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Revision 1.338 by root, Tue Nov 23 04:45:59 2010 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 + IO::Async? No go. Tk + Event? No go. Again: if
78	your module uses one of those, every user of your module has to use it,	91	your module uses one of those, every user of your module has to use it,
79	too. But if your module uses AnyEvent, it works transparently with all	92	too. But if your module uses AnyEvent, it works transparently with all
80	event models it supports (including stuff like IO::Async, as long as those	93	event models it supports (including stuff like IO::Async, as long as those
81	use one of the supported event loops. It is trivial to add new event loops	94	use one of the supported event loops. It is easy to add new event loops
82	to AnyEvent, too, so it is future-proof).	95	to AnyEvent, too, 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::Impl::Perl>,
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::Impl::Perl> 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
136	C<AnyEvent::Impl::Perl>. Like other event modules you can load it	148	C<AnyEvent::Impl::Perl>. Like other event modules you can load it
137	explicitly and enjoy the high availability of that event loop :)	149	explicitly and enjoy the high availability of that event loop :)
138		150
…		…
147	callback when the event occurs (of course, only when the event model	159	callback when the event occurs (of course, only when the event model
148	is in control).	160	is in control).
149		161
150	Note that B<callbacks must not permanently change global variables>	162	Note that B<callbacks must not permanently change global variables>
151	potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<	163	potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<
152	callbacks must not C<die> >>. The former is good programming practise in	164	callbacks must not C<die> >>. The former is good programming practice in
153	Perl and the latter stems from the fact that exception handling differs	165	Perl and the latter stems from the fact that exception handling differs
154	widely between event loops.	166	widely between event loops.
155		167
156	To disable the watcher you have to destroy it (e.g. by setting the	168	To disable a watcher you have to destroy it (e.g. by setting the
157	variable you store it in to C<undef> or otherwise deleting all references	169	variable you store it in to C<undef> or otherwise deleting all references
158	to it).	170	to it).
159		171
160	All watchers are created by calling a method on the C<AnyEvent> class.	172	All watchers are created by calling a method on the C<AnyEvent> class.
161		173
162	Many watchers either are used with "recursion" (repeating timers for	174	Many watchers either are used with "recursion" (repeating timers for
163	example), or need to refer to their watcher object in other ways.	175	example), or need to refer to their watcher object in other ways.
164		176
165	An any way to achieve that is this pattern:	177	One way to achieve that is this pattern:
166		178
167	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {	179	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
168	# you can use $w here, for example to undef it	180	# you can use $w here, for example to undef it
169	undef $w;	181	undef $w;
170	});	182	});
…		…
172	Note that C<my $w; $w => combination. This is necessary because in Perl,	184	Note that C<my $w; $w => combination. This is necessary because in Perl,
173	my variables are only visible after the statement in which they are	185	my variables are only visible after the statement in which they are
174	declared.	186	declared.
175		187
176	=head2 I/O WATCHERS	188	=head2 I/O WATCHERS
		189
		190	$w = AnyEvent->io (
		191	fh => <filehandle_or_fileno>,
		192	poll => <"r" or "w">,
		193	cb => <callback>,
		194	);
177		195
178	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	196	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
179	with the following mandatory key-value pairs as arguments:	197	with the following mandatory key-value pairs as arguments:
180		198
181	C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch	199	C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch
…		…
196		214
197	The I/O watcher might use the underlying file descriptor or a copy of it.	215	The I/O watcher might use the underlying file descriptor or a copy of it.
198	You must not close a file handle as long as any watcher is active on the	216	You must not close a file handle as long as any watcher is active on the
199	underlying file descriptor.	217	underlying file descriptor.
200		218
201	Some event loops issue spurious readyness notifications, so you should	219	Some event loops issue spurious readiness notifications, so you should
202	always use non-blocking calls when reading/writing from/to your file	220	always use non-blocking calls when reading/writing from/to your file
203	handles.	221	handles.
204		222
205	Example: wait for readability of STDIN, then read a line and disable the	223	Example: wait for readability of STDIN, then read a line and disable the
206	watcher.	224	watcher.
…		…
211	undef $w;	229	undef $w;
212	});	230	});
213		231
214	=head2 TIME WATCHERS	232	=head2 TIME WATCHERS
215		233
		234	$w = AnyEvent->timer (after => <seconds>, cb => <callback>);
		235
		236	$w = AnyEvent->timer (
		237	after => <fractional_seconds>,
		238	interval => <fractional_seconds>,
		239	cb => <callback>,
		240	);
		241
216	You can create a time watcher by calling the C<< AnyEvent->timer >>	242	You can create a time watcher by calling the C<< AnyEvent->timer >>
217	method with the following mandatory arguments:	243	method with the following mandatory arguments:
218		244
219	C<after> specifies after how many seconds (fractional values are	245	C<after> specifies after how many seconds (fractional values are
220	supported) the callback should be invoked. C<cb> is the callback to invoke	246	supported) the callback should be invoked. C<cb> is the callback to invoke
…		…
222		248
223	Although the callback might get passed parameters, their value and	249	Although the callback might get passed parameters, their value and
224	presence is undefined and you cannot rely on them. Portable AnyEvent	250	presence is undefined and you cannot rely on them. Portable AnyEvent
225	callbacks cannot use arguments passed to time watcher callbacks.	251	callbacks cannot use arguments passed to time watcher callbacks.
226		252
227	The callback will normally be invoked once only. If you specify another	253	The callback will normally be invoked only once. If you specify another
228	parameter, C<interval>, as a strictly positive number (> 0), then the	254	parameter, C<interval>, as a strictly positive number (> 0), then the
229	callback will be invoked regularly at that interval (in fractional	255	callback will be invoked regularly at that interval (in fractional
230	seconds) after the first invocation. If C<interval> is specified with a	256	seconds) after the first invocation. If C<interval> is specified with a
231	false value, then it is treated as if it were missing.	257	false value, then it is treated as if it were not specified at all.
232		258
233	The callback will be rescheduled before invoking the callback, but no	259	The callback will be rescheduled before invoking the callback, but no
234	attempt is done to avoid timer drift in most backends, so the interval is	260	attempt is made to avoid timer drift in most backends, so the interval is
235	only approximate.	261	only approximate.
236		262
237	Example: fire an event after 7.7 seconds.	263	Example: fire an event after 7.7 seconds.
238		264
239	my $w = AnyEvent->timer (after => 7.7, cb => sub {	265	my $w = AnyEvent->timer (after => 7.7, cb => sub {
…		…
257		283
258	While most event loops expect timers to specified in a relative way, they	284	While most event loops expect timers to specified in a relative way, they
259	use absolute time internally. This makes a difference when your clock	285	use absolute time internally. This makes a difference when your clock
260	"jumps", for example, when ntp decides to set your clock backwards from	286	"jumps", for example, when ntp decides to set your clock backwards from
261	the wrong date of 2014-01-01 to 2008-01-01, a watcher that is supposed to	287	the wrong date of 2014-01-01 to 2008-01-01, a watcher that is supposed to
262	fire "after" a second might actually take six years to finally fire.	288	fire "after a second" might actually take six years to finally fire.
263		289
264	AnyEvent cannot compensate for this. The only event loop that is conscious	290	AnyEvent cannot compensate for this. The only event loop that is conscious
265	about these issues is L<EV>, which offers both relative (ev_timer, based	291	of these issues is L<EV>, which offers both relative (ev_timer, based
266	on true relative time) and absolute (ev_periodic, based on wallclock time)	292	on true relative time) and absolute (ev_periodic, based on wallclock time)
267	timers.	293	timers.
268		294
269	AnyEvent always prefers relative timers, if available, matching the	295	AnyEvent always prefers relative timers, if available, matching the
270	AnyEvent API.	296	AnyEvent API.
…		…
292	I<In almost all cases (in all cases if you don't care), this is the	318	I<In almost all cases (in all cases if you don't care), this is the
293	function to call when you want to know the current time.>	319	function to call when you want to know the current time.>
294		320
295	This function is also often faster then C<< AnyEvent->time >>, and	321	This function is also often faster then C<< AnyEvent->time >>, and
296	thus the preferred method if you want some timestamp (for example,	322	thus the preferred method if you want some timestamp (for example,
297	L<AnyEvent::Handle> uses this to update it's activity timeouts).	323	L<AnyEvent::Handle> uses this to update its activity timeouts).
298		324
299	The rest of this section is only of relevance if you try to be very exact	325	The rest of this section is only of relevance if you try to be very exact
300	with your timing, you can skip it without bad conscience.	326	with your timing; you can skip it without a bad conscience.
301		327
302	For a practical example of when these times differ, consider L<Event::Lib>	328	For a practical example of when these times differ, consider L<Event::Lib>
303	and L<EV> and the following set-up:	329	and L<EV> and the following set-up:
304		330
305	The event loop is running and has just invoked one of your callback at	331	The event loop is running and has just invoked one of your callbacks at
306	time=500 (assume no other callbacks delay processing). In your callback,	332	time=500 (assume no other callbacks delay processing). In your callback,
307	you wait a second by executing C<sleep 1> (blocking the process for a	333	you wait a second by executing C<sleep 1> (blocking the process for a
308	second) and then (at time=501) you create a relative timer that fires	334	second) and then (at time=501) you create a relative timer that fires
309	after three seconds.	335	after three seconds.
310		336
…		…
341	might affect timers and time-outs.	367	might affect timers and time-outs.
342		368
343	When this is the case, you can call this method, which will update the	369	When this is the case, you can call this method, which will update the
344	event loop's idea of "current time".	370	event loop's idea of "current time".
345		371
		372	A typical example would be a script in a web server (e.g. C<mod_perl>) -
		373	when mod_perl executes the script, then the event loop will have the wrong
		374	idea about the "current time" (being potentially far in the past, when the
		375	script ran the last time). In that case you should arrange a call to C<<
		376	AnyEvent->now_update >> each time the web server process wakes up again
		377	(e.g. at the start of your script, or in a handler).
		378
346	Note that updating the time I<might> cause some events to be handled.	379	Note that updating the time I<might> cause some events to be handled.
347		380
348	=back	381	=back
349		382
350	=head2 SIGNAL WATCHERS	383	=head2 SIGNAL WATCHERS
		384
		385	$w = AnyEvent->signal (signal => <uppercase_signal_name>, cb => <callback>);
351		386
352	You can watch for signals using a signal watcher, C<signal> is the signal	387	You can watch for signals using a signal watcher, C<signal> is the signal
353	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl	388	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
354	callback to be invoked whenever a signal occurs.	389	callback to be invoked whenever a signal occurs.
355		390
…		…
361	invocation, and callback invocation will be synchronous. Synchronous means	396	invocation, and callback invocation will be synchronous. Synchronous means
362	that it might take a while until the signal gets handled by the process,	397	that it might take a while until the signal gets handled by the process,
363	but it is guaranteed not to interrupt any other callbacks.	398	but it is guaranteed not to interrupt any other callbacks.
364		399
365	The main advantage of using these watchers is that you can share a signal	400	The main advantage of using these watchers is that you can share a signal
366	between multiple watchers.	401	between multiple watchers, and AnyEvent will ensure that signals will not
		402	interrupt your program at bad times.
367		403
368	This watcher might use C<%SIG>, so programs overwriting those signals	404	This watcher might use C<%SIG> (depending on the event loop used),
369	directly will likely not work correctly.	405	so programs overwriting those signals directly will likely not work
		406	correctly.
370		407
371	Example: exit on SIGINT	408	Example: exit on SIGINT
372		409
373	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });	410	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
374		411
		412	=head3 Restart Behaviour
		413
		414	While restart behaviour is up to the event loop implementation, most will
		415	not restart syscalls (that includes L<Async::Interrupt> and AnyEvent's
		416	pure perl implementation).
		417
		418	=head3 Safe/Unsafe Signals
		419
		420	Perl signals can be either "safe" (synchronous to opcode handling) or
		421	"unsafe" (asynchronous) - the former might get delayed indefinitely, the
		422	latter might corrupt your memory.
		423
		424	AnyEvent signal handlers are, in addition, synchronous to the event loop,
		425	i.e. they will not interrupt your running perl program but will only be
		426	called as part of the normal event handling (just like timer, I/O etc.
		427	callbacks, too).
		428
		429	=head3 Signal Races, Delays and Workarounds
		430
		431	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
		432	callbacks to signals in a generic way, which is a pity, as you cannot
		433	do race-free signal handling in perl, requiring C libraries for
		434	this. AnyEvent will try to do its best, which means in some cases,
		435	signals will be delayed. The maximum time a signal might be delayed is
		436	specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This
		437	variable can be changed only before the first signal watcher is created,
		438	and should be left alone otherwise. This variable determines how often
		439	AnyEvent polls for signals (in case a wake-up was missed). Higher values
		440	will cause fewer spurious wake-ups, which is better for power and CPU
		441	saving.
		442
		443	All these problems can be avoided by installing the optional
		444	L<Async::Interrupt> module, which works with most event loops. It will not
		445	work with inherently broken event loops such as L<Event> or L<Event::Lib>
		446	(and not with L<POE> currently, as POE does its own workaround with
		447	one-second latency). For those, you just have to suffer the delays.
		448
375	=head2 CHILD PROCESS WATCHERS	449	=head2 CHILD PROCESS WATCHERS
376		450
		451	$w = AnyEvent->child (pid => <process id>, cb => <callback>);
		452
377	You can also watch on a child process exit and catch its exit status.	453	You can also watch for a child process exit and catch its exit status.
378		454
379	The child process is specified by the C<pid> argument (if set to C<0>, it	455	The child process is specified by the C<pid> argument (on some backends,
380	watches for any child process exit). The watcher will triggered only when	456	using C<0> watches for any child process exit, on others this will
381	the child process has finished and an exit status is available, not on	457	croak). The watcher will be triggered only when the child process has
382	any trace events (stopped/continued).	458	finished and an exit status is available, not on any trace events
		459	(stopped/continued).
383		460
384	The callback will be called with the pid and exit status (as returned by	461	The callback will be called with the pid and exit status (as returned by
385	waitpid), so unlike other watcher types, you I<can> rely on child watcher	462	waitpid), so unlike other watcher types, you I<can> rely on child watcher
386	callback arguments.	463	callback arguments.
387		464
…		…
403		480
404	This means you cannot create a child watcher as the very first	481	This means you cannot create a child watcher as the very first
405	thing in an AnyEvent program, you I<have> to create at least one	482	thing in an AnyEvent program, you I<have> to create at least one
406	watcher before you C<fork> the child (alternatively, you can call	483	watcher before you C<fork> the child (alternatively, you can call
407	C<AnyEvent::detect>).	484	C<AnyEvent::detect>).
		485
		486	As most event loops do not support waiting for child events, they will be
		487	emulated by AnyEvent in most cases, in which the latency and race problems
		488	mentioned in the description of signal watchers apply.
408		489
409	Example: fork a process and wait for it	490	Example: fork a process and wait for it
410		491
411	my $done = AnyEvent->condvar;	492	my $done = AnyEvent->condvar;
412		493
…		…
424	# do something else, then wait for process exit	505	# do something else, then wait for process exit
425	$done->recv;	506	$done->recv;
426		507
427	=head2 IDLE WATCHERS	508	=head2 IDLE WATCHERS
428		509
429	Sometimes there is a need to do something, but it is not so important	510	$w = AnyEvent->idle (cb => <callback>);
430	to do it instantly, but only when there is nothing better to do. This
431	"nothing better to do" is usually defined to be "no other events need
432	attention by the event loop".
433		511
434	Idle watchers ideally get invoked when the event loop has nothing	512	This will repeatedly invoke the callback after the process becomes idle,
435	better to do, just before it would block the process to wait for new	513	until either the watcher is destroyed or new events have been detected.
436	events. Instead of blocking, the idle watcher is invoked.
437		514
438	Most event loops unfortunately do not really support idle watchers (only	515	Idle watchers are useful when there is a need to do something, but it
		516	is not so important (or wise) to do it instantly. The callback will be
		517	invoked only when there is "nothing better to do", which is usually
		518	defined as "all outstanding events have been handled and no new events
		519	have been detected". That means that idle watchers ideally get invoked
		520	when the event loop has just polled for new events but none have been
		521	detected. Instead of blocking to wait for more events, the idle watchers
		522	will be invoked.
		523
		524	Unfortunately, most event loops do not really support idle watchers (only
439	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent	525	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
440	will simply call the callback "from time to time".	526	will simply call the callback "from time to time".
441		527
442	Example: read lines from STDIN, but only process them when the	528	Example: read lines from STDIN, but only process them when the
443	program is otherwise idle:	529	program is otherwise idle:
…		…
459	});	545	});
460	});	546	});
461		547
462	=head2 CONDITION VARIABLES	548	=head2 CONDITION VARIABLES
463		549
		550	$cv = AnyEvent->condvar;
		551
		552	$cv->send (<list>);
		553	my @res = $cv->recv;
		554
464	If you are familiar with some event loops you will know that all of them	555	If you are familiar with some event loops you will know that all of them
465	require you to run some blocking "loop", "run" or similar function that	556	require you to run some blocking "loop", "run" or similar function that
466	will actively watch for new events and call your callbacks.	557	will actively watch for new events and call your callbacks.
467		558
468	AnyEvent is slightly different: it expects somebody else to run the event	559	AnyEvent is slightly different: it expects somebody else to run the event
469	loop and will only block when necessary (usually when told by the user).	560	loop and will only block when necessary (usually when told by the user).
470		561
471	The instrument to do that is called a "condition variable", so called	562	The tool to do that is called a "condition variable", so called because
472	because they represent a condition that must become true.	563	they represent a condition that must become true.
473		564
474	Now is probably a good time to look at the examples further below.	565	Now is probably a good time to look at the examples further below.
475		566
476	Condition variables can be created by calling the C<< AnyEvent->condvar	567	Condition variables can be created by calling the C<< AnyEvent->condvar
477	>> method, usually without arguments. The only argument pair allowed is	568	>> method, usually without arguments. The only argument pair allowed is
…		…
482	After creation, the condition variable is "false" until it becomes "true"	573	After creation, the condition variable is "false" until it becomes "true"
483	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
484	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<<
485	->send >> method).	576	->send >> method).
486		577
487	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
488	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:
489	in time where multiple outstanding events have been processed. And yet	580
490	another way to call them is transactions - each condition variable can be	581	=over 4
491	used to represent a transaction, which finishes at some point and delivers	582
492	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
493		601
494	Condition variables are very useful to signal that something has finished,	602	Condition variables are very useful to signal that something has finished,
495	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,
496	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
497	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
…		…
510		618
511	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
512	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
513	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
514	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
515	it's C<new> method in your own C<new> method.	623	its C<new> method in your own C<new> method.
516		624
517	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
518	eventually calls C<< -> send >>, and the "consumer side", which waits	626	eventually calls C<< -> send >>, and the "consumer side", which waits
519	for the send to occur.	627	for the send to occur.
520		628
521	Example: wait for a timer.	629	Example: wait for a timer.
522		630
523	# wait till the result is ready	631	# condition: "wait till the timer is fired"
524	my $result_ready = AnyEvent->condvar;	632	my $timer_fired = AnyEvent->condvar;
525		633
526	# do something such as adding a timer	634	# create the timer - we could wait for, say
527	# or socket watcher the calls $result_ready->send	635	# a handle becomign ready, or even an
528	# when the "result" is ready.	636	# AnyEvent::HTTP request to finish, but
529	# in this case, we simply use a timer:	637	# in this case, we simply use a timer:
530	my $w = AnyEvent->timer (	638	my $w = AnyEvent->timer (
531	after => 1,	639	after => 1,
532	cb => sub { $result_ready->send },	640	cb => sub { $timer_fired->send },
533	);	641	);
534		642
535	# this "blocks" (while handling events) till the callback	643	# this "blocks" (while handling events) till the callback
536	# calls -<send	644	# calls ->send
537	$result_ready->recv;	645	$timer_fired->recv;
538		646
539	Example: wait for a timer, but take advantage of the fact that condition	647	Example: wait for a timer, but take advantage of the fact that condition
540	variables are also callable directly.	648	variables are also callable directly.
541		649
542	my $done = AnyEvent->condvar;	650	my $done = AnyEvent->condvar;
…		…
585	they were a code reference). Calling them directly is the same as calling	693	they were a code reference). Calling them directly is the same as calling
586	C<send>.	694	C<send>.
587		695
588	=item $cv->croak ($error)	696	=item $cv->croak ($error)
589		697
590	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
591	C<Carp::croak> with the given error message/object/scalar.	699	C<Carp::croak> with the given error message/object/scalar.
592		700
593	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
594	user/consumer. Doing it this way instead of calling C<croak> directly	702	user/consumer. Doing it this way instead of calling C<croak> directly
595	delays the error detetcion, but has the overwhelmign advantage that it	703	delays the error detection, but has the overwhelming advantage that it
596	diagnoses the error at the place where the result is expected, and not	704	diagnoses the error at the place where the result is expected, and not
597	deep in some event clalback without connection to the actual code causing	705	deep in some event callback with no connection to the actual code causing
598	the problem.	706	the problem.
599		707
600	=item $cv->begin ([group callback])	708	=item $cv->begin ([group callback])
601		709
602	=item $cv->end	710	=item $cv->end
…		…
605	one. For example, a function that pings many hosts in parallel might want	713	one. For example, a function that pings many hosts in parallel might want
606	to use a condition variable for the whole process.	714	to use a condition variable for the whole process.
607		715
608	Every call to C<< ->begin >> will increment a counter, and every call to	716	Every call to C<< ->begin >> will increment a counter, and every call to
609	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end	717	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
610	>>, the (last) callback passed to C<begin> will be executed. That callback	718	>>, the (last) callback passed to C<begin> will be executed, passing the
611	is I<supposed> to call C<< ->send >>, but that is not required. If no	719	condvar as first argument. That callback is I<supposed> to call C<< ->send
612	callback was set, C<send> will be called without any arguments.	720	>>, but that is not required. If no group callback was set, C<send> will
		721	be called without any arguments.
613		722
614	You can think of C<< $cv->send >> giving you an OR condition (one call	723	You can think of C<< $cv->send >> giving you an OR condition (one call
615	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND	724	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
616	condition (all C<begin> calls must be C<end>'ed before the condvar sends).	725	condition (all C<begin> calls must be C<end>'ed before the condvar sends).
617		726
…		…
639	one call to C<begin>, so the condvar waits for all calls to C<end> before	748	one call to C<begin>, so the condvar waits for all calls to C<end> before
640	sending.	749	sending.
641		750
642	The ping example mentioned above is slightly more complicated, as the	751	The ping example mentioned above is slightly more complicated, as the
643	there are results to be passwd back, and the number of tasks that are	752	there are results to be passwd back, and the number of tasks that are
644	begung can potentially be zero:	753	begun can potentially be zero:
645		754
646	my $cv = AnyEvent->condvar;	755	my $cv = AnyEvent->condvar;
647		756
648	my %result;	757	my %result;
649	$cv->begin (sub { $cv->send (\%result) });	758	$cv->begin (sub { shift->send (\%result) });
650		759
651	for my $host (@list_of_hosts) {	760	for my $host (@list_of_hosts) {
652	$cv->begin;	761	$cv->begin;
653	ping_host_then_call_callback $host, sub {	762	ping_host_then_call_callback $host, sub {
654	$result{$host} = ...;	763	$result{$host} = ...;
…		…
670	to be called once the counter reaches C<0>, and second, it ensures that	779	to be called once the counter reaches C<0>, and second, it ensures that
671	C<send> is called even when C<no> hosts are being pinged (the loop	780	C<send> is called even when C<no> hosts are being pinged (the loop
672	doesn't execute once).	781	doesn't execute once).
673		782
674	This is the general pattern when you "fan out" into multiple (but	783	This is the general pattern when you "fan out" into multiple (but
675	potentially none) subrequests: use an outer C<begin>/C<end> pair to set	784	potentially zero) subrequests: use an outer C<begin>/C<end> pair to set
676	the callback and ensure C<end> is called at least once, and then, for each	785	the callback and ensure C<end> is called at least once, and then, for each
677	subrequest you start, call C<begin> and for each subrequest you finish,	786	subrequest you start, call C<begin> and for each subrequest you finish,
678	call C<end>.	787	call C<end>.
679		788
680	=back	789	=back
…		…
687	=over 4	796	=over 4
688		797
689	=item $cv->recv	798	=item $cv->recv
690		799
691	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak	800	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
692	>> methods have been called on c<$cv>, while servicing other watchers	801	>> methods have been called on C<$cv>, while servicing other watchers
693	normally.	802	normally.
694		803
695	You can only wait once on a condition - additional calls are valid but	804	You can only wait once on a condition - additional calls are valid but
696	will return immediately.	805	will return immediately.
697		806
…		…
714	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
715	condition variables with some kind of request results and supporting	824	condition variables with some kind of request results and supporting
716	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,
717	while still supporting blocking waits if the caller so desires).	826	while still supporting blocking waits if the caller so desires).
718		827
719	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
720	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
721	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
722	waits otherwise.	831	waits otherwise.
723		832
724	=item $bool = $cv->ready	833	=item $bool = $cv->ready
…		…
730		839
731	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
732	replaces it before doing so.	841	replaces it before doing so.
733		842
734	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
735	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
736	variable itself. Calling C<recv> inside the callback or at any later time	845	condition variable itself. If the condition is already true, the
737	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.
738		848
739	=back	849	=back
740		850
741	=head1 SUPPORTED EVENT LOOPS/BACKENDS	851	=head1 SUPPORTED EVENT LOOPS/BACKENDS
742		852
…		…
745	=over 4	855	=over 4
746		856
747	=item Backends that are autoprobed when no other event loop can be found.	857	=item Backends that are autoprobed when no other event loop can be found.
748		858
749	EV is the preferred backend when no other event loop seems to be in	859	EV is the preferred backend when no other event loop seems to be in
750	use. If EV is not installed, then AnyEvent will try Event, and, failing	860	use. If EV is not installed, then AnyEvent will fall back to its own
751	that, will fall back to its own pure-perl implementation, which is	861	pure-perl implementation, which is available everywhere as it comes with
752	available everywhere as it comes with AnyEvent itself.	862	AnyEvent itself.
753		863
754	AnyEvent::Impl::EV based on EV (interface to libev, best choice).	864	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
755	AnyEvent::Impl::Event based on Event, very stable, few glitches.
756	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.	865	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
757		866
758	=item Backends that are transparently being picked up when they are used.	867	=item Backends that are transparently being picked up when they are used.
759		868
760	These will be used when they are currently loaded when the first watcher	869	These will be used if they are already loaded when the first watcher
761	is created, in which case it is assumed that the application is using	870	is created, in which case it is assumed that the application is using
762	them. This means that AnyEvent will automatically pick the right backend	871	them. This means that AnyEvent will automatically pick the right backend
763	when the main program loads an event module before anything starts to	872	when the main program loads an event module before anything starts to
764	create watchers. Nothing special needs to be done by the main program.	873	create watchers. Nothing special needs to be done by the main program.
765		874
		875	AnyEvent::Impl::Event based on Event, very stable, few glitches.
766	AnyEvent::Impl::Glib based on Glib, slow but very stable.	876	AnyEvent::Impl::Glib based on Glib, slow but very stable.
767	AnyEvent::Impl::Tk based on Tk, very broken.	877	AnyEvent::Impl::Tk based on Tk, very broken.
768	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.	878	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
769	AnyEvent::Impl::POE based on POE, very slow, some limitations.	879	AnyEvent::Impl::POE based on POE, very slow, some limitations.
		880	AnyEvent::Impl::Irssi used when running within irssi.
770		881
771	=item Backends with special needs.	882	=item Backends with special needs.
772		883
773	Qt requires the Qt::Application to be instantiated first, but will	884	Qt requires the Qt::Application to be instantiated first, but will
774	otherwise be picked up automatically. As long as the main program	885	otherwise be picked up automatically. As long as the main program
…		…
779		890
780	Support for IO::Async can only be partial, as it is too broken and	891	Support for IO::Async can only be partial, as it is too broken and
781	architecturally limited to even support the AnyEvent API. It also	892	architecturally limited to even support the AnyEvent API. It also
782	is the only event loop that needs the loop to be set explicitly, so	893	is the only event loop that needs the loop to be set explicitly, so
783	it can only be used by a main program knowing about AnyEvent. See	894	it can only be used by a main program knowing about AnyEvent. See
784	L<AnyEvent::Impl::Async> for the gory details.	895	L<AnyEvent::Impl::IOAsync> for the gory details.
785		896
786	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.	897	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
787		898
788	=item Event loops that are indirectly supported via other backends.	899	=item Event loops that are indirectly supported via other backends.
789		900
…		…
817	Contains C<undef> until the first watcher is being created, before the	928	Contains C<undef> until the first watcher is being created, before the
818	backend has been autodetected.	929	backend has been autodetected.
819		930
820	Afterwards it contains the event model that is being used, which is the	931	Afterwards it contains the event model that is being used, which is the
821	name of the Perl class implementing the model. This class is usually one	932	name of the Perl class implementing the model. This class is usually one
822	of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the	933	of the C<AnyEvent::Impl::xxx> modules, but can be any other class in the
823	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it	934	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
824	will be C<urxvt::anyevent>).	935	will be C<urxvt::anyevent>).
825		936
826	=item AnyEvent::detect	937	=item AnyEvent::detect
827		938
828	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	939	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
829	if necessary. You should only call this function right before you would	940	if necessary. You should only call this function right before you would
830	have created an AnyEvent watcher anyway, that is, as late as possible at	941	have created an AnyEvent watcher anyway, that is, as late as possible at
831	runtime, and not e.g. while initialising of your module.	942	runtime, and not e.g. during initialisation of your module.
832		943
833	If you need to do some initialisation before AnyEvent watchers are	944	If you need to do some initialisation before AnyEvent watchers are
834	created, use C<post_detect>.	945	created, use C<post_detect>.
835		946
836	=item $guard = AnyEvent::post_detect { BLOCK }	947	=item $guard = AnyEvent::post_detect { BLOCK }
837		948
838	Arranges for the code block to be executed as soon as the event model is	949	Arranges for the code block to be executed as soon as the event model is
839	autodetected (or immediately if this has already happened).	950	autodetected (or immediately if that has already happened).
840		951
841	The block will be executed I<after> the actual backend has been detected	952	The block will be executed I<after> the actual backend has been detected
842	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been	953	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
843	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do	954	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
844	other initialisations - see the sources of L<AnyEvent::Strict> or	955	other initialisations - see the sources of L<AnyEvent::Strict> or
…		…
848	event module detection too early, for example, L<AnyEvent::AIO> creates	959	event module detection too early, for example, L<AnyEvent::AIO> creates
849	and installs the global L<IO::AIO> watcher in a C<post_detect> block to	960	and installs the global L<IO::AIO> watcher in a C<post_detect> block to
850	avoid autodetecting the event module at load time.	961	avoid autodetecting the event module at load time.
851		962
852	If called in scalar or list context, then it creates and returns an object	963	If called in scalar or list context, then it creates and returns an object
853	that automatically removes the callback again when it is destroyed. See	964	that automatically removes the callback again when it is destroyed (or
		965	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
854	L<Coro::BDB> for a case where this is useful.	966	a case where this is useful.
		967
		968	Example: Create a watcher for the IO::AIO module and store it in
		969	C<$WATCHER>, but do so only do so after the event loop is initialised.
		970
		971	our WATCHER;
		972
		973	my $guard = AnyEvent::post_detect {
		974	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
		975	};
		976
		977	# the ||= is important in case post_detect immediately runs the block,
		978	# as to not clobber the newly-created watcher. assigning both watcher and
		979	# post_detect guard to the same variable has the advantage of users being
		980	# able to just C<undef $WATCHER> if the watcher causes them grief.
		981
		982	$WATCHER ||= $guard;
855		983
856	=item @AnyEvent::post_detect	984	=item @AnyEvent::post_detect
857		985
858	If there are any code references in this array (you can C<push> to it	986	If there are any code references in this array (you can C<push> to it
859	before or after loading AnyEvent), then they will called directly after	987	before or after loading AnyEvent), then they will be called directly
860	the event loop has been chosen.	988	after the event loop has been chosen.
861		989
862	You should check C<$AnyEvent::MODEL> before adding to this array, though:	990	You should check C<$AnyEvent::MODEL> before adding to this array, though:
863	if it is defined then the event loop has already been detected, and the	991	if it is defined then the event loop has already been detected, and the
864	array will be ignored.	992	array will be ignored.
865		993
866	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows	994	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
867	it,as it takes care of these details.	995	it, as it takes care of these details.
868		996
869	This variable is mainly useful for modules that can do something useful	997	This variable is mainly useful for modules that can do something useful
870	when AnyEvent is used and thus want to know when it is initialised, but do	998	when AnyEvent is used and thus want to know when it is initialised, but do
871	not need to even load it by default. This array provides the means to hook	999	not need to even load it by default. This array provides the means to hook
872	into AnyEvent passively, without loading it.	1000	into AnyEvent passively, without loading it.
873		1001
		1002	Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used
		1003	together, you could put this into Coro (this is the actual code used by
		1004	Coro to accomplish this):
		1005
		1006	if (defined $AnyEvent::MODEL) {
		1007	# AnyEvent already initialised, so load Coro::AnyEvent
		1008	require Coro::AnyEvent;
		1009	} else {
		1010	# AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
		1011	# as soon as it is
		1012	push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
		1013	}
		1014
874	=back	1015	=back
875		1016
876	=head1 WHAT TO DO IN A MODULE	1017	=head1 WHAT TO DO IN A MODULE
877		1018
878	As a module author, you should C<use AnyEvent> and call AnyEvent methods	1019	As a module author, you should C<use AnyEvent> and call AnyEvent methods
…		…
888	because it will stall the whole program, and the whole point of using	1029	because it will stall the whole program, and the whole point of using
889	events is to stay interactive.	1030	events is to stay interactive.
890		1031
891	It is fine, however, to call C<< ->recv >> when the user of your module	1032	It is fine, however, to call C<< ->recv >> when the user of your module
892	requests it (i.e. if you create a http request object ad have a method	1033	requests it (i.e. if you create a http request object ad have a method
893	called C<results> that returns the results, it should call C<< ->recv >>	1034	called C<results> that returns the results, it may call C<< ->recv >>
894	freely, as the user of your module knows what she is doing. always).	1035	freely, as the user of your module knows what she is doing. Always).
895		1036
896	=head1 WHAT TO DO IN THE MAIN PROGRAM	1037	=head1 WHAT TO DO IN THE MAIN PROGRAM
897		1038
898	There will always be a single main program - the only place that should	1039	There will always be a single main program - the only place that should
899	dictate which event model to use.	1040	dictate which event model to use.
900		1041
901	If it doesn't care, it can just "use AnyEvent" and use it itself, or not	1042	If the program is not event-based, it need not do anything special, even
902	do anything special (it does not need to be event-based) and let AnyEvent	1043	when it depends on a module that uses an AnyEvent. If the program itself
903	decide which implementation to chose if some module relies on it.	1044	uses AnyEvent, but does not care which event loop is used, all it needs
		1045	to do is C<use AnyEvent>. In either case, AnyEvent will choose the best
		1046	available loop implementation.
904		1047
905	If the main program relies on a specific event model - for example, in	1048	If the main program relies on a specific event model - for example, in
906	Gtk2 programs you have to rely on the Glib module - you should load the	1049	Gtk2 programs you have to rely on the Glib module - you should load the
907	event module before loading AnyEvent or any module that uses it: generally	1050	event module before loading AnyEvent or any module that uses it: generally
908	speaking, you should load it as early as possible. The reason is that	1051	speaking, you should load it as early as possible. The reason is that
909	modules might create watchers when they are loaded, and AnyEvent will	1052	modules might create watchers when they are loaded, and AnyEvent will
910	decide on the event model to use as soon as it creates watchers, and it	1053	decide on the event model to use as soon as it creates watchers, and it
911	might chose the wrong one unless you load the correct one yourself.	1054	might choose the wrong one unless you load the correct one yourself.
912		1055
913	You can chose to use a pure-perl implementation by loading the	1056	You can chose to use a pure-perl implementation by loading the
914	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour	1057	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour
915	everywhere, but letting AnyEvent chose the model is generally better.	1058	everywhere, but letting AnyEvent chose the model is generally better.
916		1059
…		…
934	=head1 OTHER MODULES	1077	=head1 OTHER MODULES
935		1078
936	The following is a non-exhaustive list of additional modules that use	1079	The following is a non-exhaustive list of additional modules that use
937	AnyEvent as a client and can therefore be mixed easily with other AnyEvent	1080	AnyEvent as a client and can therefore be mixed easily with other AnyEvent
938	modules and other event loops in the same program. Some of the modules	1081	modules and other event loops in the same program. Some of the modules
939	come with AnyEvent, most are available via CPAN.	1082	come as part of AnyEvent, the others are available via CPAN.
940		1083
941	=over 4	1084	=over 4
942		1085
943	=item L<AnyEvent::Util>	1086	=item L<AnyEvent::Util>
944		1087
945	Contains various utility functions that replace often-used but blocking	1088	Contains various utility functions that replace often-used blocking
946	functions such as C<inet_aton> by event-/callback-based versions.	1089	functions such as C<inet_aton> with event/callback-based versions.
947		1090
948	=item L<AnyEvent::Socket>	1091	=item L<AnyEvent::Socket>
949		1092
950	Provides various utility functions for (internet protocol) sockets,	1093	Provides various utility functions for (internet protocol) sockets,
951	addresses and name resolution. Also functions to create non-blocking tcp	1094	addresses and name resolution. Also functions to create non-blocking tcp
…		…
953		1096
954	=item L<AnyEvent::Handle>	1097	=item L<AnyEvent::Handle>
955		1098
956	Provide read and write buffers, manages watchers for reads and writes,	1099	Provide read and write buffers, manages watchers for reads and writes,
957	supports raw and formatted I/O, I/O queued and fully transparent and	1100	supports raw and formatted I/O, I/O queued and fully transparent and
958	non-blocking SSL/TLS (via L<AnyEvent::TLS>.	1101	non-blocking SSL/TLS (via L<AnyEvent::TLS>).
959		1102
960	=item L<AnyEvent::DNS>	1103	=item L<AnyEvent::DNS>
961		1104
962	Provides rich asynchronous DNS resolver capabilities.	1105	Provides rich asynchronous DNS resolver capabilities.
963		1106
		1107	=item L<AnyEvent::HTTP>, L<AnyEvent::IRC>, L<AnyEvent::XMPP>, L<AnyEvent::GPSD>, L<AnyEvent::IGS>, L<AnyEvent::FCP>
		1108
		1109	Implement event-based interfaces to the protocols of the same name (for
		1110	the curious, IGS is the International Go Server and FCP is the Freenet
		1111	Client Protocol).
		1112
		1113	=item L<AnyEvent::Handle::UDP>
		1114
		1115	Here be danger!
		1116
		1117	As Pauli would put it, "Not only is it not right, it's not even wrong!" -
		1118	there are so many things wrong with AnyEvent::Handle::UDP, most notably
		1119	its use of a stream-based API with a protocol that isn't streamable, that
		1120	the only way to improve it is to delete it.
		1121
		1122	It features data corruption (but typically only under load) and general
		1123	confusion. On top, the author is not only clueless about UDP but also
		1124	fact-resistant - some gems of his understanding: "connect doesn't work
		1125	with UDP", "UDP packets are not IP packets", "UDP only has datagrams, not
		1126	packets", "I don't need to implement proper error checking as UDP doesn't
		1127	support error checking" and so on - he doesn't even understand what's
		1128	wrong with his module when it is explained to him.
		1129
964	=item L<AnyEvent::HTTP>	1130	=item L<AnyEvent::DBI>
965		1131
966	A simple-to-use HTTP library that is capable of making a lot of concurrent	1132	Executes L<DBI> requests asynchronously in a proxy process for you,
967	HTTP requests.	1133	notifying you in an event-based way when the operation is finished.
		1134
		1135	=item L<AnyEvent::AIO>
		1136
		1137	Truly asynchronous (as opposed to non-blocking) I/O, should be in the
		1138	toolbox of every event programmer. AnyEvent::AIO transparently fuses
		1139	L<IO::AIO> and AnyEvent together, giving AnyEvent access to event-based
		1140	file I/O, and much more.
968		1141
969	=item L<AnyEvent::HTTPD>	1142	=item L<AnyEvent::HTTPD>
970		1143
971	Provides a simple web application server framework.	1144	A simple embedded webserver.
972		1145
973	=item L<AnyEvent::FastPing>	1146	=item L<AnyEvent::FastPing>
974		1147
975	The fastest ping in the west.	1148	The fastest ping in the west.
976		1149
977	=item L<AnyEvent::DBI>
978
979	Executes L<DBI> requests asynchronously in a proxy process.
980
981	=item L<AnyEvent::AIO>
982
983	Truly asynchronous I/O, should be in the toolbox of every event
984	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
985	together.
986
987	=item L<AnyEvent::BDB>
988
989	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
990	L<BDB> and AnyEvent together.
991
992	=item L<AnyEvent::GPSD>
993
994	A non-blocking interface to gpsd, a daemon delivering GPS information.
995
996	=item L<AnyEvent::IRC>
997
998	AnyEvent based IRC client module family (replacing the older Net::IRC3).
999
1000	=item L<AnyEvent::XMPP>
1001
1002	AnyEvent based XMPP (Jabber protocol) module family (replacing the older
1003	Net::XMPP2>.
1004
1005	=item L<AnyEvent::IGS>
1006
1007	A non-blocking interface to the Internet Go Server protocol (used by
1008	L<App::IGS>).
1009
1010	=item L<Net::FCP>
1011
1012	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
1013	of AnyEvent.
1014
1015	=item L<Event::ExecFlow>
1016
1017	High level API for event-based execution flow control.
1018
1019	=item L<Coro>	1150	=item L<Coro>
1020		1151
1021	Has special support for AnyEvent via L<Coro::AnyEvent>.	1152	Has special support for AnyEvent via L<Coro::AnyEvent>.
1022		1153
1023	=back	1154	=back
1024		1155
1025	=cut	1156	=cut
1026		1157
1027	package AnyEvent;	1158	package AnyEvent;
1028		1159
1029	no warnings;	1160	# basically a tuned-down version of common::sense
1030	use strict qw(vars subs);	1161	sub common_sense {
		1162	# from common:.sense 3.3
		1163	${^WARNING_BITS} ^= ${^WARNING_BITS} ^ "\x3c\x3f\x33\x00\x0f\xf3\x0f\xc0\xf0\xfc\x33\x00";
		1164	# use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)
		1165	$^H |= 0x00000600;
		1166	}
		1167
		1168	BEGIN { AnyEvent::common_sense }
1031		1169
1032	use Carp ();	1170	use Carp ();
1033		1171
1034	our $VERSION = 4.82;	1172	our $VERSION = '5.29';
1035	our $MODEL;	1173	our $MODEL;
1036		1174
1037	our $AUTOLOAD;	1175	our $AUTOLOAD;
1038	our @ISA;	1176	our @ISA;
1039		1177
1040	our @REGISTRY;	1178	our @REGISTRY;
1041		1179
1042	our $WIN32;	1180	our $VERBOSE;
1043		1181
1044	BEGIN {	1182	BEGIN {
1045	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";	1183	require "AnyEvent/constants.pl";
		1184
1046	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";	1185	eval "sub TAINT (){" . (${^TAINT}*1) . "}";
1047		1186
1048	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}	1187	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
1049	if ${^TAINT};	1188	if ${^TAINT};
1050	}
1051		1189
1052	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1190	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
		1191
		1192	}
		1193
		1194	our $MAX_SIGNAL_LATENCY = 10;
1053		1195
1054	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred	1196	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
1055		1197
1056	{	1198	{
1057	my $idx;	1199	my $idx;
…		…
1059	for reverse split /\s*,\s*/,	1201	for reverse split /\s*,\s*/,
1060	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1202	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
1061	}	1203	}
1062		1204
1063	my @models = (	1205	my @models = (
1064	[EV:: => AnyEvent::Impl::EV::],	1206	[EV:: => AnyEvent::Impl::EV:: , 1],
1065	[Event:: => AnyEvent::Impl::Event::],
1066	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	1207	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],
1067	# everything below here will not be autoprobed	1208	# everything below here will not (normally) be autoprobed
1068	# as the pureperl backend should work everywhere	1209	# as the pureperl backend should work everywhere
1069	# and is usually faster	1210	# and is usually faster
		1211	[Event:: => AnyEvent::Impl::Event::, 1],
1070	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers	1212	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
1071	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	1213	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
		1214	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
1072	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1215	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
1073	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1216	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
1074	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1217	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
1075	[Wx:: => AnyEvent::Impl::POE::],	1218	[Wx:: => AnyEvent::Impl::POE::],
1076	[Prima:: => AnyEvent::Impl::POE::],	1219	[Prima:: => AnyEvent::Impl::POE::],
1077	# IO::Async is just too broken - we would need workarounds for its	1220	# IO::Async is just too broken - we would need workarounds for its
1078	# byzantine signal and broken child handling, among others.	1221	# byzantine signal and broken child handling, among others.
1079	# IO::Async is rather hard to detect, as it doesn't have any	1222	# IO::Async is rather hard to detect, as it doesn't have any
1080	# obvious default class.	1223	# obvious default class.
1081	# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program	1224	[IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
1082	# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program	1225	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
1083	# [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program	1226	[IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1227	[AnyEvent::Impl::IOAsync:: => AnyEvent::Impl::IOAsync::], # requires special main program
1084	);	1228	);
1085		1229
1086	our %method = map +($_ => 1),	1230	our %method = map +($_ => 1),
1087	qw(io timer time now now_update signal child idle condvar one_event DESTROY);	1231	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
1088		1232
1089	our @post_detect;	1233	our @post_detect;
1090		1234
1091	sub post_detect(&) {	1235	sub post_detect(&) {
1092	my ($cb) = @_;	1236	my ($cb) = @_;
1093		1237
1094	if ($MODEL) {
1095	$cb->();
1096
1097	1
1098	} else {
1099	push @post_detect, $cb;	1238	push @post_detect, $cb;
1100		1239
1101	defined wantarray	1240	defined wantarray
1102	? bless \$cb, "AnyEvent::Util::postdetect"	1241	? bless \$cb, "AnyEvent::Util::postdetect"
1103	: ()	1242	: ()
1104	}
1105	}	1243	}
1106		1244
1107	sub AnyEvent::Util::postdetect::DESTROY {	1245	sub AnyEvent::Util::postdetect::DESTROY {
1108	@post_detect = grep $_ != ${$_[0]}, @post_detect;	1246	@post_detect = grep $_ != ${$_[0]}, @post_detect;
1109	}	1247	}
1110		1248
1111	sub detect() {	1249	sub detect() {
		1250	# free some memory
		1251	*detect = sub () { $MODEL };
		1252
		1253	local $!; # for good measure
		1254	local $SIG{__DIE__};
		1255
		1256	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
		1257	my $model = "AnyEvent::Impl::$1";
		1258	if (eval "require $model") {
		1259	$MODEL = $model;
		1260	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
		1261	} else {
		1262	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
		1263	}
		1264	}
		1265
		1266	# check for already loaded models
1112	unless ($MODEL) {	1267	unless ($MODEL) {
1113	no strict 'refs';	1268	for (@REGISTRY, @models) {
1114	local $SIG{__DIE__};	1269	my ($package, $model) = @$_;
1115		1270	if (${"$package\::VERSION"} > 0) {
1116	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
1117	my $model = "AnyEvent::Impl::$1";
1118	if (eval "require $model") {	1271	if (eval "require $model") {
1119	$MODEL = $model;	1272	$MODEL = $model;
1120	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $verbose > 1;	1273	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1121	} else {	1274	last;
1122	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $verbose;	1275	}
1123	}	1276	}
1124	}	1277	}
1125		1278
1126	# check for already loaded models
1127	unless ($MODEL) {	1279	unless ($MODEL) {
		1280	# try to autoload a model
1128	for (@REGISTRY, @models) {	1281	for (@REGISTRY, @models) {
1129	my ($package, $model) = @$_;	1282	my ($package, $model, $autoload) = @$_;
		1283	if (
		1284	$autoload
		1285	and eval "require $package"
1130	if (${"$package\::VERSION"} > 0) {	1286	and ${"$package\::VERSION"} > 0
1131	if (eval "require $model") {	1287	and eval "require $model"
		1288	) {
1132	$MODEL = $model;	1289	$MODEL = $model;
1133	warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1;	1290	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
1134	last;	1291	last;
1135	}
1136	}	1292	}
1137	}	1293	}
1138		1294
1139	unless ($MODEL) {
1140	# try to load a model
1141
1142	for (@REGISTRY, @models) {
1143	my ($package, $model) = @$_;
1144	if (eval "require $package"
1145	and ${"$package\::VERSION"} > 0
1146	and eval "require $model") {
1147	$MODEL = $model;
1148	warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1;
1149	last;
1150	}
1151	}
1152
1153	$MODEL	1295	$MODEL
1154	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";	1296	or die "AnyEvent: backend autodetection failed - did you properly install AnyEvent?\n";
1155	}
1156	}	1297	}
1157
1158	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1159
1160	unshift @ISA, $MODEL;
1161
1162	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
1163
1164	(shift @post_detect)->() while @post_detect;
1165	}	1298	}
		1299
		1300	@models = (); # free probe data
		1301
		1302	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1303	unshift @ISA, $MODEL;
		1304
		1305	# now nuke some methods that are overridden by the backend.
		1306	# SUPER is not allowed.
		1307	for (qw(time signal child idle)) {
		1308	undef &{"AnyEvent::Base::$_"}
		1309	if defined &{"$MODEL\::$_"};
		1310	}
		1311
		1312	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
		1313
		1314	(shift @post_detect)->() while @post_detect;
		1315
		1316	*post_detect = sub(&) {
		1317	shift->();
		1318
		1319	undef
		1320	};
1166		1321
1167	$MODEL	1322	$MODEL
1168	}	1323	}
1169		1324
1170	sub AUTOLOAD {	1325	sub AUTOLOAD {
1171	(my $func = $AUTOLOAD) =~ s/.*://;	1326	(my $func = $AUTOLOAD) =~ s/.*://;
1172		1327
1173	$method{$func}	1328	$method{$func}
1174	or Carp::croak "$func: not a valid method for AnyEvent objects";	1329	or Carp::croak "$func: not a valid AnyEvent class method";
1175		1330
1176	detect unless $MODEL;	1331	detect;
1177		1332
1178	my $class = shift;	1333	my $class = shift;
1179	$class->$func (@_);	1334	$class->$func (@_);
1180	}	1335	}
1181		1336
…		…
1184	# allow only one watcher per fd, so we dup it to get a different one).	1339	# allow only one watcher per fd, so we dup it to get a different one).
1185	sub _dupfh($$;$$) {	1340	sub _dupfh($$;$$) {
1186	my ($poll, $fh, $r, $w) = @_;	1341	my ($poll, $fh, $r, $w) = @_;
1187		1342
1188	# cygwin requires the fh mode to be matching, unix doesn't	1343	# cygwin requires the fh mode to be matching, unix doesn't
1189	my ($rw, $mode) = $poll eq "r" ? ($r, "<") : ($w, ">");	1344	my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1190		1345
1191	open my $fh2, "$mode&", $fh	1346	open my $fh2, $mode, $fh
1192	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";	1347	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1193		1348
1194	# we assume CLOEXEC is already set by perl in all important cases	1349	# we assume CLOEXEC is already set by perl in all important cases
1195		1350
1196	($fh2, $rw)	1351	($fh2, $rw)
1197	}	1352	}
1198		1353
		1354	=head1 SIMPLIFIED AE API
		1355
		1356	Starting with version 5.0, AnyEvent officially supports a second, much
		1357	simpler, API that is designed to reduce the calling, typing and memory
		1358	overhead by using function call syntax and a fixed number of parameters.
		1359
		1360	See the L<AE> manpage for details.
		1361
		1362	=cut
		1363
		1364	package AE;
		1365
		1366	our $VERSION = $AnyEvent::VERSION;
		1367
		1368	# fall back to the main API by default - backends and AnyEvent::Base
		1369	# implementations can overwrite these.
		1370
		1371	sub io($$$) {
		1372	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
		1373	}
		1374
		1375	sub timer($$$) {
		1376	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
		1377	}
		1378
		1379	sub signal($$) {
		1380	AnyEvent->signal (signal => $_[0], cb => $_[1])
		1381	}
		1382
		1383	sub child($$) {
		1384	AnyEvent->child (pid => $_[0], cb => $_[1])
		1385	}
		1386
		1387	sub idle($) {
		1388	AnyEvent->idle (cb => $_[0])
		1389	}
		1390
		1391	sub cv(;&) {
		1392	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
		1393	}
		1394
		1395	sub now() {
		1396	AnyEvent->now
		1397	}
		1398
		1399	sub now_update() {
		1400	AnyEvent->now_update
		1401	}
		1402
		1403	sub time() {
		1404	AnyEvent->time
		1405	}
		1406
1199	package AnyEvent::Base;	1407	package AnyEvent::Base;
1200		1408
1201	# default implementations for many methods	1409	# default implementations for many methods
1202		1410
1203	BEGIN {	1411	sub time {
		1412	eval q{ # poor man's autoloading {}
		1413	# probe for availability of Time::HiRes
1204	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {	1414	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1415	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1205	*_time = \&Time::HiRes::time;	1416	*AE::time = \&Time::HiRes::time;
1206	# if (eval "use POSIX (); (POSIX::times())...	1417	# if (eval "use POSIX (); (POSIX::times())...
1207	} else {	1418	} else {
		1419	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1208	*_time = sub { time }; # epic fail	1420	*AE::time = sub (){ time }; # epic fail
		1421	}
		1422
		1423	*time = sub { AE::time }; # different prototypes
		1424	};
		1425	die if $@;
		1426
		1427	&time
		1428	}
		1429
		1430	*now = \&time;
		1431
		1432	sub now_update { }
		1433
		1434	# default implementation for ->condvar
		1435
		1436	sub condvar {
		1437	eval q{ # poor man's autoloading {}
		1438	*condvar = sub {
		1439	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
		1440	};
		1441
		1442	*AE::cv = sub (;&) {
		1443	bless { @_ ? (_ae_cb => shift) : () }, "AnyEvent::CondVar"
		1444	};
		1445	};
		1446	die if $@;
		1447
		1448	&condvar
		1449	}
		1450
		1451	# default implementation for ->signal
		1452
		1453	our $HAVE_ASYNC_INTERRUPT;
		1454
		1455	sub _have_async_interrupt() {
		1456	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
		1457	&& eval "use Async::Interrupt 1.02 (); 1")
		1458	unless defined $HAVE_ASYNC_INTERRUPT;
		1459
		1460	$HAVE_ASYNC_INTERRUPT
		1461	}
		1462
		1463	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1464	our (%SIG_ASY, %SIG_ASY_W);
		1465	our ($SIG_COUNT, $SIG_TW);
		1466
		1467	# install a dummy wakeup watcher to reduce signal catching latency
		1468	# used by Impls
		1469	sub _sig_add() {
		1470	unless ($SIG_COUNT++) {
		1471	# try to align timer on a full-second boundary, if possible
		1472	my $NOW = AE::now;
		1473
		1474	$SIG_TW = AE::timer
		1475	$MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
		1476	$MAX_SIGNAL_LATENCY,
		1477	sub { } # just for the PERL_ASYNC_CHECK
		1478	;
1209	}	1479	}
1210	}	1480	}
1211		1481
1212	sub time { _time }	1482	sub _sig_del {
1213	sub now { _time }	1483	undef $SIG_TW
1214	sub now_update { }	1484	unless --$SIG_COUNT;
1215
1216	# default implementation for ->condvar
1217
1218	sub condvar {
1219	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1220	}	1485	}
1221		1486
1222	# default implementation for ->signal	1487	our $_sig_name_init; $_sig_name_init = sub {
		1488	eval q{ # poor man's autoloading {}
		1489	undef $_sig_name_init;
1223		1490
1224	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1491	if (_have_async_interrupt) {
		1492	*sig2num = \&Async::Interrupt::sig2num;
		1493	*sig2name = \&Async::Interrupt::sig2name;
		1494	} else {
		1495	require Config;
1225		1496
1226	sub _signal_exec {	1497	my %signame2num;
1227	sysread $SIGPIPE_R, my $dummy, 4;	1498	@signame2num{ split ' ', $Config::Config{sig_name} }
		1499	= split ' ', $Config::Config{sig_num};
1228		1500
1229	while (%SIG_EV) {	1501	my @signum2name;
1230	for (keys %SIG_EV) {	1502	@signum2name[values %signame2num] = keys %signame2num;
1231	delete $SIG_EV{$_};	1503
1232	$_->() for values %{ $SIG_CB{$_} || {} };	1504	*sig2num = sub($) {
		1505	$_[0] > 0 ? shift : $signame2num{+shift}
		1506	};
		1507	*sig2name = sub ($) {
		1508	$_[0] > 0 ? $signum2name[+shift] : shift
		1509	};
1233	}	1510	}
1234	}	1511	};
1235	}	1512	die if $@;
		1513	};
		1514
		1515	sub sig2num ($) { &$_sig_name_init; &sig2num }
		1516	sub sig2name($) { &$_sig_name_init; &sig2name }
1236		1517
1237	sub signal {	1518	sub signal {
1238	my (undef, %arg) = @_;	1519	eval q{ # poor man's autoloading {}
		1520	# probe for availability of Async::Interrupt
		1521	if (_have_async_interrupt) {
		1522	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1239		1523
1240	unless ($SIGPIPE_R) {	1524	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1241	require Fcntl;	1525	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1242		1526
1243	if (AnyEvent::WIN32) {
1244	require AnyEvent::Util;
1245
1246	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1247	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1248	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1249	} else {	1527	} else {
		1528	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
		1529
		1530	if (AnyEvent::WIN32) {
		1531	require AnyEvent::Util;
		1532
		1533	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1534	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
		1535	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
		1536	} else {
1250	pipe $SIGPIPE_R, $SIGPIPE_W;	1537	pipe $SIGPIPE_R, $SIGPIPE_W;
1251	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;	1538	fcntl $SIGPIPE_R, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_R;
1252	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case	1539	fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case
1253		1540
1254	# not strictly required, as $^F is normally 2, but let's make sure...	1541	# not strictly required, as $^F is normally 2, but let's make sure...
1255	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1542	fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
1256	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1543	fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
		1544	}
		1545
		1546	$SIGPIPE_R
		1547	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1548
		1549	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
1257	}	1550	}
1258		1551
1259	$SIGPIPE_R	1552	*signal = $HAVE_ASYNC_INTERRUPT
1260	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";	1553	? sub {
		1554	my (undef, %arg) = @_;
1261		1555
1262	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);	1556	# async::interrupt
1263	}
1264
1265	my $signal = uc $arg{signal}	1557	my $signal = sig2num $arg{signal};
1266	or Carp::croak "required option 'signal' is missing";
1267
1268	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1558	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1559
		1560	$SIG_ASY{$signal} ||= new Async::Interrupt
		1561	cb => sub { undef $SIG_EV{$signal} },
		1562	signal => $signal,
		1563	pipe => [$SIGPIPE_R->filenos],
		1564	pipe_autodrain => 0,
		1565	;
		1566
		1567	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1568	}
		1569	: sub {
		1570	my (undef, %arg) = @_;
		1571
		1572	# pure perl
		1573	my $signal = sig2name $arg{signal};
		1574	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1575
1269	$SIG{$signal} ||= sub {	1576	$SIG{$signal} ||= sub {
1270	local $!;	1577	local $!;
1271	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;	1578	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1272	undef $SIG_EV{$signal};	1579	undef $SIG_EV{$signal};
		1580	};
		1581
		1582	# can't do signal processing without introducing races in pure perl,
		1583	# so limit the signal latency.
		1584	_sig_add;
		1585
		1586	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1587	}
		1588	;
		1589
		1590	*AnyEvent::Base::signal::DESTROY = sub {
		1591	my ($signal, $cb) = @{$_[0]};
		1592
		1593	_sig_del;
		1594
		1595	delete $SIG_CB{$signal}{$cb};
		1596
		1597	$HAVE_ASYNC_INTERRUPT
		1598	? delete $SIG_ASY{$signal}
		1599	: # delete doesn't work with older perls - they then
		1600	# print weird messages, or just unconditionally exit
		1601	# instead of getting the default action.
		1602	undef $SIG{$signal}
		1603	unless keys %{ $SIG_CB{$signal} };
		1604	};
		1605
		1606	*_signal_exec = sub {
		1607	$HAVE_ASYNC_INTERRUPT
		1608	? $SIGPIPE_R->drain
		1609	: sysread $SIGPIPE_R, (my $dummy), 9;
		1610
		1611	while (%SIG_EV) {
		1612	for (keys %SIG_EV) {
		1613	delete $SIG_EV{$_};
		1614	$_->() for values %{ $SIG_CB{$_} || {} };
		1615	}
		1616	}
		1617	};
1273	};	1618	};
		1619	die if $@;
1274		1620
1275	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"	1621	&signal
1276	}
1277
1278	sub AnyEvent::Base::signal::DESTROY {
1279	my ($signal, $cb) = @{$_[0]};
1280
1281	delete $SIG_CB{$signal}{$cb};
1282
1283	# delete doesn't work with older perls - they then
1284	# print weird messages, or just unconditionally exit
1285	# instead of getting the default action.
1286	undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
1287	}	1622	}
1288		1623
1289	# default implementation for ->child	1624	# default implementation for ->child
1290		1625
1291	our %PID_CB;	1626	our %PID_CB;
1292	our $CHLD_W;	1627	our $CHLD_W;
1293	our $CHLD_DELAY_W;	1628	our $CHLD_DELAY_W;
1294	our $WNOHANG;	1629	our $WNOHANG;
1295		1630
1296	sub _sigchld {	1631	# used by many Impl's
1297	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1632	sub _emit_childstatus($$) {
		1633	my (undef, $rpid, $rstatus) = @_;
		1634
		1635	$_->($rpid, $rstatus)
1298	$_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),	1636	for values %{ $PID_CB{$rpid} || {} },
1299	(values %{ $PID_CB{0} || {} });	1637	values %{ $PID_CB{0} || {} };
1300	}
1301	}	1638	}
1302		1639
1303	sub child {	1640	sub child {
		1641	eval q{ # poor man's autoloading {}
		1642	*_sigchld = sub {
		1643	my $pid;
		1644
		1645	AnyEvent->_emit_childstatus ($pid, $?)
		1646	while ($pid = waitpid -1, $WNOHANG) > 0;
		1647	};
		1648
		1649	*child = sub {
1304	my (undef, %arg) = @_;	1650	my (undef, %arg) = @_;
1305		1651
1306	defined (my $pid = $arg{pid} + 0)	1652	defined (my $pid = $arg{pid} + 0)
1307	or Carp::croak "required option 'pid' is missing";	1653	or Carp::croak "required option 'pid' is missing";
1308		1654
1309	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1655	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1310		1656
		1657	# WNOHANG is almost cetrainly 1 everywhere
		1658	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
		1659	? 1
1311	$WNOHANG ||= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;	1660	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1312		1661
1313	unless ($CHLD_W) {	1662	unless ($CHLD_W) {
1314	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1663	$CHLD_W = AE::signal CHLD => \&_sigchld;
1315	# child could be a zombie already, so make at least one round	1664	# child could be a zombie already, so make at least one round
1316	&_sigchld;	1665	&_sigchld;
1317	}	1666	}
1318		1667
1319	bless [$pid, $arg{cb}], "AnyEvent::Base::child"	1668	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1320	}	1669	};
1321		1670
1322	sub AnyEvent::Base::child::DESTROY {	1671	*AnyEvent::Base::child::DESTROY = sub {
1323	my ($pid, $cb) = @{$_[0]};	1672	my ($pid, $cb) = @{$_[0]};
1324		1673
1325	delete $PID_CB{$pid}{$cb};	1674	delete $PID_CB{$pid}{$cb};
1326	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1675	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1327		1676
1328	undef $CHLD_W unless keys %PID_CB;	1677	undef $CHLD_W unless keys %PID_CB;
		1678	};
		1679	};
		1680	die if $@;
		1681
		1682	&child
1329	}	1683	}
1330		1684
1331	# idle emulation is done by simply using a timer, regardless	1685	# idle emulation is done by simply using a timer, regardless
1332	# of whether the process is idle or not, and not letting	1686	# of whether the process is idle or not, and not letting
1333	# the callback use more than 50% of the time.	1687	# the callback use more than 50% of the time.
1334	sub idle {	1688	sub idle {
		1689	eval q{ # poor man's autoloading {}
		1690	*idle = sub {
1335	my (undef, %arg) = @_;	1691	my (undef, %arg) = @_;
1336		1692
1337	my ($cb, $w, $rcb) = $arg{cb};	1693	my ($cb, $w, $rcb) = $arg{cb};
1338		1694
1339	$rcb = sub {	1695	$rcb = sub {
1340	if ($cb) {	1696	if ($cb) {
1341	$w = _time;	1697	$w = _time;
1342	&$cb;	1698	&$cb;
1343	$w = _time - $w;	1699	$w = _time - $w;
1344		1700
1345	# never use more then 50% of the time for the idle watcher,	1701	# never use more then 50% of the time for the idle watcher,
1346	# within some limits	1702	# within some limits
1347	$w = 0.0001 if $w < 0.0001;	1703	$w = 0.0001 if $w < 0.0001;
1348	$w = 5 if $w > 5;	1704	$w = 5 if $w > 5;
1349		1705
1350	$w = AnyEvent->timer (after => $w, cb => $rcb);	1706	$w = AE::timer $w, 0, $rcb;
1351	} else {	1707	} else {
1352	# clean up...	1708	# clean up...
1353	undef $w;	1709	undef $w;
1354	undef $rcb;	1710	undef $rcb;
		1711	}
		1712	};
		1713
		1714	$w = AE::timer 0.05, 0, $rcb;
		1715
		1716	bless \\$cb, "AnyEvent::Base::idle"
1355	}	1717	};
		1718
		1719	*AnyEvent::Base::idle::DESTROY = sub {
		1720	undef $${$_[0]};
		1721	};
1356	};	1722	};
		1723	die if $@;
1357		1724
1358	$w = AnyEvent->timer (after => 0.05, cb => $rcb);	1725	&idle
1359
1360	bless \\$cb, "AnyEvent::Base::idle"
1361	}
1362
1363	sub AnyEvent::Base::idle::DESTROY {
1364	undef $${$_[0]};
1365	}	1726	}
1366		1727
1367	package AnyEvent::CondVar;	1728	package AnyEvent::CondVar;
1368		1729
1369	our @ISA = AnyEvent::CondVar::Base::;	1730	our @ISA = AnyEvent::CondVar::Base::;
1370		1731
		1732	# only to be used for subclassing
		1733	sub new {
		1734	my $class = shift;
		1735	bless AnyEvent->condvar (@_), $class
		1736	}
		1737
1371	package AnyEvent::CondVar::Base;	1738	package AnyEvent::CondVar::Base;
1372		1739
1373	use overload	1740	#use overload
1374	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1741	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1375	fallback => 1;	1742	# fallback => 1;
		1743
		1744	# save 300+ kilobytes by dirtily hardcoding overloading
		1745	${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
		1746	*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
		1747	*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
		1748	${'AnyEvent::CondVar::Base::()'} = 1; # fallback
1376		1749
1377	our $WAITING;	1750	our $WAITING;
1378		1751
1379	sub _send {	1752	sub _send {
1380	# nop	1753	# nop
…		…
1411	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1784	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
1412	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1785	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
1413	}	1786	}
1414		1787
1415	sub cb {	1788	sub cb {
1416	$_[0]{_ae_cb} = $_[1] if @_ > 1;	1789	my $cv = shift;
		1790
		1791	@_
		1792	and $cv->{_ae_cb} = shift
		1793	and $cv->{_ae_sent}
		1794	and (delete $cv->{_ae_cb})->($cv);
		1795
1417	$_[0]{_ae_cb}	1796	$cv->{_ae_cb}
1418	}	1797	}
1419		1798
1420	sub begin {	1799	sub begin {
1421	++$_[0]{_ae_counter};	1800	++$_[0]{_ae_counter};
1422	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;	1801	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
…		…
1471	C<PERL_ANYEVENT_MODEL>.	1850	C<PERL_ANYEVENT_MODEL>.
1472		1851
1473	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	1852	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1474	model it chooses.	1853	model it chooses.
1475		1854
		1855	When set to C<8> or higher, then AnyEvent will report extra information on
		1856	which optional modules it loads and how it implements certain features.
		1857
1476	=item C<PERL_ANYEVENT_STRICT>	1858	=item C<PERL_ANYEVENT_STRICT>
1477		1859
1478	AnyEvent does not do much argument checking by default, as thorough	1860	AnyEvent does not do much argument checking by default, as thorough
1479	argument checking is very costly. Setting this variable to a true value	1861	argument checking is very costly. Setting this variable to a true value
1480	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly	1862	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1481	check the arguments passed to most method calls. If it finds any problems,	1863	check the arguments passed to most method calls. If it finds any problems,
1482	it will croak.	1864	it will croak.
1483		1865
1484	In other words, enables "strict" mode.	1866	In other words, enables "strict" mode.
1485		1867
1486	Unlike C<use strict>, it is definitely recommended to keep it off in	1868	Unlike C<use strict> (or its modern cousin, C<< use L<common::sense>
1487	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while	1869	>>, it is definitely recommended to keep it off in production. Keeping
1488	developing programs can be very useful, however.	1870	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
		1871	can be very useful, however.
1489		1872
1490	=item C<PERL_ANYEVENT_MODEL>	1873	=item C<PERL_ANYEVENT_MODEL>
1491		1874
1492	This can be used to specify the event model to be used by AnyEvent, before	1875	This can be used to specify the event model to be used by AnyEvent, before
1493	auto detection and -probing kicks in. It must be a string consisting	1876	auto detection and -probing kicks in. It must be a string consisting
…		…
1555		1938
1556	When neither C<ca_file> nor C<ca_path> was specified during	1939	When neither C<ca_file> nor C<ca_path> was specified during
1557	L<AnyEvent::TLS> context creation, and either of these environment	1940	L<AnyEvent::TLS> context creation, and either of these environment
1558	variables exist, they will be used to specify CA certificate locations	1941	variables exist, they will be used to specify CA certificate locations
1559	instead of a system-dependent default.	1942	instead of a system-dependent default.
		1943
		1944	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
		1945
		1946	When these are set to C<1>, then the respective modules are not
		1947	loaded. Mostly good for testing AnyEvent itself.
1560		1948
1561	=back	1949	=back
1562		1950
1563	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1951	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1564		1952
…		…
1622	warn "read: $input\n"; # output what has been read	2010	warn "read: $input\n"; # output what has been read
1623	$cv->send if $input =~ /^q/i; # quit program if /^q/i	2011	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1624	},	2012	},
1625	);	2013	);
1626		2014
1627	my $time_watcher; # can only be used once
1628
1629	sub new_timer {
1630	$timer = AnyEvent->timer (after => 1, cb => sub {	2015	my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1631	warn "timeout\n"; # print 'timeout' about every second	2016	warn "timeout\n"; # print 'timeout' at most every second
1632	&new_timer; # and restart the time
1633	});	2017	});
1634	}
1635
1636	new_timer; # create first timer
1637		2018
1638	$cv->recv; # wait until user enters /^q/i	2019	$cv->recv; # wait until user enters /^q/i
1639		2020
1640	=head1 REAL-WORLD EXAMPLE	2021	=head1 REAL-WORLD EXAMPLE
1641		2022
…		…
1714		2095
1715	The actual code goes further and collects all errors (C<die>s, exceptions)	2096	The actual code goes further and collects all errors (C<die>s, exceptions)
1716	that occurred during request processing. The C<result> method detects	2097	that occurred during request processing. The C<result> method detects
1717	whether an exception as thrown (it is stored inside the $txn object)	2098	whether an exception as thrown (it is stored inside the $txn object)
1718	and just throws the exception, which means connection errors and other	2099	and just throws the exception, which means connection errors and other
1719	problems get reported tot he code that tries to use the result, not in a	2100	problems get reported to the code that tries to use the result, not in a
1720	random callback.	2101	random callback.
1721		2102
1722	All of this enables the following usage styles:	2103	All of this enables the following usage styles:
1723		2104
1724	1. Blocking:	2105	1. Blocking:
…		…
1772	through AnyEvent. The benchmark creates a lot of timers (with a zero	2153	through AnyEvent. The benchmark creates a lot of timers (with a zero
1773	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	2154	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1774	which it is), lets them fire exactly once and destroys them again.	2155	which it is), lets them fire exactly once and destroys them again.
1775		2156
1776	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	2157	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1777	distribution.	2158	distribution. It uses the L<AE> interface, which makes a real difference
		2159	for the EV and Perl backends only.
1778		2160
1779	=head3 Explanation of the columns	2161	=head3 Explanation of the columns
1780		2162
1781	I<watcher> is the number of event watchers created/destroyed. Since	2163	I<watcher> is the number of event watchers created/destroyed. Since
1782	different event models feature vastly different performances, each event	2164	different event models feature vastly different performances, each event
…		…
1803	watcher.	2185	watcher.
1804		2186
1805	=head3 Results	2187	=head3 Results
1806		2188
1807	name watchers bytes create invoke destroy comment	2189	name watchers bytes create invoke destroy comment
1808	EV/EV 400000 224 0.47 0.35 0.27 EV native interface	2190	EV/EV 100000 223 0.47 0.43 0.27 EV native interface
1809	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	2191	EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
1810	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal	2192	Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
1811	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation	2193	Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
1812	Event/Event 16000 517 32.20 31.80 0.81 Event native interface	2194	Event/Event 16000 516 31.16 31.84 0.82 Event native interface
1813	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers	2195	Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
1814	IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll	2196	IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
1815	IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll	2197	IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
1816	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour	2198	Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
1817	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers	2199	Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
1818	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event	2200	POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
1819	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select	2201	POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
1820		2202
1821	=head3 Discussion	2203	=head3 Discussion
1822		2204
1823	The benchmark does I<not> measure scalability of the event loop very	2205	The benchmark does I<not> measure scalability of the event loop very
1824	well. For example, a select-based event loop (such as the pure perl one)	2206	well. For example, a select-based event loop (such as the pure perl one)
…		…
1836	benchmark machine, handling an event takes roughly 1600 CPU cycles with	2218	benchmark machine, handling an event takes roughly 1600 CPU cycles with
1837	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU	2219	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
1838	cycles with POE.	2220	cycles with POE.
1839		2221
1840	C<EV> is the sole leader regarding speed and memory use, which are both	2222	C<EV> is the sole leader regarding speed and memory use, which are both
1841	maximal/minimal, respectively. Even when going through AnyEvent, it uses	2223	maximal/minimal, respectively. When using the L<AE> API there is zero
		2224	overhead (when going through the AnyEvent API create is about 5-6 times
		2225	slower, with other times being equal, so still uses far less memory than
1842	far less memory than any other event loop and is still faster than Event	2226	any other event loop and is still faster than Event natively).
1843	natively.
1844		2227
1845	The pure perl implementation is hit in a few sweet spots (both the	2228	The pure perl implementation is hit in a few sweet spots (both the
1846	constant timeout and the use of a single fd hit optimisations in the perl	2229	constant timeout and the use of a single fd hit optimisations in the perl
1847	interpreter and the backend itself). Nevertheless this shows that it	2230	interpreter and the backend itself). Nevertheless this shows that it
1848	adds very little overhead in itself. Like any select-based backend its	2231	adds very little overhead in itself. Like any select-based backend its
…		…
1922	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100	2305	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1923	(1%) are active. This mirrors the activity of large servers with many	2306	(1%) are active. This mirrors the activity of large servers with many
1924	connections, most of which are idle at any one point in time.	2307	connections, most of which are idle at any one point in time.
1925		2308
1926	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	2309	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1927	distribution.	2310	distribution. It uses the L<AE> interface, which makes a real difference
		2311	for the EV and Perl backends only.
1928		2312
1929	=head3 Explanation of the columns	2313	=head3 Explanation of the columns
1930		2314
1931	I<sockets> is the number of sockets, and twice the number of "servers" (as	2315	I<sockets> is the number of sockets, and twice the number of "servers" (as
1932	each server has a read and write socket end).	2316	each server has a read and write socket end).
…		…
1940	a new one that moves the timeout into the future.	2324	a new one that moves the timeout into the future.
1941		2325
1942	=head3 Results	2326	=head3 Results
1943		2327
1944	name sockets create request	2328	name sockets create request
1945	EV 20000 69.01 11.16	2329	EV 20000 62.66 7.99
1946	Perl 20000 73.32 35.87	2330	Perl 20000 68.32 32.64
1947	IOAsync 20000 157.00 98.14 epoll	2331	IOAsync 20000 174.06 101.15 epoll
1948	IOAsync 20000 159.31 616.06 poll	2332	IOAsync 20000 174.67 610.84 poll
1949	Event 20000 212.62 257.32	2333	Event 20000 202.69 242.91
1950	Glib 20000 651.16 1896.30	2334	Glib 20000 557.01 1689.52
1951	POE 20000 349.67 12317.24 uses POE::Loop::Event	2335	POE 20000 341.54 12086.32 uses POE::Loop::Event
1952		2336
1953	=head3 Discussion	2337	=head3 Discussion
1954		2338
1955	This benchmark I<does> measure scalability and overall performance of the	2339	This benchmark I<does> measure scalability and overall performance of the
1956	particular event loop.	2340	particular event loop.
…		…
2082	As you can see, the AnyEvent + EV combination even beats the	2466	As you can see, the AnyEvent + EV combination even beats the
2083	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl	2467	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
2084	backend easily beats IO::Lambda and POE.	2468	backend easily beats IO::Lambda and POE.
2085		2469
2086	And even the 100% non-blocking version written using the high-level (and	2470	And even the 100% non-blocking version written using the high-level (and
2087	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a	2471	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
2088	large margin, even though it does all of DNS, tcp-connect and socket I/O	2472	higher level ("unoptimised") abstractions by a large margin, even though
2089	in a non-blocking way.	2473	it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
2090		2474
2091	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and	2475	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
2092	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are	2476	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
2093	part of the IO::lambda distribution and were used without any changes.	2477	part of the IO::Lambda distribution and were used without any changes.
2094		2478
2095		2479
2096	=head1 SIGNALS	2480	=head1 SIGNALS
2097		2481
2098	AnyEvent currently installs handlers for these signals:	2482	AnyEvent currently installs handlers for these signals:
…		…
2132	if $SIG{CHLD} eq 'IGNORE';	2516	if $SIG{CHLD} eq 'IGNORE';
2133		2517
2134	$SIG{PIPE} = sub { }	2518	$SIG{PIPE} = sub { }
2135	unless defined $SIG{PIPE};	2519	unless defined $SIG{PIPE};
2136		2520
		2521	=head1 RECOMMENDED/OPTIONAL MODULES
		2522
		2523	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
		2524	its built-in modules) are required to use it.
		2525
		2526	That does not mean that AnyEvent won't take advantage of some additional
		2527	modules if they are installed.
		2528
		2529	This section explains which additional modules will be used, and how they
		2530	affect AnyEvent's operation.
		2531
		2532	=over 4
		2533
		2534	=item L<Async::Interrupt>
		2535
		2536	This slightly arcane module is used to implement fast signal handling: To
		2537	my knowledge, there is no way to do completely race-free and quick
		2538	signal handling in pure perl. To ensure that signals still get
		2539	delivered, AnyEvent will start an interval timer to wake up perl (and
		2540	catch the signals) with some delay (default is 10 seconds, look for
		2541	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
		2542
		2543	If this module is available, then it will be used to implement signal
		2544	catching, which means that signals will not be delayed, and the event loop
		2545	will not be interrupted regularly, which is more efficient (and good for
		2546	battery life on laptops).
		2547
		2548	This affects not just the pure-perl event loop, but also other event loops
		2549	that have no signal handling on their own (e.g. Glib, Tk, Qt).
		2550
		2551	Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
		2552	and either employ their own workarounds (POE) or use AnyEvent's workaround
		2553	(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
		2554	does nothing for those backends.
		2555
		2556	=item L<EV>
		2557
		2558	This module isn't really "optional", as it is simply one of the backend
		2559	event loops that AnyEvent can use. However, it is simply the best event
		2560	loop available in terms of features, speed and stability: It supports
		2561	the AnyEvent API optimally, implements all the watcher types in XS, does
		2562	automatic timer adjustments even when no monotonic clock is available,
		2563	can take avdantage of advanced kernel interfaces such as C<epoll> and
		2564	C<kqueue>, and is the fastest backend I<by far>. You can even embed
		2565	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
		2566
		2567	If you only use backends that rely on another event loop (e.g. C<Tk>),
		2568	then this module will do nothing for you.
		2569
		2570	=item L<Guard>
		2571
		2572	The guard module, when used, will be used to implement
		2573	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
		2574	lot less memory), but otherwise doesn't affect guard operation much. It is
		2575	purely used for performance.
		2576
		2577	=item L<JSON> and L<JSON::XS>
		2578
		2579	One of these modules is required when you want to read or write JSON data
		2580	via L<AnyEvent::Handle>. L<JSON> is also written in pure-perl, but can take
		2581	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
		2582
		2583	=item L<Net::SSLeay>
		2584
		2585	Implementing TLS/SSL in Perl is certainly interesting, but not very
		2586	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
		2587	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
		2588
		2589	=item L<Time::HiRes>
		2590
		2591	This module is part of perl since release 5.008. It will be used when the
		2592	chosen event library does not come with a timing source of its own. The
		2593	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
		2594	try to use a monotonic clock for timing stability.
		2595
		2596	=back
		2597
		2598
2137	=head1 FORK	2599	=head1 FORK
2138		2600
2139	Most event libraries are not fork-safe. The ones who are usually are	2601	Most event libraries are not fork-safe. The ones who are usually are
2140	because they rely on inefficient but fork-safe C<select> or C<poll>	2602	because they rely on inefficient but fork-safe C<select> or C<poll> calls
2141	calls. Only L<EV> is fully fork-aware.	2603	- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
		2604	are usually badly thought-out hacks that are incompatible with fork in
		2605	one way or another. Only L<EV> is fully fork-aware and ensures that you
		2606	continue event-processing in both parent and child (or both, if you know
		2607	what you are doing).
		2608
		2609	This means that, in general, you cannot fork and do event processing in
		2610	the child if the event library was initialised before the fork (which
		2611	usually happens when the first AnyEvent watcher is created, or the library
		2612	is loaded).
2142		2613
2143	If you have to fork, you must either do so I<before> creating your first	2614	If you have to fork, you must either do so I<before> creating your first
2144	watcher OR you must not use AnyEvent at all in the child.	2615	watcher OR you must not use AnyEvent at all in the child OR you must do
		2616	something completely out of the scope of AnyEvent.
		2617
		2618	The problem of doing event processing in the parent I<and> the child
		2619	is much more complicated: even for backends that I<are> fork-aware or
		2620	fork-safe, their behaviour is not usually what you want: fork clones all
		2621	watchers, that means all timers, I/O watchers etc. are active in both
		2622	parent and child, which is almost never what you want. USing C<exec>
		2623	to start worker children from some kind of manage rprocess is usually
		2624	preferred, because it is much easier and cleaner, at the expense of having
		2625	to have another binary.
2145		2626
2146		2627
2147	=head1 SECURITY CONSIDERATIONS	2628	=head1 SECURITY CONSIDERATIONS
2148		2629
2149	AnyEvent can be forced to load any event model via	2630	AnyEvent can be forced to load any event model via
…		…
2179	pronounced).	2660	pronounced).
2180		2661
2181		2662
2182	=head1 SEE ALSO	2663	=head1 SEE ALSO
2183		2664
		2665	Tutorial/Introduction: L<AnyEvent::Intro>.
		2666
		2667	FAQ: L<AnyEvent::FAQ>.
		2668
2184	Utility functions: L<AnyEvent::Util>.	2669	Utility functions: L<AnyEvent::Util>.
2185		2670
2186	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,	2671	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,
2187	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2672	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
2188		2673
2189	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2674	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
2190	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2675	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
2191	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2676	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
2192	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>.	2677	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.
2193		2678
2194	Non-blocking file handles, sockets, TCP clients and	2679	Non-blocking file handles, sockets, TCP clients and
2195	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.	2680	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2196		2681
2197	Asynchronous DNS: L<AnyEvent::DNS>.	2682	Asynchronous DNS: L<AnyEvent::DNS>.
2198		2683
2199	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,	2684	Thread support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>.
2200	L<Coro::Event>,
2201		2685
2202	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,	2686	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::IRC>,
2203	L<AnyEvent::HTTP>.	2687	L<AnyEvent::HTTP>.
2204		2688
2205		2689
2206	=head1 AUTHOR	2690	=head1 AUTHOR
2207		2691

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