	1387	(my $func = $AUTOLOAD) =~ s/.*://;
1134		1388
1135	$method{$func}	1389	$method{$func}
1136	or croak "$func: not a valid method for AnyEvent objects";	1390	or Carp::croak "$func: not a valid AnyEvent class method";
1137		1391
1138	detect unless $MODEL;	1392	# free some memory
		1393	undef %method;
		1394
		1395	detect;
1139		1396
1140	my $class = shift;	1397	my $class = shift;
1141	$class->$func (@_);	1398	$class->$func (@_);
1142	}	1399	}
1143		1400
…		…
1146	# allow only one watcher per fd, so we dup it to get a different one).	1403	# allow only one watcher per fd, so we dup it to get a different one).
1147	sub _dupfh($$;$$) {	1404	sub _dupfh($$;$$) {
1148	my ($poll, $fh, $r, $w) = @_;	1405	my ($poll, $fh, $r, $w) = @_;
1149		1406
1150	# cygwin requires the fh mode to be matching, unix doesn't	1407	# cygwin requires the fh mode to be matching, unix doesn't
1151	my ($rw, $mode) = $poll eq "r" ? ($r, "<")	1408	my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1152	: $poll eq "w" ? ($w, ">")
1153	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1154		1409
1155	open my $fh2, "$mode&" . fileno $fh	1410	open my $fh2, $mode, $fh
1156	or die "cannot dup() filehandle: $!,";	1411	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1157		1412
1158	# we assume CLOEXEC is already set by perl in all important cases	1413	# we assume CLOEXEC is already set by perl in all important cases
1159		1414
1160	($fh2, $rw)	1415	($fh2, $rw)
1161	}	1416	}
1162		1417
		1418	=head1 SIMPLIFIED AE API
		1419
		1420	Starting with version 5.0, AnyEvent officially supports a second, much
		1421	simpler, API that is designed to reduce the calling, typing and memory
		1422	overhead by using function call syntax and a fixed number of parameters.
		1423
		1424	See the L<AE> manpage for details.
		1425
		1426	=cut
		1427
		1428	package AE;
		1429
		1430	our $VERSION = $AnyEvent::VERSION;
		1431
		1432
		1433	sub _reset() {
		1434	eval q{
		1435	# fall back to the main API by default - backends and AnyEvent::Base
		1436	# implementations can overwrite these.
		1437
		1438	sub io($$$) {
		1439	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
		1440	}
		1441
		1442	sub timer($$$) {
		1443	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
		1444	}
		1445
		1446	sub signal($$) {
		1447	AnyEvent->signal (signal => $_[0], cb => $_[1])
		1448	}
		1449
		1450	sub child($$) {
		1451	AnyEvent->child (pid => $_[0], cb => $_[1])
		1452	}
		1453
		1454	sub idle($) {
		1455	AnyEvent->idle (cb => $_[0])
		1456	}
		1457
		1458	sub cv(;&) {
		1459	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
		1460	}
		1461
		1462	sub now() {
		1463	AnyEvent->now
		1464	}
		1465
		1466	sub now_update() {
		1467	AnyEvent->now_update
		1468	}
		1469
		1470	sub time() {
		1471	AnyEvent->time
		1472	}
		1473
		1474	*postpone = \&AnyEvent::postpone;
		1475	};
		1476	die if $@;
		1477	}
		1478
		1479	BEGIN { _reset }
		1480
1163	package AnyEvent::Base;	1481	package AnyEvent::Base;
1164		1482
1165	# default implementations for many methods	1483	# default implementations for many methods
1166		1484
1167	BEGIN {	1485	sub time {
		1486	eval q{ # poor man's autoloading {}
		1487	# probe for availability of Time::HiRes
1168	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {	1488	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1489	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1169	*_time = \&Time::HiRes::time;	1490	*AE::time = \&Time::HiRes::time;
1170	# if (eval "use POSIX (); (POSIX::times())...	1491	# if (eval "use POSIX (); (POSIX::times())...
1171	} else {	1492	} else {
		1493	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1172	*_time = sub { time }; # epic fail	1494	*AE::time = sub (){ time }; # epic fail
		1495	}
		1496
		1497	*time = sub { AE::time }; # different prototypes
		1498	};
		1499	die if $@;
		1500
		1501	&time
		1502	}
		1503
		1504	*now = \&time;
		1505
		1506	sub now_update { }
		1507
		1508	sub _poll {
		1509	Carp::croak "$AnyEvent::MODEL does not support blocking waits. Caught";
		1510	}
		1511
		1512	# default implementation for ->condvar
		1513	# in fact, the default should not be overwritten
		1514
		1515	sub condvar {
		1516	eval q{ # poor man's autoloading {}
		1517	*condvar = sub {
		1518	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
		1519	};
		1520
		1521	*AE::cv = sub (;&) {
		1522	bless { @_ ? (_ae_cb => shift) : () }, "AnyEvent::CondVar"
		1523	};
		1524	};
		1525	die if $@;
		1526
		1527	&condvar
		1528	}
		1529
		1530	# default implementation for ->signal
		1531
		1532	our $HAVE_ASYNC_INTERRUPT;
		1533
		1534	sub _have_async_interrupt() {
		1535	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
		1536	&& eval "use Async::Interrupt 1.02 (); 1")
		1537	unless defined $HAVE_ASYNC_INTERRUPT;
		1538
		1539	$HAVE_ASYNC_INTERRUPT
		1540	}
		1541
		1542	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1543	our (%SIG_ASY, %SIG_ASY_W);
		1544	our ($SIG_COUNT, $SIG_TW);
		1545
		1546	# install a dummy wakeup watcher to reduce signal catching latency
		1547	# used by Impls
		1548	sub _sig_add() {
		1549	unless ($SIG_COUNT++) {
		1550	# try to align timer on a full-second boundary, if possible
		1551	my $NOW = AE::now;
		1552
		1553	$SIG_TW = AE::timer
		1554	$MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
		1555	$MAX_SIGNAL_LATENCY,
		1556	sub { } # just for the PERL_ASYNC_CHECK
		1557	;
1173	}	1558	}
1174	}	1559	}
1175		1560
1176	sub time { _time }	1561	sub _sig_del {
1177	sub now { _time }	1562	undef $SIG_TW
1178	sub now_update { }	1563	unless --$SIG_COUNT;
1179
1180	# default implementation for ->condvar
1181
1182	sub condvar {
1183	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1184	}	1564	}
1185		1565
1186	# default implementation for ->signal	1566	our $_sig_name_init; $_sig_name_init = sub {
		1567	eval q{ # poor man's autoloading {}
		1568	undef $_sig_name_init;
1187		1569
1188	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1570	if (_have_async_interrupt) {
		1571	*sig2num = \&Async::Interrupt::sig2num;
		1572	*sig2name = \&Async::Interrupt::sig2name;
		1573	} else {
		1574	require Config;
1189		1575
1190	sub _signal_exec {	1576	my %signame2num;
1191	sysread $SIGPIPE_R, my $dummy, 4;	1577	@signame2num{ split ' ', $Config::Config{sig_name} }
		1578	= split ' ', $Config::Config{sig_num};
1192		1579
1193	while (%SIG_EV) {	1580	my @signum2name;
1194	for (keys %SIG_EV) {	1581	@signum2name[values %signame2num] = keys %signame2num;
1195	delete $SIG_EV{$_};	1582
1196	$_->() for values %{ $SIG_CB{$_} || {} };	1583	*sig2num = sub($) {
		1584	$_[0] > 0 ? shift : $signame2num{+shift}
		1585	};
		1586	*sig2name = sub ($) {
		1587	$_[0] > 0 ? $signum2name[+shift] : shift
		1588	};
1197	}	1589	}
1198	}	1590	};
1199	}	1591	die if $@;
		1592	};
		1593
		1594	sub sig2num ($) { &$_sig_name_init; &sig2num }
		1595	sub sig2name($) { &$_sig_name_init; &sig2name }
1200		1596
1201	sub signal {	1597	sub signal {
1202	my (undef, %arg) = @_;	1598	eval q{ # poor man's autoloading {}
		1599	# probe for availability of Async::Interrupt
		1600	if (_have_async_interrupt) {
		1601	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1203		1602
1204	unless ($SIGPIPE_R) {	1603	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1205	require Fcntl;	1604	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1206		1605
1207	if (AnyEvent::WIN32) {
1208	require AnyEvent::Util;
1209
1210	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1211	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1212	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1213	} else {	1606	} else {
		1607	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
		1608
		1609	if (AnyEvent::WIN32) {
		1610	require AnyEvent::Util;
		1611
		1612	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1613	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
		1614	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
		1615	} else {
1214	pipe $SIGPIPE_R, $SIGPIPE_W;	1616	pipe $SIGPIPE_R, $SIGPIPE_W;
1215	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;	1617	fcntl $SIGPIPE_R, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_R;
1216	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case	1618	fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case
1217		1619
1218	# not strictly required, as $^F is normally 2, but let's make sure...	1620	# not strictly required, as $^F is normally 2, but let's make sure...
1219	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1621	fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
1220	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1622	fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
		1623	}
		1624
		1625	$SIGPIPE_R
		1626	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1627
		1628	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
1221	}	1629	}
1222		1630
1223	$SIGPIPE_R	1631	*signal = $HAVE_ASYNC_INTERRUPT
1224	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";	1632	? sub {
		1633	my (undef, %arg) = @_;
1225		1634
1226	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);	1635	# async::interrupt
1227	}
1228
1229	my $signal = uc $arg{signal}	1636	my $signal = sig2num $arg{signal};
1230	or Carp::croak "required option 'signal' is missing";
1231
1232	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1637	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1638
		1639	$SIG_ASY{$signal} ||= new Async::Interrupt
		1640	cb => sub { undef $SIG_EV{$signal} },
		1641	signal => $signal,
		1642	pipe => [$SIGPIPE_R->filenos],
		1643	pipe_autodrain => 0,
		1644	;
		1645
		1646	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1647	}
		1648	: sub {
		1649	my (undef, %arg) = @_;
		1650
		1651	# pure perl
		1652	my $signal = sig2name $arg{signal};
		1653	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1654
1233	$SIG{$signal} ||= sub {	1655	$SIG{$signal} ||= sub {
1234	local $!;	1656	local $!;
1235	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;	1657	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1236	undef $SIG_EV{$signal};	1658	undef $SIG_EV{$signal};
		1659	};
		1660
		1661	# can't do signal processing without introducing races in pure perl,
		1662	# so limit the signal latency.
		1663	_sig_add;
		1664
		1665	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1666	}
		1667	;
		1668
		1669	*AnyEvent::Base::signal::DESTROY = sub {
		1670	my ($signal, $cb) = @{$_[0]};
		1671
		1672	_sig_del;
		1673
		1674	delete $SIG_CB{$signal}{$cb};
		1675
		1676	$HAVE_ASYNC_INTERRUPT
		1677	? delete $SIG_ASY{$signal}
		1678	: # delete doesn't work with older perls - they then
		1679	# print weird messages, or just unconditionally exit
		1680	# instead of getting the default action.
		1681	undef $SIG{$signal}
		1682	unless keys %{ $SIG_CB{$signal} };
		1683	};
		1684
		1685	*_signal_exec = sub {
		1686	$HAVE_ASYNC_INTERRUPT
		1687	? $SIGPIPE_R->drain
		1688	: sysread $SIGPIPE_R, (my $dummy), 9;
		1689
		1690	while (%SIG_EV) {
		1691	for (keys %SIG_EV) {
		1692	delete $SIG_EV{$_};
		1693	&$_ for values %{ $SIG_CB{$_} || {} };
		1694	}
		1695	}
		1696	};
1237	};	1697	};
		1698	die if $@;
1238		1699
1239	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"	1700	&signal
1240	}
1241
1242	sub AnyEvent::Base::signal::DESTROY {
1243	my ($signal, $cb) = @{$_[0]};
1244
1245	delete $SIG_CB{$signal}{$cb};
1246
1247	# delete doesn't work with older perls - they then
1248	# print weird messages, or just unconditionally exit
1249	# instead of getting the default action.
1250	undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
1251	}	1701	}
1252		1702
1253	# default implementation for ->child	1703	# default implementation for ->child
1254		1704
1255	our %PID_CB;	1705	our %PID_CB;
1256	our $CHLD_W;	1706	our $CHLD_W;
1257	our $CHLD_DELAY_W;	1707	our $CHLD_DELAY_W;
1258	our $WNOHANG;
1259		1708
1260	sub _sigchld {	1709	# used by many Impl's
1261	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1710	sub _emit_childstatus($$) {
		1711	my (undef, $rpid, $rstatus) = @_;
		1712
		1713	$_->($rpid, $rstatus)
1262	$_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),	1714	for values %{ $PID_CB{$rpid} || {} },
1263	(values %{ $PID_CB{0} || {} });	1715	values %{ $PID_CB{0} || {} };
1264	}
1265	}	1716	}
1266		1717
1267	sub child {	1718	sub child {
		1719	eval q{ # poor man's autoloading {}
		1720	*_sigchld = sub {
		1721	my $pid;
		1722
		1723	AnyEvent->_emit_childstatus ($pid, $?)
		1724	while ($pid = waitpid -1, WNOHANG) > 0;
		1725	};
		1726
		1727	*child = sub {
1268	my (undef, %arg) = @_;	1728	my (undef, %arg) = @_;
1269		1729
1270	defined (my $pid = $arg{pid} + 0)	1730	my $pid = $arg{pid};
1271	or Carp::croak "required option 'pid' is missing";	1731	my $cb = $arg{cb};
1272		1732
1273	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1733	$PID_CB{$pid}{$cb+0} = $cb;
1274		1734
1275	$WNOHANG ||= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1276
1277	unless ($CHLD_W) {	1735	unless ($CHLD_W) {
1278	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1736	$CHLD_W = AE::signal CHLD => \&_sigchld;
1279	# child could be a zombie already, so make at least one round	1737	# child could be a zombie already, so make at least one round
1280	&_sigchld;	1738	&_sigchld;
1281	}	1739	}
1282		1740
1283	bless [$pid, $arg{cb}], "AnyEvent::Base::child"	1741	bless [$pid, $cb+0], "AnyEvent::Base::child"
1284	}	1742	};
1285		1743
1286	sub AnyEvent::Base::child::DESTROY {	1744	*AnyEvent::Base::child::DESTROY = sub {
1287	my ($pid, $cb) = @{$_[0]};	1745	my ($pid, $icb) = @{$_[0]};
1288		1746
1289	delete $PID_CB{$pid}{$cb};	1747	delete $PID_CB{$pid}{$icb};
1290	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1748	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1291		1749
1292	undef $CHLD_W unless keys %PID_CB;	1750	undef $CHLD_W unless keys %PID_CB;
		1751	};
		1752	};
		1753	die if $@;
		1754
		1755	&child
1293	}	1756	}
1294		1757
1295	# idle emulation is done by simply using a timer, regardless	1758	# idle emulation is done by simply using a timer, regardless
1296	# of whether the process is idle or not, and not letting	1759	# of whether the process is idle or not, and not letting
1297	# the callback use more than 50% of the time.	1760	# the callback use more than 50% of the time.
1298	sub idle {	1761	sub idle {
		1762	eval q{ # poor man's autoloading {}
		1763	*idle = sub {
1299	my (undef, %arg) = @_;	1764	my (undef, %arg) = @_;
1300		1765
1301	my ($cb, $w, $rcb) = $arg{cb};	1766	my ($cb, $w, $rcb) = $arg{cb};
1302		1767
1303	$rcb = sub {	1768	$rcb = sub {
1304	if ($cb) {	1769	if ($cb) {
1305	$w = _time;	1770	$w = AE::time;
1306	&$cb;	1771	&$cb;
1307	$w = _time - $w;	1772	$w = AE::time - $w;
1308		1773
1309	# never use more then 50% of the time for the idle watcher,	1774	# never use more then 50% of the time for the idle watcher,
1310	# within some limits	1775	# within some limits
1311	$w = 0.0001 if $w < 0.0001;	1776	$w = 0.0001 if $w < 0.0001;
1312	$w = 5 if $w > 5;	1777	$w = 5 if $w > 5;
1313		1778
1314	$w = AnyEvent->timer (after => $w, cb => $rcb);	1779	$w = AE::timer $w, 0, $rcb;
1315	} else {	1780	} else {
1316	# clean up...	1781	# clean up...
1317	undef $w;	1782	undef $w;
1318	undef $rcb;	1783	undef $rcb;
		1784	}
		1785	};
		1786
		1787	$w = AE::timer 0.05, 0, $rcb;
		1788
		1789	bless \\$cb, "AnyEvent::Base::idle"
1319	}	1790	};
		1791
		1792	*AnyEvent::Base::idle::DESTROY = sub {
		1793	undef $${$_[0]};
		1794	};
1320	};	1795	};
		1796	die if $@;
1321		1797
1322	$w = AnyEvent->timer (after => 0.05, cb => $rcb);	1798	&idle
1323
1324	bless \\$cb, "AnyEvent::Base::idle"
1325	}
1326
1327	sub AnyEvent::Base::idle::DESTROY {
1328	undef $${$_[0]};
1329	}	1799	}
1330		1800
1331	package AnyEvent::CondVar;	1801	package AnyEvent::CondVar;
1332		1802
1333	our @ISA = AnyEvent::CondVar::Base::;	1803	our @ISA = AnyEvent::CondVar::Base::;
1334		1804
		1805	# only to be used for subclassing
		1806	sub new {
		1807	my $class = shift;
		1808	bless AnyEvent->condvar (@_), $class
		1809	}
		1810
1335	package AnyEvent::CondVar::Base;	1811	package AnyEvent::CondVar::Base;
1336		1812
1337	use overload	1813	#use overload
1338	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1814	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1339	fallback => 1;	1815	# fallback => 1;
		1816
		1817	# save 300+ kilobytes by dirtily hardcoding overloading
		1818	${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
		1819	*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
		1820	*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
		1821	${'AnyEvent::CondVar::Base::()'} = 1; # fallback
		1822
		1823	our $WAITING;
1340		1824
1341	sub _send {	1825	sub _send {
1342	# nop	1826	# nop
		1827	}
		1828
		1829	sub _wait {
		1830	AnyEvent->_poll until $_[0]{_ae_sent};
1343	}	1831	}
1344		1832
1345	sub send {	1833	sub send {
1346	my $cv = shift;	1834	my $cv = shift;
1347	$cv->{_ae_sent} = [@_];	1835	$cv->{_ae_sent} = [@_];
…		…
1356		1844
1357	sub ready {	1845	sub ready {
1358	$_[0]{_ae_sent}	1846	$_[0]{_ae_sent}
1359	}	1847	}
1360		1848
1361	sub _wait {
1362	AnyEvent->one_event while !$_[0]{_ae_sent};
1363	}
1364
1365	sub recv {	1849	sub recv {
		1850	unless ($_[0]{_ae_sent}) {
		1851	$WAITING
		1852	and Carp::croak "AnyEvent::CondVar: recursive blocking wait attempted";
		1853
		1854	local $WAITING = 1;
1366	$_[0]->_wait;	1855	$_[0]->_wait;
		1856	}
1367		1857
1368	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1858	$_[0]{_ae_croak}
1369	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1859	and Carp::croak $_[0]{_ae_croak};
		1860
		1861	wantarray
		1862	? @{ $_[0]{_ae_sent} }
		1863	: $_[0]{_ae_sent}[0]
1370	}	1864	}
1371		1865
1372	sub cb {	1866	sub cb {
1373	$_[0]{_ae_cb} = $_[1] if @_ > 1;	1867	my $cv = shift;
		1868
		1869	@_
		1870	and $cv->{_ae_cb} = shift
		1871	and $cv->{_ae_sent}
		1872	and (delete $cv->{_ae_cb})->($cv);
		1873
1374	$_[0]{_ae_cb}	1874	$cv->{_ae_cb}
1375	}	1875	}
1376		1876
1377	sub begin {	1877	sub begin {
1378	++$_[0]{_ae_counter};	1878	++$_[0]{_ae_counter};
1379	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;	1879	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
…		…
1384	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };	1884	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };
1385	}	1885	}
1386		1886
1387	# undocumented/compatibility with pre-3.4	1887	# undocumented/compatibility with pre-3.4
1388	*broadcast = \&send;	1888	*broadcast = \&send;
1389	*wait = \&_wait;	1889	*wait = \&recv;
1390		1890
1391	=head1 ERROR AND EXCEPTION HANDLING	1891	=head1 ERROR AND EXCEPTION HANDLING
1392		1892
1393	In general, AnyEvent does not do any error handling - it relies on the	1893	In general, AnyEvent does not do any error handling - it relies on the
1394	caller to do that if required. The L<AnyEvent::Strict> module (see also	1894	caller to do that if required. The L<AnyEvent::Strict> module (see also
…		…
1428	C<PERL_ANYEVENT_MODEL>.	1928	C<PERL_ANYEVENT_MODEL>.
1429		1929
1430	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	1930	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1431	model it chooses.	1931	model it chooses.
1432		1932
		1933	When set to C<8> or higher, then AnyEvent will report extra information on
		1934	which optional modules it loads and how it implements certain features.
		1935
1433	=item C<PERL_ANYEVENT_STRICT>	1936	=item C<PERL_ANYEVENT_STRICT>
1434		1937
1435	AnyEvent does not do much argument checking by default, as thorough	1938	AnyEvent does not do much argument checking by default, as thorough
1436	argument checking is very costly. Setting this variable to a true value	1939	argument checking is very costly. Setting this variable to a true value
1437	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly	1940	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1438	check the arguments passed to most method calls. If it finds any problems,	1941	check the arguments passed to most method calls. If it finds any problems,
1439	it will croak.	1942	it will croak.
1440		1943
1441	In other words, enables "strict" mode.	1944	In other words, enables "strict" mode.
1442		1945
1443	Unlike C<use strict>, it is definitely recommended to keep it off in	1946	Unlike C<use strict> (or its modern cousin, C<< use L<common::sense>
1444	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while	1947	>>, it is definitely recommended to keep it off in production. Keeping
1445	developing programs can be very useful, however.	1948	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
		1949	can be very useful, however.
1446		1950
1447	=item C<PERL_ANYEVENT_MODEL>	1951	=item C<PERL_ANYEVENT_MODEL>
1448		1952
1449	This can be used to specify the event model to be used by AnyEvent, before	1953	This can be used to specify the event model to be used by AnyEvent, before
1450	auto detection and -probing kicks in. It must be a string consisting	1954	auto detection and -probing kicks in.
1451	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended	1955
		1956	It normally is a string consisting entirely of ASCII letters (e.g. C<EV>
		1957	or C<IOAsync>). The string C<AnyEvent::Impl::> gets prepended and the
1452	and the resulting module name is loaded and if the load was successful,	1958	resulting module name is loaded and - if the load was successful - used as
1453	used as event model. If it fails to load AnyEvent will proceed with	1959	event model backend. If it fails to load then AnyEvent will proceed with
1454	auto detection and -probing.	1960	auto detection and -probing.
1455		1961
1456	This functionality might change in future versions.	1962	If the string ends with C<::> instead (e.g. C<AnyEvent::Impl::EV::>) then
		1963	nothing gets prepended and the module name is used as-is (hint: C<::> at
		1964	the end of a string designates a module name and quotes it appropriately).
1457		1965
1458	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you	1966	For example, to force the pure perl model (L<AnyEvent::Loop::Perl>) you
1459	could start your program like this:	1967	could start your program like this:
1460		1968
1461	PERL_ANYEVENT_MODEL=Perl perl ...	1969	PERL_ANYEVENT_MODEL=Perl perl ...
1462		1970
1463	=item C<PERL_ANYEVENT_PROTOCOLS>	1971	=item C<PERL_ANYEVENT_PROTOCOLS>
…		…
1512		2020
1513	When neither C<ca_file> nor C<ca_path> was specified during	2021	When neither C<ca_file> nor C<ca_path> was specified during
1514	L<AnyEvent::TLS> context creation, and either of these environment	2022	L<AnyEvent::TLS> context creation, and either of these environment
1515	variables exist, they will be used to specify CA certificate locations	2023	variables exist, they will be used to specify CA certificate locations
1516	instead of a system-dependent default.	2024	instead of a system-dependent default.
		2025
		2026	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
		2027
		2028	When these are set to C<1>, then the respective modules are not
		2029	loaded. Mostly good for testing AnyEvent itself.
1517		2030
1518	=back	2031	=back
1519		2032
1520	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	2033	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1521		2034
…		…
1579	warn "read: $input\n"; # output what has been read	2092	warn "read: $input\n"; # output what has been read
1580	$cv->send if $input =~ /^q/i; # quit program if /^q/i	2093	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1581	},	2094	},
1582	);	2095	);
1583		2096
1584	my $time_watcher; # can only be used once
1585
1586	sub new_timer {
1587	$timer = AnyEvent->timer (after => 1, cb => sub {	2097	my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1588	warn "timeout\n"; # print 'timeout' about every second	2098	warn "timeout\n"; # print 'timeout' at most every second
1589	&new_timer; # and restart the time
1590	});	2099	});
1591	}
1592
1593	new_timer; # create first timer
1594		2100
1595	$cv->recv; # wait until user enters /^q/i	2101	$cv->recv; # wait until user enters /^q/i
1596		2102
1597	=head1 REAL-WORLD EXAMPLE	2103	=head1 REAL-WORLD EXAMPLE
1598		2104
…		…
1671		2177
1672	The actual code goes further and collects all errors (C<die>s, exceptions)	2178	The actual code goes further and collects all errors (C<die>s, exceptions)
1673	that occurred during request processing. The C<result> method detects	2179	that occurred during request processing. The C<result> method detects
1674	whether an exception as thrown (it is stored inside the $txn object)	2180	whether an exception as thrown (it is stored inside the $txn object)
1675	and just throws the exception, which means connection errors and other	2181	and just throws the exception, which means connection errors and other
1676	problems get reported tot he code that tries to use the result, not in a	2182	problems get reported to the code that tries to use the result, not in a
1677	random callback.	2183	random callback.
1678		2184
1679	All of this enables the following usage styles:	2185	All of this enables the following usage styles:
1680		2186
1681	1. Blocking:	2187	1. Blocking:
…		…
1729	through AnyEvent. The benchmark creates a lot of timers (with a zero	2235	through AnyEvent. The benchmark creates a lot of timers (with a zero
1730	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	2236	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1731	which it is), lets them fire exactly once and destroys them again.	2237	which it is), lets them fire exactly once and destroys them again.
1732		2238
1733	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	2239	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1734	distribution.	2240	distribution. It uses the L<AE> interface, which makes a real difference
		2241	for the EV and Perl backends only.
1735		2242
1736	=head3 Explanation of the columns	2243	=head3 Explanation of the columns
1737		2244
1738	I<watcher> is the number of event watchers created/destroyed. Since	2245	I<watcher> is the number of event watchers created/destroyed. Since
1739	different event models feature vastly different performances, each event	2246	different event models feature vastly different performances, each event
…		…
1760	watcher.	2267	watcher.
1761		2268
1762	=head3 Results	2269	=head3 Results
1763		2270
1764	name watchers bytes create invoke destroy comment	2271	name watchers bytes create invoke destroy comment
1765	EV/EV 400000 224 0.47 0.35 0.27 EV native interface	2272	EV/EV 100000 223 0.47 0.43 0.27 EV native interface
1766	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	2273	EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
1767	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal	2274	Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
1768	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation	2275	Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
1769	Event/Event 16000 517 32.20 31.80 0.81 Event native interface	2276	Event/Event 16000 516 31.16 31.84 0.82 Event native interface
1770	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers	2277	Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
1771	IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll	2278	IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
1772	IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll	2279	IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
1773	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour	2280	Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
1774	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers	2281	Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
1775	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event	2282	POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
1776	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select	2283	POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
1777		2284
1778	=head3 Discussion	2285	=head3 Discussion
1779		2286
1780	The benchmark does I<not> measure scalability of the event loop very	2287	The benchmark does I<not> measure scalability of the event loop very
1781	well. For example, a select-based event loop (such as the pure perl one)	2288	well. For example, a select-based event loop (such as the pure perl one)
…		…
1793	benchmark machine, handling an event takes roughly 1600 CPU cycles with	2300	benchmark machine, handling an event takes roughly 1600 CPU cycles with
1794	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU	2301	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
1795	cycles with POE.	2302	cycles with POE.
1796		2303
1797	C<EV> is the sole leader regarding speed and memory use, which are both	2304	C<EV> is the sole leader regarding speed and memory use, which are both
1798	maximal/minimal, respectively. Even when going through AnyEvent, it uses	2305	maximal/minimal, respectively. When using the L<AE> API there is zero
		2306	overhead (when going through the AnyEvent API create is about 5-6 times
		2307	slower, with other times being equal, so still uses far less memory than
1799	far less memory than any other event loop and is still faster than Event	2308	any other event loop and is still faster than Event natively).
1800	natively.
1801		2309
1802	The pure perl implementation is hit in a few sweet spots (both the	2310	The pure perl implementation is hit in a few sweet spots (both the
1803	constant timeout and the use of a single fd hit optimisations in the perl	2311	constant timeout and the use of a single fd hit optimisations in the perl
1804	interpreter and the backend itself). Nevertheless this shows that it	2312	interpreter and the backend itself). Nevertheless this shows that it
1805	adds very little overhead in itself. Like any select-based backend its	2313	adds very little overhead in itself. Like any select-based backend its
…		…
1879	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100	2387	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1880	(1%) are active. This mirrors the activity of large servers with many	2388	(1%) are active. This mirrors the activity of large servers with many
1881	connections, most of which are idle at any one point in time.	2389	connections, most of which are idle at any one point in time.
1882		2390
1883	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	2391	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1884	distribution.	2392	distribution. It uses the L<AE> interface, which makes a real difference
		2393	for the EV and Perl backends only.
1885		2394
1886	=head3 Explanation of the columns	2395	=head3 Explanation of the columns
1887		2396
1888	I<sockets> is the number of sockets, and twice the number of "servers" (as	2397	I<sockets> is the number of sockets, and twice the number of "servers" (as
1889	each server has a read and write socket end).	2398	each server has a read and write socket end).
…		…
1897	a new one that moves the timeout into the future.	2406	a new one that moves the timeout into the future.
1898		2407
1899	=head3 Results	2408	=head3 Results
1900		2409
1901	name sockets create request	2410	name sockets create request
1902	EV 20000 69.01 11.16	2411	EV 20000 62.66 7.99
1903	Perl 20000 73.32 35.87	2412	Perl 20000 68.32 32.64
1904	IOAsync 20000 157.00 98.14 epoll	2413	IOAsync 20000 174.06 101.15 epoll
1905	IOAsync 20000 159.31 616.06 poll	2414	IOAsync 20000 174.67 610.84 poll
1906	Event 20000 212.62 257.32	2415	Event 20000 202.69 242.91
1907	Glib 20000 651.16 1896.30	2416	Glib 20000 557.01 1689.52
1908	POE 20000 349.67 12317.24 uses POE::Loop::Event	2417	POE 20000 341.54 12086.32 uses POE::Loop::Event
1909		2418
1910	=head3 Discussion	2419	=head3 Discussion
1911		2420
1912	This benchmark I<does> measure scalability and overall performance of the	2421	This benchmark I<does> measure scalability and overall performance of the
1913	particular event loop.	2422	particular event loop.
…		…
2039	As you can see, the AnyEvent + EV combination even beats the	2548	As you can see, the AnyEvent + EV combination even beats the
2040	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl	2549	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
2041	backend easily beats IO::Lambda and POE.	2550	backend easily beats IO::Lambda and POE.
2042		2551
2043	And even the 100% non-blocking version written using the high-level (and	2552	And even the 100% non-blocking version written using the high-level (and
2044	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a	2553	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
2045	large margin, even though it does all of DNS, tcp-connect and socket I/O	2554	higher level ("unoptimised") abstractions by a large margin, even though
2046	in a non-blocking way.	2555	it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
2047		2556
2048	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and	2557	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
2049	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are	2558	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
2050	part of the IO::lambda distribution and were used without any changes.	2559	part of the IO::Lambda distribution and were used without any changes.
2051		2560
2052		2561
2053	=head1 SIGNALS	2562	=head1 SIGNALS
2054		2563
2055	AnyEvent currently installs handlers for these signals:	2564	AnyEvent currently installs handlers for these signals:
…		…
2060		2569
2061	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher	2570	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
2062	emulation for event loops that do not support them natively. Also, some	2571	emulation for event loops that do not support them natively. Also, some
2063	event loops install a similar handler.	2572	event loops install a similar handler.
2064		2573
2065	If, when AnyEvent is loaded, SIGCHLD is set to IGNORE, then AnyEvent will	2574	Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
2066	reset it to default, to avoid losing child exit statuses.	2575	AnyEvent will reset it to default, to avoid losing child exit statuses.
2067		2576
2068	=item SIGPIPE	2577	=item SIGPIPE
2069		2578
2070	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>	2579	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
2071	when AnyEvent gets loaded.	2580	when AnyEvent gets loaded.
…		…
2089	if $SIG{CHLD} eq 'IGNORE';	2598	if $SIG{CHLD} eq 'IGNORE';
2090		2599
2091	$SIG{PIPE} = sub { }	2600	$SIG{PIPE} = sub { }
2092	unless defined $SIG{PIPE};	2601	unless defined $SIG{PIPE};
2093		2602
		2603	=head1 RECOMMENDED/OPTIONAL MODULES
		2604
		2605	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
		2606	its built-in modules) are required to use it.
		2607
		2608	That does not mean that AnyEvent won't take advantage of some additional
		2609	modules if they are installed.
		2610
		2611	This section explains which additional modules will be used, and how they
		2612	affect AnyEvent's operation.
		2613
		2614	=over 4
		2615
		2616	=item L<Async::Interrupt>
		2617
		2618	This slightly arcane module is used to implement fast signal handling: To
		2619	my knowledge, there is no way to do completely race-free and quick
		2620	signal handling in pure perl. To ensure that signals still get
		2621	delivered, AnyEvent will start an interval timer to wake up perl (and
		2622	catch the signals) with some delay (default is 10 seconds, look for
		2623	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
		2624
		2625	If this module is available, then it will be used to implement signal
		2626	catching, which means that signals will not be delayed, and the event loop
		2627	will not be interrupted regularly, which is more efficient (and good for
		2628	battery life on laptops).
		2629
		2630	This affects not just the pure-perl event loop, but also other event loops
		2631	that have no signal handling on their own (e.g. Glib, Tk, Qt).
		2632
		2633	Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
		2634	and either employ their own workarounds (POE) or use AnyEvent's workaround
		2635	(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
		2636	does nothing for those backends.
		2637
		2638	=item L<EV>
		2639
		2640	This module isn't really "optional", as it is simply one of the backend
		2641	event loops that AnyEvent can use. However, it is simply the best event
		2642	loop available in terms of features, speed and stability: It supports
		2643	the AnyEvent API optimally, implements all the watcher types in XS, does
		2644	automatic timer adjustments even when no monotonic clock is available,
		2645	can take avdantage of advanced kernel interfaces such as C<epoll> and
		2646	C<kqueue>, and is the fastest backend I<by far>. You can even embed
		2647	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
		2648
		2649	If you only use backends that rely on another event loop (e.g. C<Tk>),
		2650	then this module will do nothing for you.
		2651
		2652	=item L<Guard>
		2653
		2654	The guard module, when used, will be used to implement
		2655	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
		2656	lot less memory), but otherwise doesn't affect guard operation much. It is
		2657	purely used for performance.
		2658
		2659	=item L<JSON> and L<JSON::XS>
		2660
		2661	One of these modules is required when you want to read or write JSON data
		2662	via L<AnyEvent::Handle>. L<JSON> is also written in pure-perl, but can take
		2663	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
		2664
		2665	=item L<Net::SSLeay>
		2666
		2667	Implementing TLS/SSL in Perl is certainly interesting, but not very
		2668	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
		2669	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
		2670
		2671	=item L<Time::HiRes>
		2672
		2673	This module is part of perl since release 5.008. It will be used when the
		2674	chosen event library does not come with a timing source of its own. The
		2675	pure-perl event loop (L<AnyEvent::Loop>) will additionally load it to
		2676	try to use a monotonic clock for timing stability.
		2677
		2678	=back
		2679
		2680
2094	=head1 FORK	2681	=head1 FORK
2095		2682
2096	Most event libraries are not fork-safe. The ones who are usually are	2683	Most event libraries are not fork-safe. The ones who are usually are
2097	because they rely on inefficient but fork-safe C<select> or C<poll>	2684	because they rely on inefficient but fork-safe C<select> or C<poll> calls
2098	calls. Only L<EV> is fully fork-aware.	2685	- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
		2686	are usually badly thought-out hacks that are incompatible with fork in
		2687	one way or another. Only L<EV> is fully fork-aware and ensures that you
		2688	continue event-processing in both parent and child (or both, if you know
		2689	what you are doing).
		2690
		2691	This means that, in general, you cannot fork and do event processing in
		2692	the child if the event library was initialised before the fork (which
		2693	usually happens when the first AnyEvent watcher is created, or the library
		2694	is loaded).
2099		2695
2100	If you have to fork, you must either do so I<before> creating your first	2696	If you have to fork, you must either do so I<before> creating your first
2101	watcher OR you must not use AnyEvent at all in the child.	2697	watcher OR you must not use AnyEvent at all in the child OR you must do
		2698	something completely out of the scope of AnyEvent.
		2699
		2700	The problem of doing event processing in the parent I<and> the child
		2701	is much more complicated: even for backends that I<are> fork-aware or
		2702	fork-safe, their behaviour is not usually what you want: fork clones all
		2703	watchers, that means all timers, I/O watchers etc. are active in both
		2704	parent and child, which is almost never what you want. USing C<exec>
		2705	to start worker children from some kind of manage rprocess is usually
		2706	preferred, because it is much easier and cleaner, at the expense of having
		2707	to have another binary.
2102		2708
2103		2709
2104	=head1 SECURITY CONSIDERATIONS	2710	=head1 SECURITY CONSIDERATIONS
2105		2711
2106	AnyEvent can be forced to load any event model via	2712	AnyEvent can be forced to load any event model via
…		…
2136	pronounced).	2742	pronounced).
2137		2743
2138		2744
2139	=head1 SEE ALSO	2745	=head1 SEE ALSO
2140		2746
		2747	Tutorial/Introduction: L<AnyEvent::Intro>.
		2748
		2749	FAQ: L<AnyEvent::FAQ>.
		2750
2141	Utility functions: L<AnyEvent::Util>.	2751	Utility functions: L<AnyEvent::Util>.
2142		2752
2143	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,	2753	Event modules: L<AnyEvent::Loop>, L<EV>, L<EV::Glib>, L<Glib::EV>,
2144	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2754	L<Event>, L<Glib::Event>, L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
2145		2755
2146	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2756	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
2147	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2757	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
2148	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2758	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
2149	L<AnyEvent::Impl::POE>.	2759	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.
2150		2760
2151	Non-blocking file handles, sockets, TCP clients and	2761	Non-blocking file handles, sockets, TCP clients and
2152	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.	2762	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2153		2763
2154	Asynchronous DNS: L<AnyEvent::DNS>.	2764	Asynchronous DNS: L<AnyEvent::DNS>.
2155		2765
2156	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,	2766	Thread support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>.
2157		2767
2158	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.	2768	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::IRC>,
		2769	L<AnyEvent::HTTP>.
2159		2770
2160		2771
2161	=head1 AUTHOR	2772	=head1 AUTHOR
2162		2773
2163	Marc Lehmann <schmorp@schmorp.de>	2774	Marc Lehmann <schmorp@schmorp.de>

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