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Revision 1.251 by root, Mon Jul 20 22:39:57 2009 UTC vs.
Revision 1.347 by root, Sun Jan 23 11:15:09 2011 UTC

1	=head1 NAME	1	=head1 NAME
2		2
3	AnyEvent - events independent of event loop implementation	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
…		…
43	in a tutorial or some gentle introduction, have a look at the	46	in a tutorial or some gentle introduction, have a look at the
44	L<AnyEvent::Intro> manpage.	47	L<AnyEvent::Intro> manpage.
45		48
46	=head1 SUPPORT	49	=head1 SUPPORT
47		50
		51	An FAQ document is available as L<AnyEvent::FAQ>.
		52
48	There is a mailinglist for discussing all things AnyEvent, and an IRC	53	There also is a mailinglist for discussing all things AnyEvent, and an IRC
49	channel, too.	54	channel, too.
50		55
51	See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software	56	See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software
52	Respository>, at L<http://anyevent.schmorp.de>, for more info.	57	Repository>, at L<http://anyevent.schmorp.de>, for more info.
53		58
54	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)	59	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
55		60
56	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
57	nowadays. So what is different about AnyEvent?	62	nowadays. So what is different about AnyEvent?
…		…
73	module users into the same thing by forcing them to use the same event	78	module users into the same thing by forcing them to use the same event
74	model you use.	79	model you use.
75		80
76	For modules like POE or IO::Async (which is a total misnomer as it is	81	For modules like POE or IO::Async (which is a total misnomer as it is
77	actually doing all I/O I<synchronously>...), using them in your module is	82	actually doing all I/O I<synchronously>...), using them in your module is
78	like joining a cult: After you joined, you are dependent on them and you	83	like joining a cult: After you join, you are dependent on them and you
79	cannot use anything else, as they are simply incompatible to everything	84	cannot use anything else, as they are simply incompatible to everything
80	that isn't them. What's worse, all the potential users of your	85	that isn't them. What's worse, all the potential users of your
81	module are I<also> forced to use the same event loop you use.	86	module are I<also> forced to use the same event loop you use.
82		87
83	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works	88	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
84	fine. AnyEvent + Tk works fine etc. etc. but none of these work together	89	fine. AnyEvent + Tk works fine etc. etc. but none of these work together
85	with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if	90	with the rest: POE + EV? No go. Tk + Event? No go. Again: if your module
86	your module uses one of those, every user of your module has to use it,	91	uses one of those, every user of your module has to use it, too. But if
87	too. But if your module uses AnyEvent, it works transparently with all	92	your module uses AnyEvent, it works transparently with all event models it
88	event models it supports (including stuff like IO::Async, as long as those	93	supports (including stuff like IO::Async, as long as those use one of the
89	use one of the supported event loops. It is trivial to add new event loops	94	supported event loops. It is easy to add new event loops to AnyEvent, too,
90	to AnyEvent, too, so it is future-proof).	95	so it is future-proof).
91		96
92	In addition to being free of having to use I<the one and only true event	97	In addition to being free of having to use I<the one and only true event
93	model>, AnyEvent also is free of bloat and policy: with POE or similar	98	model>, AnyEvent also is free of bloat and policy: with POE or similar
94	modules, you get an enormous amount of code and strict rules you have to	99	modules, you get an enormous amount of code and strict rules you have to
95	follow. AnyEvent, on the other hand, is lean and up to the point, by only	100	follow. AnyEvent, on the other hand, is lean and to the point, by only
96	offering the functionality that is necessary, in as thin as a wrapper as	101	offering the functionality that is necessary, in as thin as a wrapper as
97	technically possible.	102	technically possible.
98		103
99	Of course, AnyEvent comes with a big (and fully optional!) toolbox	104	Of course, AnyEvent comes with a big (and fully optional!) toolbox
100	of useful functionality, such as an asynchronous DNS resolver, 100%	105	of useful functionality, such as an asynchronous DNS resolver, 100%
…		…
106	useful) and you want to force your users to use the one and only event	111	useful) and you want to force your users to use the one and only event
107	model, you should I<not> use this module.	112	model, you should I<not> use this module.
108		113
109	=head1 DESCRIPTION	114	=head1 DESCRIPTION
110		115
111	L<AnyEvent> provides an identical interface to multiple event loops. This	116	L<AnyEvent> provides a uniform interface to various event loops. This
112	allows module authors to utilise an event loop without forcing module	117	allows module authors to use event loop functionality without forcing
113	users to use the same event loop (as only a single event loop can coexist	118	module users to use a specific event loop implementation (since more
114	peacefully at any one time).	119	than one event loop cannot coexist peacefully).
115		120
116	The interface itself is vaguely similar, but not identical to the L<Event>	121	The interface itself is vaguely similar, but not identical to the L<Event>
117	module.	122	module.
118		123
119	During the first call of any watcher-creation method, the module tries	124	During the first call of any watcher-creation method, the module tries
120	to detect the currently loaded event loop by probing whether one of the	125	to detect the currently loaded event loop by probing whether one of the
121	following modules is already loaded: L<EV>,	126	following modules is already loaded: L<EV>, L<AnyEvent::Impl::Perl>,
122	L<Event>, L<Glib>, L<AnyEvent::Impl::Perl>, L<Tk>, L<Event::Lib>, L<Qt>,	127	L<Event>, L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. The first one
123	L<POE>. The first one found is used. If none are found, the module tries	128	found is used. If none are detected, the module tries to load the first
124	to load these modules (excluding Tk, Event::Lib, Qt and POE as the pure perl	129	four modules in the order given; but note that if L<EV> is not
125	adaptor should always succeed) in the order given. The first one that can	130	available, the pure-perl L<AnyEvent::Impl::Perl> should always work, so
126	be successfully loaded will be used. If, after this, still none could be	131	the other two are not normally tried.
127	found, AnyEvent will fall back to a pure-perl event loop, which is not
128	very efficient, but should work everywhere.
129		132
130	Because AnyEvent first checks for modules that are already loaded, loading	133	Because AnyEvent first checks for modules that are already loaded, loading
131	an event model explicitly before first using AnyEvent will likely make	134	an event model explicitly before first using AnyEvent will likely make
132	that model the default. For example:	135	that model the default. For example:
133		136
…		…
135	use AnyEvent;	138	use AnyEvent;
136		139
137	# .. AnyEvent will likely default to Tk	140	# .. AnyEvent will likely default to Tk
138		141
139	The I<likely> means that, if any module loads another event model and	142	The I<likely> means that, if any module loads another event model and
140	starts using it, all bets are off. Maybe you should tell their authors to	143	starts using it, all bets are off - this case should be very rare though,
141	use AnyEvent so their modules work together with others seamlessly...	144	as very few modules hardcode event loops without announcing this very
		145	loudly.
142		146
143	The pure-perl implementation of AnyEvent is called	147	The pure-perl implementation of AnyEvent is called
144	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
145	explicitly and enjoy the high availability of that event loop :)	149	explicitly and enjoy the high availability of that event loop :)
146		150
…		…
155	callback when the event occurs (of course, only when the event model	159	callback when the event occurs (of course, only when the event model
156	is in control).	160	is in control).
157		161
158	Note that B<callbacks must not permanently change global variables>	162	Note that B<callbacks must not permanently change global variables>
159	potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<	163	potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<
160	callbacks must not C<die> >>. The former is good programming practise in	164	callbacks must not C<die> >>. The former is good programming practice in
161	Perl and the latter stems from the fact that exception handling differs	165	Perl and the latter stems from the fact that exception handling differs
162	widely between event loops.	166	widely between event loops.
163		167
164	To disable the watcher you have to destroy it (e.g. by setting the	168	To disable a watcher you have to destroy it (e.g. by setting the
165	variable you store it in to C<undef> or otherwise deleting all references	169	variable you store it in to C<undef> or otherwise deleting all references
166	to it).	170	to it).
167		171
168	All watchers are created by calling a method on the C<AnyEvent> class.	172	All watchers are created by calling a method on the C<AnyEvent> class.
169		173
170	Many watchers either are used with "recursion" (repeating timers for	174	Many watchers either are used with "recursion" (repeating timers for
171	example), or need to refer to their watcher object in other ways.	175	example), or need to refer to their watcher object in other ways.
172		176
173	An any way to achieve that is this pattern:	177	One way to achieve that is this pattern:
174		178
175	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {	179	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
176	# you can use $w here, for example to undef it	180	# you can use $w here, for example to undef it
177	undef $w;	181	undef $w;
178	});	182	});
…		…
180	Note that C<my $w; $w => combination. This is necessary because in Perl,	184	Note that C<my $w; $w => combination. This is necessary because in Perl,
181	my variables are only visible after the statement in which they are	185	my variables are only visible after the statement in which they are
182	declared.	186	declared.
183		187
184	=head2 I/O WATCHERS	188	=head2 I/O WATCHERS
		189
		190	$w = AnyEvent->io (
		191	fh => <filehandle_or_fileno>,
		192	poll => <"r" or "w">,
		193	cb => <callback>,
		194	);
185		195
186	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	196	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
187	with the following mandatory key-value pairs as arguments:	197	with the following mandatory key-value pairs as arguments:
188		198
189	C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch	199	C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch
…		…
204		214
205	The I/O watcher might use the underlying file descriptor or a copy of it.	215	The I/O watcher might use the underlying file descriptor or a copy of it.
206	You must not close a file handle as long as any watcher is active on the	216	You must not close a file handle as long as any watcher is active on the
207	underlying file descriptor.	217	underlying file descriptor.
208		218
209	Some event loops issue spurious readyness notifications, so you should	219	Some event loops issue spurious readiness notifications, so you should
210	always use non-blocking calls when reading/writing from/to your file	220	always use non-blocking calls when reading/writing from/to your file
211	handles.	221	handles.
212		222
213	Example: wait for readability of STDIN, then read a line and disable the	223	Example: wait for readability of STDIN, then read a line and disable the
214	watcher.	224	watcher.
…		…
219	undef $w;	229	undef $w;
220	});	230	});
221		231
222	=head2 TIME WATCHERS	232	=head2 TIME WATCHERS
223		233
		234	$w = AnyEvent->timer (after => <seconds>, cb => <callback>);
		235
		236	$w = AnyEvent->timer (
		237	after => <fractional_seconds>,
		238	interval => <fractional_seconds>,
		239	cb => <callback>,
		240	);
		241
224	You can create a time watcher by calling the C<< AnyEvent->timer >>	242	You can create a time watcher by calling the C<< AnyEvent->timer >>
225	method with the following mandatory arguments:	243	method with the following mandatory arguments:
226		244
227	C<after> specifies after how many seconds (fractional values are	245	C<after> specifies after how many seconds (fractional values are
228	supported) the callback should be invoked. C<cb> is the callback to invoke	246	supported) the callback should be invoked. C<cb> is the callback to invoke
…		…
230		248
231	Although the callback might get passed parameters, their value and	249	Although the callback might get passed parameters, their value and
232	presence is undefined and you cannot rely on them. Portable AnyEvent	250	presence is undefined and you cannot rely on them. Portable AnyEvent
233	callbacks cannot use arguments passed to time watcher callbacks.	251	callbacks cannot use arguments passed to time watcher callbacks.
234		252
235	The callback will normally be invoked once only. If you specify another	253	The callback will normally be invoked only once. If you specify another
236	parameter, C<interval>, as a strictly positive number (> 0), then the	254	parameter, C<interval>, as a strictly positive number (> 0), then the
237	callback will be invoked regularly at that interval (in fractional	255	callback will be invoked regularly at that interval (in fractional
238	seconds) after the first invocation. If C<interval> is specified with a	256	seconds) after the first invocation. If C<interval> is specified with a
239	false value, then it is treated as if it were missing.	257	false value, then it is treated as if it were not specified at all.
240		258
241	The callback will be rescheduled before invoking the callback, but no	259	The callback will be rescheduled before invoking the callback, but no
242	attempt is done to avoid timer drift in most backends, so the interval is	260	attempt is made to avoid timer drift in most backends, so the interval is
243	only approximate.	261	only approximate.
244		262
245	Example: fire an event after 7.7 seconds.	263	Example: fire an event after 7.7 seconds.
246		264
247	my $w = AnyEvent->timer (after => 7.7, cb => sub {	265	my $w = AnyEvent->timer (after => 7.7, cb => sub {
…		…
265		283
266	While most event loops expect timers to specified in a relative way, they	284	While most event loops expect timers to specified in a relative way, they
267	use absolute time internally. This makes a difference when your clock	285	use absolute time internally. This makes a difference when your clock
268	"jumps", for example, when ntp decides to set your clock backwards from	286	"jumps", for example, when ntp decides to set your clock backwards from
269	the wrong date of 2014-01-01 to 2008-01-01, a watcher that is supposed to	287	the wrong date of 2014-01-01 to 2008-01-01, a watcher that is supposed to
270	fire "after" a second might actually take six years to finally fire.	288	fire "after a second" might actually take six years to finally fire.
271		289
272	AnyEvent cannot compensate for this. The only event loop that is conscious	290	AnyEvent cannot compensate for this. The only event loop that is conscious
273	about these issues is L<EV>, which offers both relative (ev_timer, based	291	of these issues is L<EV>, which offers both relative (ev_timer, based
274	on true relative time) and absolute (ev_periodic, based on wallclock time)	292	on true relative time) and absolute (ev_periodic, based on wallclock time)
275	timers.	293	timers.
276		294
277	AnyEvent always prefers relative timers, if available, matching the	295	AnyEvent always prefers relative timers, if available, matching the
278	AnyEvent API.	296	AnyEvent API.
…		…
300	I<In almost all cases (in all cases if you don't care), this is the	318	I<In almost all cases (in all cases if you don't care), this is the
301	function to call when you want to know the current time.>	319	function to call when you want to know the current time.>
302		320
303	This function is also often faster then C<< AnyEvent->time >>, and	321	This function is also often faster then C<< AnyEvent->time >>, and
304	thus the preferred method if you want some timestamp (for example,	322	thus the preferred method if you want some timestamp (for example,
305	L<AnyEvent::Handle> uses this to update it's activity timeouts).	323	L<AnyEvent::Handle> uses this to update its activity timeouts).
306		324
307	The rest of this section is only of relevance if you try to be very exact	325	The rest of this section is only of relevance if you try to be very exact
308	with your timing, you can skip it without bad conscience.	326	with your timing; you can skip it without a bad conscience.
309		327
310	For a practical example of when these times differ, consider L<Event::Lib>	328	For a practical example of when these times differ, consider L<Event::Lib>
311	and L<EV> and the following set-up:	329	and L<EV> and the following set-up:
312		330
313	The event loop is running and has just invoked one of your callback at	331	The event loop is running and has just invoked one of your callbacks at
314	time=500 (assume no other callbacks delay processing). In your callback,	332	time=500 (assume no other callbacks delay processing). In your callback,
315	you wait a second by executing C<sleep 1> (blocking the process for a	333	you wait a second by executing C<sleep 1> (blocking the process for a
316	second) and then (at time=501) you create a relative timer that fires	334	second) and then (at time=501) you create a relative timer that fires
317	after three seconds.	335	after three seconds.
318		336
…		…
349	might affect timers and time-outs.	367	might affect timers and time-outs.
350		368
351	When this is the case, you can call this method, which will update the	369	When this is the case, you can call this method, which will update the
352	event loop's idea of "current time".	370	event loop's idea of "current time".
353		371
		372	A typical example would be a script in a web server (e.g. C<mod_perl>) -
		373	when mod_perl executes the script, then the event loop will have the wrong
		374	idea about the "current time" (being potentially far in the past, when the
		375	script ran the last time). In that case you should arrange a call to C<<
		376	AnyEvent->now_update >> each time the web server process wakes up again
		377	(e.g. at the start of your script, or in a handler).
		378
354	Note that updating the time I<might> cause some events to be handled.	379	Note that updating the time I<might> cause some events to be handled.
355		380
356	=back	381	=back
357		382
358	=head2 SIGNAL WATCHERS	383	=head2 SIGNAL WATCHERS
		384
		385	$w = AnyEvent->signal (signal => <uppercase_signal_name>, cb => <callback>);
359		386
360	You can watch for signals using a signal watcher, C<signal> is the signal	387	You can watch for signals using a signal watcher, C<signal> is the signal
361	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl	388	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
362	callback to be invoked whenever a signal occurs.	389	callback to be invoked whenever a signal occurs.
363		390
…		…
380		407
381	Example: exit on SIGINT	408	Example: exit on SIGINT
382		409
383	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });	410	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
384		411
		412	=head3 Restart Behaviour
		413
		414	While restart behaviour is up to the event loop implementation, most will
		415	not restart syscalls (that includes L<Async::Interrupt> and AnyEvent's
		416	pure perl implementation).
		417
		418	=head3 Safe/Unsafe Signals
		419
		420	Perl signals can be either "safe" (synchronous to opcode handling) or
		421	"unsafe" (asynchronous) - the former might get delayed indefinitely, the
		422	latter might corrupt your memory.
		423
		424	AnyEvent signal handlers are, in addition, synchronous to the event loop,
		425	i.e. they will not interrupt your running perl program but will only be
		426	called as part of the normal event handling (just like timer, I/O etc.
		427	callbacks, too).
		428
385	=head3 Signal Races, Delays and Workarounds	429	=head3 Signal Races, Delays and Workarounds
386		430
387	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching	431	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
388	callbacks to signals in a generic way, which is a pity, as you cannot do	432	callbacks to signals in a generic way, which is a pity, as you cannot
389	race-free signal handling in perl. AnyEvent will try to do it's best, but	433	do race-free signal handling in perl, requiring C libraries for
		434	this. AnyEvent will try to do its best, which means in some cases,
390	in some cases, signals will be delayed. The maximum time a signal might	435	signals will be delayed. The maximum time a signal might be delayed is
391	be delayed is specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10	436	specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This
392	seconds). This variable can be changed only before the first signal	437	variable can be changed only before the first signal watcher is created,
393	watcher is created, and should be left alone otherwise. Higher values	438	and should be left alone otherwise. This variable determines how often
		439	AnyEvent polls for signals (in case a wake-up was missed). Higher values
394	will cause fewer spurious wake-ups, which is better for power and CPU	440	will cause fewer spurious wake-ups, which is better for power and CPU
		441	saving.
		442
395	saving. All these problems can be avoided by installing the optional	443	All these problems can be avoided by installing the optional
396	L<Async::Interrupt> module. This will not work with inherently broken	444	L<Async::Interrupt> module, which works with most event loops. It will not
397	event loops such as L<Event> or L<Event::Lib> (and not with L<POE>	445	work with inherently broken event loops such as L<Event> or L<Event::Lib>
398	currently, as POE does it's own workaround with one-second latency). With	446	(and not with L<POE> currently, as POE does its own workaround with
399	those, you just have to suffer the delays.	447	one-second latency). For those, you just have to suffer the delays.
400		448
401	=head2 CHILD PROCESS WATCHERS	449	=head2 CHILD PROCESS WATCHERS
402		450
		451	$w = AnyEvent->child (pid => <process id>, cb => <callback>);
		452
403	You can also watch on a child process exit and catch its exit status.	453	You can also watch for a child process exit and catch its exit status.
404		454
405	The child process is specified by the C<pid> argument (if set to C<0>, it	455	The child process is specified by the C<pid> argument (on some backends,
406	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
407	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
408	any trace events (stopped/continued).	458	finished and an exit status is available, not on any trace events
		459	(stopped/continued).
409		460
410	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
411	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
412	callback arguments.	463	callback arguments.
413		464
…		…
454	# do something else, then wait for process exit	505	# do something else, then wait for process exit
455	$done->recv;	506	$done->recv;
456		507
457	=head2 IDLE WATCHERS	508	=head2 IDLE WATCHERS
458		509
459	Sometimes there is a need to do something, but it is not so important	510	$w = AnyEvent->idle (cb => <callback>);
460	to do it instantly, but only when there is nothing better to do. This
461	"nothing better to do" is usually defined to be "no other events need
462	attention by the event loop".
463		511
464	Idle watchers ideally get invoked when the event loop has nothing	512	This will repeatedly invoke the callback after the process becomes idle,
465	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.
466	events. Instead of blocking, the idle watcher is invoked.
467		514
468	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
469	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
470	will simply call the callback "from time to time".	526	will simply call the callback "from time to time".
471		527
472	Example: read lines from STDIN, but only process them when the	528	Example: read lines from STDIN, but only process them when the
473	program is otherwise idle:	529	program is otherwise idle:
…		…
489	});	545	});
490	});	546	});
491		547
492	=head2 CONDITION VARIABLES	548	=head2 CONDITION VARIABLES
493		549
		550	$cv = AnyEvent->condvar;
		551
		552	$cv->send (<list>);
		553	my @res = $cv->recv;
		554
494	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
495	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
496	will actively watch for new events and call your callbacks.	557	will actively watch for new events and call your callbacks.
497		558
498	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
499	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).
500		561
501	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
502	because they represent a condition that must become true.	563	they represent a condition that must become true.
503		564
504	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.
505		566
506	Condition variables can be created by calling the C<< AnyEvent->condvar	567	Condition variables can be created by calling the C<< AnyEvent->condvar
507	>> method, usually without arguments. The only argument pair allowed is	568	>> method, usually without arguments. The only argument pair allowed is
…		…
512	After creation, the condition variable is "false" until it becomes "true"	573	After creation, the condition variable is "false" until it becomes "true"
513	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
514	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<<
515	->send >> method).	576	->send >> method).
516		577
517	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
518	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:
519	in time where multiple outstanding events have been processed. And yet	580
520	another way to call them is transactions - each condition variable can be	581	=over 4
521	used to represent a transaction, which finishes at some point and delivers	582
522	a result. And yet some people know them as "futures" - a promise to	583	=item * Condition variables are like callbacks - you can call them (and pass them instead
523	compute/deliver something that you can wait for.	584	of callbacks). Unlike callbacks however, you can also wait for them to be called.
		585
		586	=item * Condition variables are signals - one side can emit or send them,
		587	the other side can wait for them, or install a handler that is called when
		588	the signal fires.
		589
		590	=item * Condition variables are like "Merge Points" - points in your program
		591	where you merge multiple independent results/control flows into one.
		592
		593	=item * Condition variables represent a transaction - functions that start
		594	some kind of transaction can return them, leaving the caller the choice
		595	between waiting in a blocking fashion, or setting a callback.
		596
		597	=item * Condition variables represent future values, or promises to deliver
		598	some result, long before the result is available.
		599
		600	=back
524		601
525	Condition variables are very useful to signal that something has finished,	602	Condition variables are very useful to signal that something has finished,
526	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,
527	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
528	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
…		…
541		618
542	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
543	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
544	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
545	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
546	it's C<new> method in your own C<new> method.	623	its C<new> method in your own C<new> method.
547		624
548	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
549	eventually calls C<< -> send >>, and the "consumer side", which waits	626	eventually calls C<< -> send >>, and the "consumer side", which waits
550	for the send to occur.	627	for the send to occur.
551		628
552	Example: wait for a timer.	629	Example: wait for a timer.
553		630
554	# wait till the result is ready	631	# condition: "wait till the timer is fired"
555	my $result_ready = AnyEvent->condvar;	632	my $timer_fired = AnyEvent->condvar;
556		633
557	# do something such as adding a timer	634	# create the timer - we could wait for, say
558	# or socket watcher the calls $result_ready->send	635	# a handle becomign ready, or even an
559	# when the "result" is ready.	636	# AnyEvent::HTTP request to finish, but
560	# in this case, we simply use a timer:	637	# in this case, we simply use a timer:
561	my $w = AnyEvent->timer (	638	my $w = AnyEvent->timer (
562	after => 1,	639	after => 1,
563	cb => sub { $result_ready->send },	640	cb => sub { $timer_fired->send },
564	);	641	);
565		642
566	# this "blocks" (while handling events) till the callback	643	# this "blocks" (while handling events) till the callback
567	# calls -<send	644	# calls ->send
568	$result_ready->recv;	645	$timer_fired->recv;
569		646
570	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
571	variables are also callable directly.	648	variables are also callable directly.
572		649
573	my $done = AnyEvent->condvar;	650	my $done = AnyEvent->condvar;
…		…
616	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
617	C<send>.	694	C<send>.
618		695
619	=item $cv->croak ($error)	696	=item $cv->croak ($error)
620		697
621	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
622	C<Carp::croak> with the given error message/object/scalar.	699	C<Carp::croak> with the given error message/object/scalar.
623		700
624	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
625	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
626	delays the error detetcion, but has the overwhelmign advantage that it	703	delays the error detection, but has the overwhelming advantage that it
627	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
628	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
629	the problem.	706	the problem.
630		707
631	=item $cv->begin ([group callback])	708	=item $cv->begin ([group callback])
632		709
633	=item $cv->end	710	=item $cv->end
…		…
636	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
637	to use a condition variable for the whole process.	714	to use a condition variable for the whole process.
638		715
639	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
640	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
641	>>, 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
642	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
643	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.
644		722
645	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
646	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
647	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).
648		726
…		…
670	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
671	sending.	749	sending.
672		750
673	The ping example mentioned above is slightly more complicated, as the	751	The ping example mentioned above is slightly more complicated, as the
674	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
675	begung can potentially be zero:	753	begun can potentially be zero:
676		754
677	my $cv = AnyEvent->condvar;	755	my $cv = AnyEvent->condvar;
678		756
679	my %result;	757	my %result;
680	$cv->begin (sub { $cv->send (\%result) });	758	$cv->begin (sub { shift->send (\%result) });
681		759
682	for my $host (@list_of_hosts) {	760	for my $host (@list_of_hosts) {
683	$cv->begin;	761	$cv->begin;
684	ping_host_then_call_callback $host, sub {	762	ping_host_then_call_callback $host, sub {
685	$result{$host} = ...;	763	$result{$host} = ...;
…		…
701	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
702	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
703	doesn't execute once).	781	doesn't execute once).
704		782
705	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
706	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
707	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
708	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,
709	call C<end>.	787	call C<end>.
710		788
711	=back	789	=back
…		…
718	=over 4	796	=over 4
719		797
720	=item $cv->recv	798	=item $cv->recv
721		799
722	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak	800	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
723	>> methods have been called on c<$cv>, while servicing other watchers	801	>> methods have been called on C<$cv>, while servicing other watchers
724	normally.	802	normally.
725		803
726	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
727	will return immediately.	805	will return immediately.
728		806
…		…
745	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
746	condition variables with some kind of request results and supporting	824	condition variables with some kind of request results and supporting
747	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,
748	while still supporting blocking waits if the caller so desires).	826	while still supporting blocking waits if the caller so desires).
749		827
750	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
751	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
752	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
753	waits otherwise.	831	waits otherwise.
754		832
755	=item $bool = $cv->ready	833	=item $bool = $cv->ready
…		…
761		839
762	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
763	replaces it before doing so.	841	replaces it before doing so.
764		842
765	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
766	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
767	variable itself. Calling C<recv> inside the callback or at any later time	845	condition variable itself. If the condition is already true, the
768	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.
769		848
770	=back	849	=back
771		850
772	=head1 SUPPORTED EVENT LOOPS/BACKENDS	851	=head1 SUPPORTED EVENT LOOPS/BACKENDS
773		852
…		…
776	=over 4	855	=over 4
777		856
778	=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.
779		858
780	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
781	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
782	that, will fall back to its own pure-perl implementation, which is	861	pure-perl implementation, which is available everywhere as it comes with
783	available everywhere as it comes with AnyEvent itself.	862	AnyEvent itself.
784		863
785	AnyEvent::Impl::EV based on EV (interface to libev, best choice).	864	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
786	AnyEvent::Impl::Event based on Event, very stable, few glitches.
787	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.	865	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
788		866
789	=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.
790		868
791	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
792	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
793	them. This means that AnyEvent will automatically pick the right backend	871	them. This means that AnyEvent will automatically pick the right backend
794	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
795	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.
796		874
		875	AnyEvent::Impl::Event based on Event, very stable, few glitches.
797	AnyEvent::Impl::Glib based on Glib, slow but very stable.	876	AnyEvent::Impl::Glib based on Glib, slow but very stable.
798	AnyEvent::Impl::Tk based on Tk, very broken.	877	AnyEvent::Impl::Tk based on Tk, very broken.
799	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.	878	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
800	AnyEvent::Impl::POE based on POE, very slow, some limitations.	879	AnyEvent::Impl::POE based on POE, very slow, some limitations.
		880	AnyEvent::Impl::Irssi used when running within irssi.
		881	AnyEvent::Impl::IOAsync based on IO::Async.
		882	AnyEvent::Impl::Cocoa based on Cocoa::EventLoop.
801		883
802	=item Backends with special needs.	884	=item Backends with special needs.
803		885
804	Qt requires the Qt::Application to be instantiated first, but will	886	Qt requires the Qt::Application to be instantiated first, but will
805	otherwise be picked up automatically. As long as the main program	887	otherwise be picked up automatically. As long as the main program
806	instantiates the application before any AnyEvent watchers are created,	888	instantiates the application before any AnyEvent watchers are created,
807	everything should just work.	889	everything should just work.
808		890
809	AnyEvent::Impl::Qt based on Qt.	891	AnyEvent::Impl::Qt based on Qt.
810		892
811	Support for IO::Async can only be partial, as it is too broken and
812	architecturally limited to even support the AnyEvent API. It also
813	is the only event loop that needs the loop to be set explicitly, so
814	it can only be used by a main program knowing about AnyEvent. See
815	L<AnyEvent::Impl::Async> for the gory details.
816
817	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
818
819	=item Event loops that are indirectly supported via other backends.	893	=item Event loops that are indirectly supported via other backends.
820		894
821	Some event loops can be supported via other modules:	895	Some event loops can be supported via other modules:
822		896
823	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.	897	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
…		…
848	Contains C<undef> until the first watcher is being created, before the	922	Contains C<undef> until the first watcher is being created, before the
849	backend has been autodetected.	923	backend has been autodetected.
850		924
851	Afterwards it contains the event model that is being used, which is the	925	Afterwards it contains the event model that is being used, which is the
852	name of the Perl class implementing the model. This class is usually one	926	name of the Perl class implementing the model. This class is usually one
853	of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the	927	of the C<AnyEvent::Impl::xxx> modules, but can be any other class in the
854	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it	928	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
855	will be C<urxvt::anyevent>).	929	will be C<urxvt::anyevent>).
856		930
857	=item AnyEvent::detect	931	=item AnyEvent::detect
858		932
859	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	933	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
860	if necessary. You should only call this function right before you would	934	if necessary. You should only call this function right before you would
861	have created an AnyEvent watcher anyway, that is, as late as possible at	935	have created an AnyEvent watcher anyway, that is, as late as possible at
862	runtime, and not e.g. while initialising of your module.	936	runtime, and not e.g. during initialisation of your module.
863		937
864	If you need to do some initialisation before AnyEvent watchers are	938	If you need to do some initialisation before AnyEvent watchers are
865	created, use C<post_detect>.	939	created, use C<post_detect>.
866		940
867	=item $guard = AnyEvent::post_detect { BLOCK }	941	=item $guard = AnyEvent::post_detect { BLOCK }
868		942
869	Arranges for the code block to be executed as soon as the event model is	943	Arranges for the code block to be executed as soon as the event model is
870	autodetected (or immediately if this has already happened).	944	autodetected (or immediately if that has already happened).
871		945
872	The block will be executed I<after> the actual backend has been detected	946	The block will be executed I<after> the actual backend has been detected
873	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been	947	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
874	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do	948	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
875	other initialisations - see the sources of L<AnyEvent::Strict> or	949	other initialisations - see the sources of L<AnyEvent::Strict> or
…		…
879	event module detection too early, for example, L<AnyEvent::AIO> creates	953	event module detection too early, for example, L<AnyEvent::AIO> creates
880	and installs the global L<IO::AIO> watcher in a C<post_detect> block to	954	and installs the global L<IO::AIO> watcher in a C<post_detect> block to
881	avoid autodetecting the event module at load time.	955	avoid autodetecting the event module at load time.
882		956
883	If called in scalar or list context, then it creates and returns an object	957	If called in scalar or list context, then it creates and returns an object
884	that automatically removes the callback again when it is destroyed. See	958	that automatically removes the callback again when it is destroyed (or
		959	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
885	L<Coro::BDB> for a case where this is useful.	960	a case where this is useful.
		961
		962	Example: Create a watcher for the IO::AIO module and store it in
		963	C<$WATCHER>, but do so only do so after the event loop is initialised.
		964
		965	our WATCHER;
		966
		967	my $guard = AnyEvent::post_detect {
		968	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
		969	};
		970
		971	# the ||= is important in case post_detect immediately runs the block,
		972	# as to not clobber the newly-created watcher. assigning both watcher and
		973	# post_detect guard to the same variable has the advantage of users being
		974	# able to just C<undef $WATCHER> if the watcher causes them grief.
		975
		976	$WATCHER ||= $guard;
886		977
887	=item @AnyEvent::post_detect	978	=item @AnyEvent::post_detect
888		979
889	If there are any code references in this array (you can C<push> to it	980	If there are any code references in this array (you can C<push> to it
890	before or after loading AnyEvent), then they will called directly after	981	before or after loading AnyEvent), then they will be called directly
891	the event loop has been chosen.	982	after the event loop has been chosen.
892		983
893	You should check C<$AnyEvent::MODEL> before adding to this array, though:	984	You should check C<$AnyEvent::MODEL> before adding to this array, though:
894	if it is defined then the event loop has already been detected, and the	985	if it is defined then the event loop has already been detected, and the
895	array will be ignored.	986	array will be ignored.
896		987
897	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows	988	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
898	it,as it takes care of these details.	989	it, as it takes care of these details.
899		990
900	This variable is mainly useful for modules that can do something useful	991	This variable is mainly useful for modules that can do something useful
901	when AnyEvent is used and thus want to know when it is initialised, but do	992	when AnyEvent is used and thus want to know when it is initialised, but do
902	not need to even load it by default. This array provides the means to hook	993	not need to even load it by default. This array provides the means to hook
903	into AnyEvent passively, without loading it.	994	into AnyEvent passively, without loading it.
904		995
		996	Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used
		997	together, you could put this into Coro (this is the actual code used by
		998	Coro to accomplish this):
		999
		1000	if (defined $AnyEvent::MODEL) {
		1001	# AnyEvent already initialised, so load Coro::AnyEvent
		1002	require Coro::AnyEvent;
		1003	} else {
		1004	# AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
		1005	# as soon as it is
		1006	push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
		1007	}
		1008
905	=back	1009	=back
906		1010
907	=head1 WHAT TO DO IN A MODULE	1011	=head1 WHAT TO DO IN A MODULE
908		1012
909	As a module author, you should C<use AnyEvent> and call AnyEvent methods	1013	As a module author, you should C<use AnyEvent> and call AnyEvent methods
…		…
919	because it will stall the whole program, and the whole point of using	1023	because it will stall the whole program, and the whole point of using
920	events is to stay interactive.	1024	events is to stay interactive.
921		1025
922	It is fine, however, to call C<< ->recv >> when the user of your module	1026	It is fine, however, to call C<< ->recv >> when the user of your module
923	requests it (i.e. if you create a http request object ad have a method	1027	requests it (i.e. if you create a http request object ad have a method
924	called C<results> that returns the results, it should call C<< ->recv >>	1028	called C<results> that returns the results, it may call C<< ->recv >>
925	freely, as the user of your module knows what she is doing. always).	1029	freely, as the user of your module knows what she is doing. Always).
926		1030
927	=head1 WHAT TO DO IN THE MAIN PROGRAM	1031	=head1 WHAT TO DO IN THE MAIN PROGRAM
928		1032
929	There will always be a single main program - the only place that should	1033	There will always be a single main program - the only place that should
930	dictate which event model to use.	1034	dictate which event model to use.
931		1035
932	If it doesn't care, it can just "use AnyEvent" and use it itself, or not	1036	If the program is not event-based, it need not do anything special, even
933	do anything special (it does not need to be event-based) and let AnyEvent	1037	when it depends on a module that uses an AnyEvent. If the program itself
934	decide which implementation to chose if some module relies on it.	1038	uses AnyEvent, but does not care which event loop is used, all it needs
		1039	to do is C<use AnyEvent>. In either case, AnyEvent will choose the best
		1040	available loop implementation.
935		1041
936	If the main program relies on a specific event model - for example, in	1042	If the main program relies on a specific event model - for example, in
937	Gtk2 programs you have to rely on the Glib module - you should load the	1043	Gtk2 programs you have to rely on the Glib module - you should load the
938	event module before loading AnyEvent or any module that uses it: generally	1044	event module before loading AnyEvent or any module that uses it: generally
939	speaking, you should load it as early as possible. The reason is that	1045	speaking, you should load it as early as possible. The reason is that
940	modules might create watchers when they are loaded, and AnyEvent will	1046	modules might create watchers when they are loaded, and AnyEvent will
941	decide on the event model to use as soon as it creates watchers, and it	1047	decide on the event model to use as soon as it creates watchers, and it
942	might chose the wrong one unless you load the correct one yourself.	1048	might choose the wrong one unless you load the correct one yourself.
943		1049
944	You can chose to use a pure-perl implementation by loading the	1050	You can chose to use a pure-perl implementation by loading the
945	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour	1051	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour
946	everywhere, but letting AnyEvent chose the model is generally better.	1052	everywhere, but letting AnyEvent chose the model is generally better.
947		1053
…		…
965	=head1 OTHER MODULES	1071	=head1 OTHER MODULES
966		1072
967	The following is a non-exhaustive list of additional modules that use	1073	The following is a non-exhaustive list of additional modules that use
968	AnyEvent as a client and can therefore be mixed easily with other AnyEvent	1074	AnyEvent as a client and can therefore be mixed easily with other AnyEvent
969	modules and other event loops in the same program. Some of the modules	1075	modules and other event loops in the same program. Some of the modules
970	come with AnyEvent, most are available via CPAN.	1076	come as part of AnyEvent, the others are available via CPAN.
971		1077
972	=over 4	1078	=over 4
973		1079
974	=item L<AnyEvent::Util>	1080	=item L<AnyEvent::Util>
975		1081
976	Contains various utility functions that replace often-used but blocking	1082	Contains various utility functions that replace often-used blocking
977	functions such as C<inet_aton> by event-/callback-based versions.	1083	functions such as C<inet_aton> with event/callback-based versions.
978		1084
979	=item L<AnyEvent::Socket>	1085	=item L<AnyEvent::Socket>
980		1086
981	Provides various utility functions for (internet protocol) sockets,	1087	Provides various utility functions for (internet protocol) sockets,
982	addresses and name resolution. Also functions to create non-blocking tcp	1088	addresses and name resolution. Also functions to create non-blocking tcp
…		…
984		1090
985	=item L<AnyEvent::Handle>	1091	=item L<AnyEvent::Handle>
986		1092
987	Provide read and write buffers, manages watchers for reads and writes,	1093	Provide read and write buffers, manages watchers for reads and writes,
988	supports raw and formatted I/O, I/O queued and fully transparent and	1094	supports raw and formatted I/O, I/O queued and fully transparent and
989	non-blocking SSL/TLS (via L<AnyEvent::TLS>.	1095	non-blocking SSL/TLS (via L<AnyEvent::TLS>).
990		1096
991	=item L<AnyEvent::DNS>	1097	=item L<AnyEvent::DNS>
992		1098
993	Provides rich asynchronous DNS resolver capabilities.	1099	Provides rich asynchronous DNS resolver capabilities.
994		1100
		1101	=item L<AnyEvent::HTTP>, L<AnyEvent::IRC>, L<AnyEvent::XMPP>, L<AnyEvent::GPSD>, L<AnyEvent::IGS>, L<AnyEvent::FCP>
		1102
		1103	Implement event-based interfaces to the protocols of the same name (for
		1104	the curious, IGS is the International Go Server and FCP is the Freenet
		1105	Client Protocol).
		1106
		1107	=item L<AnyEvent::Handle::UDP>
		1108
		1109	Here be danger!
		1110
		1111	As Pauli would put it, "Not only is it not right, it's not even wrong!" -
		1112	there are so many things wrong with AnyEvent::Handle::UDP, most notably
		1113	its use of a stream-based API with a protocol that isn't streamable, that
		1114	the only way to improve it is to delete it.
		1115
		1116	It features data corruption (but typically only under load) and general
		1117	confusion. On top, the author is not only clueless about UDP but also
		1118	fact-resistant - some gems of his understanding: "connect doesn't work
		1119	with UDP", "UDP packets are not IP packets", "UDP only has datagrams, not
		1120	packets", "I don't need to implement proper error checking as UDP doesn't
		1121	support error checking" and so on - he doesn't even understand what's
		1122	wrong with his module when it is explained to him.
		1123
995	=item L<AnyEvent::HTTP>	1124	=item L<AnyEvent::DBI>
996		1125
997	A simple-to-use HTTP library that is capable of making a lot of concurrent	1126	Executes L<DBI> requests asynchronously in a proxy process for you,
998	HTTP requests.	1127	notifying you in an event-based way when the operation is finished.
		1128
		1129	=item L<AnyEvent::AIO>
		1130
		1131	Truly asynchronous (as opposed to non-blocking) I/O, should be in the
		1132	toolbox of every event programmer. AnyEvent::AIO transparently fuses
		1133	L<IO::AIO> and AnyEvent together, giving AnyEvent access to event-based
		1134	file I/O, and much more.
999		1135
1000	=item L<AnyEvent::HTTPD>	1136	=item L<AnyEvent::HTTPD>
1001		1137
1002	Provides a simple web application server framework.	1138	A simple embedded webserver.
1003		1139
1004	=item L<AnyEvent::FastPing>	1140	=item L<AnyEvent::FastPing>
1005		1141
1006	The fastest ping in the west.	1142	The fastest ping in the west.
1007
1008	=item L<AnyEvent::DBI>
1009
1010	Executes L<DBI> requests asynchronously in a proxy process.
1011
1012	=item L<AnyEvent::AIO>
1013
1014	Truly asynchronous I/O, should be in the toolbox of every event
1015	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
1016	together.
1017
1018	=item L<AnyEvent::BDB>
1019
1020	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
1021	L<BDB> and AnyEvent together.
1022
1023	=item L<AnyEvent::GPSD>
1024
1025	A non-blocking interface to gpsd, a daemon delivering GPS information.
1026
1027	=item L<AnyEvent::IRC>
1028
1029	AnyEvent based IRC client module family (replacing the older Net::IRC3).
1030
1031	=item L<AnyEvent::XMPP>
1032
1033	AnyEvent based XMPP (Jabber protocol) module family (replacing the older
1034	Net::XMPP2>.
1035
1036	=item L<AnyEvent::IGS>
1037
1038	A non-blocking interface to the Internet Go Server protocol (used by
1039	L<App::IGS>).
1040
1041	=item L<Net::FCP>
1042
1043	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
1044	of AnyEvent.
1045
1046	=item L<Event::ExecFlow>
1047
1048	High level API for event-based execution flow control.
1049		1143
1050	=item L<Coro>	1144	=item L<Coro>
1051		1145
1052	Has special support for AnyEvent via L<Coro::AnyEvent>.	1146	Has special support for AnyEvent via L<Coro::AnyEvent>.
1053		1147
…		…
1057		1151
1058	package AnyEvent;	1152	package AnyEvent;
1059		1153
1060	# basically a tuned-down version of common::sense	1154	# basically a tuned-down version of common::sense
1061	sub common_sense {	1155	sub common_sense {
1062	# no warnings	1156	# from common:.sense 3.4
1063	${^WARNING_BITS} ^= ${^WARNING_BITS};	1157	${^WARNING_BITS} ^= ${^WARNING_BITS} ^ "\x3c\x3f\x33\x00\x0f\xf0\x0f\xc0\xf0\xfc\x33\x00";
1064	# use strict vars subs	1158	# use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)
1065	$^H |= 0x00000600;	1159	$^H |= 0x00000600;
1066	}	1160	}
1067		1161
1068	BEGIN { AnyEvent::common_sense }	1162	BEGIN { AnyEvent::common_sense }
1069		1163
1070	use Carp ();	1164	use Carp ();
1071		1165
1072	our $VERSION = 4.86;	1166	our $VERSION = '5.31';
1073	our $MODEL;	1167	our $MODEL;
1074		1168
1075	our $AUTOLOAD;	1169	our $AUTOLOAD;
1076	our @ISA;	1170	our @ISA;
1077		1171
1078	our @REGISTRY;	1172	our @REGISTRY;
1079		1173
1080	our $WIN32;
1081
1082	our $VERBOSE;	1174	our $VERBOSE;
1083		1175
1084	BEGIN {	1176	BEGIN {
1085	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";	1177	require "AnyEvent/constants.pl";
		1178
1086	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";	1179	eval "sub TAINT (){" . (${^TAINT}*1) . "}";
1087		1180
1088	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}	1181	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
1089	if ${^TAINT};	1182	if ${^TAINT};
1090		1183
1091	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1184	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
…		…
1102	for reverse split /\s*,\s*/,	1195	for reverse split /\s*,\s*/,
1103	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1196	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
1104	}	1197	}
1105		1198
1106	my @models = (	1199	my @models = (
1107	[EV:: => AnyEvent::Impl::EV::],	1200	[EV:: => AnyEvent::Impl::EV:: , 1],
1108	[Event:: => AnyEvent::Impl::Event::],
1109	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	1201	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],
1110	# everything below here will not be autoprobed	1202	# everything below here will not (normally) be autoprobed
1111	# as the pureperl backend should work everywhere	1203	# as the pureperl backend should work everywhere
1112	# and is usually faster	1204	# and is usually faster
		1205	[Event:: => AnyEvent::Impl::Event::, 1],
1113	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers	1206	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
1114	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	1207	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
		1208	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
1115	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1209	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
1116	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1210	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
1117	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1211	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
1118	[Wx:: => AnyEvent::Impl::POE::],	1212	[Wx:: => AnyEvent::Impl::POE::],
1119	[Prima:: => AnyEvent::Impl::POE::],	1213	[Prima:: => AnyEvent::Impl::POE::],
1120	# IO::Async is just too broken - we would need workarounds for its
1121	# byzantine signal and broken child handling, among others.
1122	# IO::Async is rather hard to detect, as it doesn't have any
1123	# obvious default class.
1124	# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
1125	# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program	1214	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::],
1126	# [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program	1215	[Cocoa::EventLoop:: => AnyEvent::Impl::Cocoa::],
1127	);	1216	);
1128		1217
1129	our %method = map +($_ => 1),	1218	our %method = map +($_ => 1),
1130	qw(io timer time now now_update signal child idle condvar one_event DESTROY);	1219	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
1131		1220
1132	our @post_detect;	1221	our @post_detect;
1133		1222
1134	sub post_detect(&) {	1223	sub post_detect(&) {
1135	my ($cb) = @_;	1224	my ($cb) = @_;
1136		1225
1137	if ($MODEL) {
1138	$cb->();
1139
1140	1
1141	} else {
1142	push @post_detect, $cb;	1226	push @post_detect, $cb;
1143		1227
1144	defined wantarray	1228	defined wantarray
1145	? bless \$cb, "AnyEvent::Util::postdetect"	1229	? bless \$cb, "AnyEvent::Util::postdetect"
1146	: ()	1230	: ()
1147	}
1148	}	1231	}
1149		1232
1150	sub AnyEvent::Util::postdetect::DESTROY {	1233	sub AnyEvent::Util::postdetect::DESTROY {
1151	@post_detect = grep $_ != ${$_[0]}, @post_detect;	1234	@post_detect = grep $_ != ${$_[0]}, @post_detect;
1152	}	1235	}
1153		1236
1154	sub detect() {	1237	sub detect() {
		1238	# free some memory
		1239	*detect = sub () { $MODEL };
		1240
		1241	local $!; # for good measure
		1242	local $SIG{__DIE__};
		1243
		1244	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
		1245	my $model = "AnyEvent::Impl::$1";
		1246	if (eval "require $model") {
		1247	$MODEL = $model;
		1248	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
		1249	} else {
		1250	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
		1251	}
		1252	}
		1253
		1254	# check for already loaded models
1155	unless ($MODEL) {	1255	unless ($MODEL) {
1156	local $SIG{__DIE__};	1256	for (@REGISTRY, @models) {
1157		1257	my ($package, $model) = @$_;
1158	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	1258	if (${"$package\::VERSION"} > 0) {
1159	my $model = "AnyEvent::Impl::$1";
1160	if (eval "require $model") {	1259	if (eval "require $model") {
1161	$MODEL = $model;	1260	$MODEL = $model;
1162	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;	1261	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1163	} else {	1262	last;
1164	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;	1263	}
1165	}	1264	}
1166	}	1265	}
1167		1266
1168	# check for already loaded models
1169	unless ($MODEL) {	1267	unless ($MODEL) {
		1268	# try to autoload a model
1170	for (@REGISTRY, @models) {	1269	for (@REGISTRY, @models) {
1171	my ($package, $model) = @$_;	1270	my ($package, $model, $autoload) = @$_;
		1271	if (
		1272	$autoload
		1273	and eval "require $package"
1172	if (${"$package\::VERSION"} > 0) {	1274	and ${"$package\::VERSION"} > 0
1173	if (eval "require $model") {	1275	and eval "require $model"
		1276	) {
1174	$MODEL = $model;	1277	$MODEL = $model;
1175	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;	1278	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
1176	last;	1279	last;
1177	}
1178	}	1280	}
1179	}	1281	}
1180		1282
1181	unless ($MODEL) {
1182	# try to load a model
1183
1184	for (@REGISTRY, @models) {
1185	my ($package, $model) = @$_;
1186	if (eval "require $package"
1187	and ${"$package\::VERSION"} > 0
1188	and eval "require $model") {
1189	$MODEL = $model;
1190	warn "AnyEvent: autoprobed model '$model', using it.\n" if $VERBOSE >= 2;
1191	last;
1192	}
1193	}
1194
1195	$MODEL	1283	$MODEL
1196	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";	1284	or die "AnyEvent: backend autodetection failed - did you properly install AnyEvent?\n";
1197	}
1198	}	1285	}
1199
1200	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1201
1202	unshift @ISA, $MODEL;
1203
1204	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
1205
1206	(shift @post_detect)->() while @post_detect;
1207	}	1286	}
		1287
		1288	@models = (); # free probe data
		1289
		1290	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1291	unshift @ISA, $MODEL;
		1292
		1293	# now nuke some methods that are overridden by the backend.
		1294	# SUPER is not allowed.
		1295	for (qw(time signal child idle)) {
		1296	undef &{"AnyEvent::Base::$_"}
		1297	if defined &{"$MODEL\::$_"};
		1298	}
		1299
		1300	if ($ENV{PERL_ANYEVENT_STRICT}) {
		1301	eval { require AnyEvent::Strict };
		1302	warn "AnyEvent: cannot load AnyEvent::Strict: $@"
		1303	if $@ && $VERBOSE;
		1304	}
		1305
		1306	(shift @post_detect)->() while @post_detect;
		1307
		1308	*post_detect = sub(&) {
		1309	shift->();
		1310
		1311	undef
		1312	};
1208		1313
1209	$MODEL	1314	$MODEL
1210	}	1315	}
1211		1316
1212	sub AUTOLOAD {	1317	sub AUTOLOAD {
1213	(my $func = $AUTOLOAD) =~ s/.*://;	1318	(my $func = $AUTOLOAD) =~ s/.*://;
1214		1319
1215	$method{$func}	1320	$method{$func}
1216	or Carp::croak "$func: not a valid method for AnyEvent objects";	1321	or Carp::croak "$func: not a valid AnyEvent class method";
1217		1322
1218	detect unless $MODEL;	1323	detect;
1219		1324
1220	my $class = shift;	1325	my $class = shift;
1221	$class->$func (@_);	1326	$class->$func (@_);
1222	}	1327	}
1223		1328
…		…
1236	# we assume CLOEXEC is already set by perl in all important cases	1341	# we assume CLOEXEC is already set by perl in all important cases
1237		1342
1238	($fh2, $rw)	1343	($fh2, $rw)
1239	}	1344	}
1240		1345
		1346	=head1 SIMPLIFIED AE API
		1347
		1348	Starting with version 5.0, AnyEvent officially supports a second, much
		1349	simpler, API that is designed to reduce the calling, typing and memory
		1350	overhead by using function call syntax and a fixed number of parameters.
		1351
		1352	See the L<AE> manpage for details.
		1353
		1354	=cut
		1355
		1356	package AE;
		1357
		1358	our $VERSION = $AnyEvent::VERSION;
		1359
		1360	# fall back to the main API by default - backends and AnyEvent::Base
		1361	# implementations can overwrite these.
		1362
		1363	sub io($$$) {
		1364	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
		1365	}
		1366
		1367	sub timer($$$) {
		1368	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
		1369	}
		1370
		1371	sub signal($$) {
		1372	AnyEvent->signal (signal => $_[0], cb => $_[1])
		1373	}
		1374
		1375	sub child($$) {
		1376	AnyEvent->child (pid => $_[0], cb => $_[1])
		1377	}
		1378
		1379	sub idle($) {
		1380	AnyEvent->idle (cb => $_[0])
		1381	}
		1382
		1383	sub cv(;&) {
		1384	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
		1385	}
		1386
		1387	sub now() {
		1388	AnyEvent->now
		1389	}
		1390
		1391	sub now_update() {
		1392	AnyEvent->now_update
		1393	}
		1394
		1395	sub time() {
		1396	AnyEvent->time
		1397	}
		1398
1241	package AnyEvent::Base;	1399	package AnyEvent::Base;
1242		1400
1243	# default implementations for many methods	1401	# default implementations for many methods
1244		1402
1245	sub _time {	1403	sub time {
		1404	eval q{ # poor man's autoloading {}
1246	# probe for availability of Time::HiRes	1405	# probe for availability of Time::HiRes
1247	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {	1406	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
1248	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;	1407	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1249	*_time = \&Time::HiRes::time;	1408	*AE::time = \&Time::HiRes::time;
1250	# if (eval "use POSIX (); (POSIX::times())...	1409	# if (eval "use POSIX (); (POSIX::times())...
1251	} else {	1410	} else {
1252	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;	1411	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1253	*_time = sub { time }; # epic fail	1412	*AE::time = sub (){ time }; # epic fail
		1413	}
		1414
		1415	*time = sub { AE::time }; # different prototypes
1254	}	1416	};
		1417	die if $@;
1255		1418
1256	&_time	1419	&time
1257	}	1420	}
1258		1421
1259	sub time { _time }	1422	*now = \&time;
1260	sub now { _time }	1423
1261	sub now_update { }	1424	sub now_update { }
1262		1425
1263	# default implementation for ->condvar	1426	# default implementation for ->condvar
1264		1427
1265	sub condvar {	1428	sub condvar {
		1429	eval q{ # poor man's autoloading {}
		1430	*condvar = sub {
1266	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"	1431	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
		1432	};
		1433
		1434	*AE::cv = sub (;&) {
		1435	bless { @_ ? (_ae_cb => shift) : () }, "AnyEvent::CondVar"
		1436	};
		1437	};
		1438	die if $@;
		1439
		1440	&condvar
1267	}	1441	}
1268		1442
1269	# default implementation for ->signal	1443	# default implementation for ->signal
1270		1444
1271	our $HAVE_ASYNC_INTERRUPT;	1445	our $HAVE_ASYNC_INTERRUPT;
		1446
		1447	sub _have_async_interrupt() {
		1448	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
		1449	&& eval "use Async::Interrupt 1.02 (); 1")
		1450	unless defined $HAVE_ASYNC_INTERRUPT;
		1451
		1452	$HAVE_ASYNC_INTERRUPT
		1453	}
		1454
1272	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1455	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
1273	our (%SIG_ASY, %SIG_ASY_W);	1456	our (%SIG_ASY, %SIG_ASY_W);
1274	our ($SIG_COUNT, $SIG_TW);	1457	our ($SIG_COUNT, $SIG_TW);
1275		1458
1276	sub _signal_exec {
1277	$HAVE_ASYNC_INTERRUPT
1278	? $SIGPIPE_R->drain
1279	: sysread $SIGPIPE_R, my $dummy, 9;
1280
1281	while (%SIG_EV) {
1282	for (keys %SIG_EV) {
1283	delete $SIG_EV{$_};
1284	$_->() for values %{ $SIG_CB{$_} || {} };
1285	}
1286	}
1287	}
1288
1289	# install a dumym wakeupw atcher to reduce signal catching latency	1459	# install a dummy wakeup watcher to reduce signal catching latency
		1460	# used by Impls
1290	sub _sig_add() {	1461	sub _sig_add() {
1291	unless ($SIG_COUNT++) {	1462	unless ($SIG_COUNT++) {
1292	# try to align timer on a full-second boundary, if possible	1463	# try to align timer on a full-second boundary, if possible
1293	my $NOW = AnyEvent->now;	1464	my $NOW = AE::now;
1294		1465
1295	$SIG_TW = AnyEvent->timer (	1466	$SIG_TW = AE::timer
1296	after => $MAX_SIGNAL_LATENCY - ($NOW - int $NOW),	1467	$MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
1297	interval => $MAX_SIGNAL_LATENCY,	1468	$MAX_SIGNAL_LATENCY,
1298	cb => sub { }, # just for the PERL_ASYNC_CHECK	1469	sub { } # just for the PERL_ASYNC_CHECK
1299	);	1470	;
1300	}	1471	}
1301	}	1472	}
1302		1473
1303	sub _sig_del {	1474	sub _sig_del {
1304	undef $SIG_TW	1475	undef $SIG_TW
1305	unless --$SIG_COUNT;	1476	unless --$SIG_COUNT;
1306	}	1477	}
1307		1478
		1479	our $_sig_name_init; $_sig_name_init = sub {
		1480	eval q{ # poor man's autoloading {}
		1481	undef $_sig_name_init;
		1482
		1483	if (_have_async_interrupt) {
		1484	*sig2num = \&Async::Interrupt::sig2num;
		1485	*sig2name = \&Async::Interrupt::sig2name;
		1486	} else {
		1487	require Config;
		1488
		1489	my %signame2num;
		1490	@signame2num{ split ' ', $Config::Config{sig_name} }
		1491	= split ' ', $Config::Config{sig_num};
		1492
		1493	my @signum2name;
		1494	@signum2name[values %signame2num] = keys %signame2num;
		1495
		1496	*sig2num = sub($) {
		1497	$_[0] > 0 ? shift : $signame2num{+shift}
		1498	};
		1499	*sig2name = sub ($) {
		1500	$_[0] > 0 ? $signum2name[+shift] : shift
		1501	};
		1502	}
		1503	};
		1504	die if $@;
		1505	};
		1506
		1507	sub sig2num ($) { &$_sig_name_init; &sig2num }
		1508	sub sig2name($) { &$_sig_name_init; &sig2name }
		1509
1308	sub _signal {	1510	sub signal {
1309	my (undef, %arg) = @_;	1511	eval q{ # poor man's autoloading {}
		1512	# probe for availability of Async::Interrupt
		1513	if (_have_async_interrupt) {
		1514	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1310		1515
1311	my $signal = uc $arg{signal}	1516	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1312	or Carp::croak "required option 'signal' is missing";	1517	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1313		1518
1314	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1519	} else {
		1520	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
1315		1521
1316	if ($HAVE_ASYNC_INTERRUPT) {	1522	if (AnyEvent::WIN32) {
1317	# async::interrupt	1523	require AnyEvent::Util;
1318		1524
1319	$SIG_ASY{$signal} ||= do {	1525	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1320	my $asy = new Async::Interrupt	1526	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
1321	cb => sub { undef $SIG_EV{$signal} },	1527	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
1322	signal => $signal,	1528	} else {
1323	pipe => [$SIGPIPE_R->filenos],	1529	pipe $SIGPIPE_R, $SIGPIPE_W;
		1530	fcntl $SIGPIPE_R, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_R;
		1531	fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case
		1532
		1533	# not strictly required, as $^F is normally 2, but let's make sure...
		1534	fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
		1535	fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
1324	;	1536	}
1325	$asy->pipe_autodrain (0);
1326		1537
1327	$asy	1538	$SIGPIPE_R
		1539	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1540
		1541	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
		1542	}
		1543
		1544	*signal = $HAVE_ASYNC_INTERRUPT
		1545	? sub {
		1546	my (undef, %arg) = @_;
		1547
		1548	# async::interrupt
		1549	my $signal = sig2num $arg{signal};
		1550	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1551
		1552	$SIG_ASY{$signal} ||= new Async::Interrupt
		1553	cb => sub { undef $SIG_EV{$signal} },
		1554	signal => $signal,
		1555	pipe => [$SIGPIPE_R->filenos],
		1556	pipe_autodrain => 0,
		1557	;
		1558
		1559	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1560	}
		1561	: sub {
		1562	my (undef, %arg) = @_;
		1563
		1564	# pure perl
		1565	my $signal = sig2name $arg{signal};
		1566	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1567
		1568	$SIG{$signal} ||= sub {
		1569	local $!;
		1570	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
		1571	undef $SIG_EV{$signal};
		1572	};
		1573
		1574	# can't do signal processing without introducing races in pure perl,
		1575	# so limit the signal latency.
		1576	_sig_add;
		1577
		1578	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1579	}
		1580	;
		1581
		1582	*AnyEvent::Base::signal::DESTROY = sub {
		1583	my ($signal, $cb) = @{$_[0]};
		1584
		1585	_sig_del;
		1586
		1587	delete $SIG_CB{$signal}{$cb};
		1588
		1589	$HAVE_ASYNC_INTERRUPT
		1590	? delete $SIG_ASY{$signal}
		1591	: # delete doesn't work with older perls - they then
		1592	# print weird messages, or just unconditionally exit
		1593	# instead of getting the default action.
		1594	undef $SIG{$signal}
		1595	unless keys %{ $SIG_CB{$signal} };
1328	};	1596	};
1329		1597
1330	} else {	1598	*_signal_exec = sub {
1331	# pure perl	1599	$HAVE_ASYNC_INTERRUPT
		1600	? $SIGPIPE_R->drain
		1601	: sysread $SIGPIPE_R, (my $dummy), 9;
1332		1602
1333	$SIG{$signal} ||= sub {	1603	while (%SIG_EV) {
1334	local $!;	1604	for (keys %SIG_EV) {
1335	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;	1605	delete $SIG_EV{$_};
1336	undef $SIG_EV{$signal};	1606	$_->() for values %{ $SIG_CB{$_} || {} };
		1607	}
		1608	}
1337	};	1609	};
1338
1339	# can't do signal processing without introducing races in pure perl,
1340	# so limit the signal latency.
1341	_sig_add;
1342	}	1610	};
		1611	die if $@;
1343		1612
1344	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
1345	}
1346
1347	sub signal {
1348	# probe for availability of Async::Interrupt
1349	if (!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT} && eval "use Async::Interrupt 0.6 (); 1") {
1350	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1351
1352	$HAVE_ASYNC_INTERRUPT = 1;
1353	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1354	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R->fileno, poll => "r", cb => \&_signal_exec);
1355
1356	} else {
1357	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
1358
1359	require Fcntl;
1360
1361	if (AnyEvent::WIN32) {
1362	require AnyEvent::Util;
1363
1364	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1365	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1366	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1367	} else {
1368	pipe $SIGPIPE_R, $SIGPIPE_W;
1369	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
1370	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
1371
1372	# not strictly required, as $^F is normally 2, but let's make sure...
1373	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1374	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1375	}
1376
1377	$SIGPIPE_R
1378	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1379
1380	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1381	}
1382
1383	*signal = \&_signal;
1384	&signal	1613	&signal
1385	}
1386
1387	sub AnyEvent::Base::signal::DESTROY {
1388	my ($signal, $cb) = @{$_[0]};
1389
1390	_sig_del;
1391
1392	delete $SIG_CB{$signal}{$cb};
1393
1394	$HAVE_ASYNC_INTERRUPT
1395	? delete $SIG_ASY{$signal}
1396	: # delete doesn't work with older perls - they then
1397	# print weird messages, or just unconditionally exit
1398	# instead of getting the default action.
1399	undef $SIG{$signal}
1400	unless keys %{ $SIG_CB{$signal} };
1401	}	1614	}
1402		1615
1403	# default implementation for ->child	1616	# default implementation for ->child
1404		1617
1405	our %PID_CB;	1618	our %PID_CB;
1406	our $CHLD_W;	1619	our $CHLD_W;
1407	our $CHLD_DELAY_W;	1620	our $CHLD_DELAY_W;
1408	our $WNOHANG;
1409		1621
1410	sub _sigchld {	1622	# used by many Impl's
1411	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1623	sub _emit_childstatus($$) {
1412	$_->($pid, $?)	1624	my (undef, $rpid, $rstatus) = @_;
		1625
		1626	$_->($rpid, $rstatus)
1413	for values %{ $PID_CB{$pid} || {} },	1627	for values %{ $PID_CB{$rpid} || {} },
1414	values %{ $PID_CB{0} || {} };	1628	values %{ $PID_CB{0} || {} };
1415	}
1416	}	1629	}
1417		1630
1418	sub child {	1631	sub child {
		1632	eval q{ # poor man's autoloading {}
		1633	*_sigchld = sub {
		1634	my $pid;
		1635
		1636	AnyEvent->_emit_childstatus ($pid, $?)
		1637	while ($pid = waitpid -1, WNOHANG) > 0;
		1638	};
		1639
		1640	*child = sub {
1419	my (undef, %arg) = @_;	1641	my (undef, %arg) = @_;
1420		1642
1421	defined (my $pid = $arg{pid} + 0)	1643	defined (my $pid = $arg{pid} + 0)
1422	or Carp::croak "required option 'pid' is missing";	1644	or Carp::croak "required option 'pid' is missing";
1423		1645
1424	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1646	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1425		1647
1426	# WNOHANG is almost cetrainly 1 everywhere
1427	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
1428	? 1
1429	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1430
1431	unless ($CHLD_W) {	1648	unless ($CHLD_W) {
1432	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1649	$CHLD_W = AE::signal CHLD => \&_sigchld;
1433	# child could be a zombie already, so make at least one round	1650	# child could be a zombie already, so make at least one round
1434	&_sigchld;	1651	&_sigchld;
1435	}	1652	}
1436		1653
1437	bless [$pid, $arg{cb}], "AnyEvent::Base::child"	1654	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1438	}	1655	};
1439		1656
1440	sub AnyEvent::Base::child::DESTROY {	1657	*AnyEvent::Base::child::DESTROY = sub {
1441	my ($pid, $cb) = @{$_[0]};	1658	my ($pid, $cb) = @{$_[0]};
1442		1659
1443	delete $PID_CB{$pid}{$cb};	1660	delete $PID_CB{$pid}{$cb};
1444	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1661	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1445		1662
1446	undef $CHLD_W unless keys %PID_CB;	1663	undef $CHLD_W unless keys %PID_CB;
		1664	};
		1665	};
		1666	die if $@;
		1667
		1668	&child
1447	}	1669	}
1448		1670
1449	# idle emulation is done by simply using a timer, regardless	1671	# idle emulation is done by simply using a timer, regardless
1450	# of whether the process is idle or not, and not letting	1672	# of whether the process is idle or not, and not letting
1451	# the callback use more than 50% of the time.	1673	# the callback use more than 50% of the time.
1452	sub idle {	1674	sub idle {
		1675	eval q{ # poor man's autoloading {}
		1676	*idle = sub {
1453	my (undef, %arg) = @_;	1677	my (undef, %arg) = @_;
1454		1678
1455	my ($cb, $w, $rcb) = $arg{cb};	1679	my ($cb, $w, $rcb) = $arg{cb};
1456		1680
1457	$rcb = sub {	1681	$rcb = sub {
1458	if ($cb) {	1682	if ($cb) {
1459	$w = _time;	1683	$w = _time;
1460	&$cb;	1684	&$cb;
1461	$w = _time - $w;	1685	$w = _time - $w;
1462		1686
1463	# never use more then 50% of the time for the idle watcher,	1687	# never use more then 50% of the time for the idle watcher,
1464	# within some limits	1688	# within some limits
1465	$w = 0.0001 if $w < 0.0001;	1689	$w = 0.0001 if $w < 0.0001;
1466	$w = 5 if $w > 5;	1690	$w = 5 if $w > 5;
1467		1691
1468	$w = AnyEvent->timer (after => $w, cb => $rcb);	1692	$w = AE::timer $w, 0, $rcb;
1469	} else {	1693	} else {
1470	# clean up...	1694	# clean up...
1471	undef $w;	1695	undef $w;
1472	undef $rcb;	1696	undef $rcb;
		1697	}
		1698	};
		1699
		1700	$w = AE::timer 0.05, 0, $rcb;
		1701
		1702	bless \\$cb, "AnyEvent::Base::idle"
1473	}	1703	};
		1704
		1705	*AnyEvent::Base::idle::DESTROY = sub {
		1706	undef $${$_[0]};
		1707	};
1474	};	1708	};
		1709	die if $@;
1475		1710
1476	$w = AnyEvent->timer (after => 0.05, cb => $rcb);	1711	&idle
1477
1478	bless \\$cb, "AnyEvent::Base::idle"
1479	}
1480
1481	sub AnyEvent::Base::idle::DESTROY {
1482	undef $${$_[0]};
1483	}	1712	}
1484		1713
1485	package AnyEvent::CondVar;	1714	package AnyEvent::CondVar;
1486		1715
1487	our @ISA = AnyEvent::CondVar::Base::;	1716	our @ISA = AnyEvent::CondVar::Base::;
		1717
		1718	# only to be used for subclassing
		1719	sub new {
		1720	my $class = shift;
		1721	bless AnyEvent->condvar (@_), $class
		1722	}
1488		1723
1489	package AnyEvent::CondVar::Base;	1724	package AnyEvent::CondVar::Base;
1490		1725
1491	#use overload	1726	#use overload
1492	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1727	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
…		…
1535	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1770	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
1536	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1771	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
1537	}	1772	}
1538		1773
1539	sub cb {	1774	sub cb {
1540	$_[0]{_ae_cb} = $_[1] if @_ > 1;	1775	my $cv = shift;
		1776
		1777	@_
		1778	and $cv->{_ae_cb} = shift
		1779	and $cv->{_ae_sent}
		1780	and (delete $cv->{_ae_cb})->($cv);
		1781
1541	$_[0]{_ae_cb}	1782	$cv->{_ae_cb}
1542	}	1783	}
1543		1784
1544	sub begin {	1785	sub begin {
1545	++$_[0]{_ae_counter};	1786	++$_[0]{_ae_counter};
1546	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;	1787	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
…		…
1608	check the arguments passed to most method calls. If it finds any problems,	1849	check the arguments passed to most method calls. If it finds any problems,
1609	it will croak.	1850	it will croak.
1610		1851
1611	In other words, enables "strict" mode.	1852	In other words, enables "strict" mode.
1612		1853
1613	Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>	1854	Unlike C<use strict> (or its modern cousin, C<< use L<common::sense>
1614	>>, it is definitely recommended to keep it off in production. Keeping	1855	>>, it is definitely recommended to keep it off in production. Keeping
1615	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs	1856	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
1616	can be very useful, however.	1857	can be very useful, however.
1617		1858
1618	=item C<PERL_ANYEVENT_MODEL>	1859	=item C<PERL_ANYEVENT_MODEL>
…		…
1755	warn "read: $input\n"; # output what has been read	1996	warn "read: $input\n"; # output what has been read
1756	$cv->send if $input =~ /^q/i; # quit program if /^q/i	1997	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1757	},	1998	},
1758	);	1999	);
1759		2000
1760	my $time_watcher; # can only be used once
1761
1762	sub new_timer {
1763	$timer = AnyEvent->timer (after => 1, cb => sub {	2001	my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1764	warn "timeout\n"; # print 'timeout' about every second	2002	warn "timeout\n"; # print 'timeout' at most every second
1765	&new_timer; # and restart the time
1766	});	2003	});
1767	}
1768
1769	new_timer; # create first timer
1770		2004
1771	$cv->recv; # wait until user enters /^q/i	2005	$cv->recv; # wait until user enters /^q/i
1772		2006
1773	=head1 REAL-WORLD EXAMPLE	2007	=head1 REAL-WORLD EXAMPLE
1774		2008
…		…
1847		2081
1848	The actual code goes further and collects all errors (C<die>s, exceptions)	2082	The actual code goes further and collects all errors (C<die>s, exceptions)
1849	that occurred during request processing. The C<result> method detects	2083	that occurred during request processing. The C<result> method detects
1850	whether an exception as thrown (it is stored inside the $txn object)	2084	whether an exception as thrown (it is stored inside the $txn object)
1851	and just throws the exception, which means connection errors and other	2085	and just throws the exception, which means connection errors and other
1852	problems get reported tot he code that tries to use the result, not in a	2086	problems get reported to the code that tries to use the result, not in a
1853	random callback.	2087	random callback.
1854		2088
1855	All of this enables the following usage styles:	2089	All of this enables the following usage styles:
1856		2090
1857	1. Blocking:	2091	1. Blocking:
…		…
1905	through AnyEvent. The benchmark creates a lot of timers (with a zero	2139	through AnyEvent. The benchmark creates a lot of timers (with a zero
1906	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	2140	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1907	which it is), lets them fire exactly once and destroys them again.	2141	which it is), lets them fire exactly once and destroys them again.
1908		2142
1909	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	2143	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1910	distribution.	2144	distribution. It uses the L<AE> interface, which makes a real difference
		2145	for the EV and Perl backends only.
1911		2146
1912	=head3 Explanation of the columns	2147	=head3 Explanation of the columns
1913		2148
1914	I<watcher> is the number of event watchers created/destroyed. Since	2149	I<watcher> is the number of event watchers created/destroyed. Since
1915	different event models feature vastly different performances, each event	2150	different event models feature vastly different performances, each event
…		…
1936	watcher.	2171	watcher.
1937		2172
1938	=head3 Results	2173	=head3 Results
1939		2174
1940	name watchers bytes create invoke destroy comment	2175	name watchers bytes create invoke destroy comment
1941	EV/EV 400000 224 0.47 0.35 0.27 EV native interface	2176	EV/EV 100000 223 0.47 0.43 0.27 EV native interface
1942	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	2177	EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
1943	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal	2178	Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
1944	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation	2179	Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
1945	Event/Event 16000 517 32.20 31.80 0.81 Event native interface	2180	Event/Event 16000 516 31.16 31.84 0.82 Event native interface
1946	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers	2181	Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
1947	IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll	2182	IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
1948	IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll	2183	IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
1949	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour	2184	Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
1950	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers	2185	Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
1951	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event	2186	POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
1952	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select	2187	POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
1953		2188
1954	=head3 Discussion	2189	=head3 Discussion
1955		2190
1956	The benchmark does I<not> measure scalability of the event loop very	2191	The benchmark does I<not> measure scalability of the event loop very
1957	well. For example, a select-based event loop (such as the pure perl one)	2192	well. For example, a select-based event loop (such as the pure perl one)
…		…
1969	benchmark machine, handling an event takes roughly 1600 CPU cycles with	2204	benchmark machine, handling an event takes roughly 1600 CPU cycles with
1970	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU	2205	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
1971	cycles with POE.	2206	cycles with POE.
1972		2207
1973	C<EV> is the sole leader regarding speed and memory use, which are both	2208	C<EV> is the sole leader regarding speed and memory use, which are both
1974	maximal/minimal, respectively. Even when going through AnyEvent, it uses	2209	maximal/minimal, respectively. When using the L<AE> API there is zero
		2210	overhead (when going through the AnyEvent API create is about 5-6 times
		2211	slower, with other times being equal, so still uses far less memory than
1975	far less memory than any other event loop and is still faster than Event	2212	any other event loop and is still faster than Event natively).
1976	natively.
1977		2213
1978	The pure perl implementation is hit in a few sweet spots (both the	2214	The pure perl implementation is hit in a few sweet spots (both the
1979	constant timeout and the use of a single fd hit optimisations in the perl	2215	constant timeout and the use of a single fd hit optimisations in the perl
1980	interpreter and the backend itself). Nevertheless this shows that it	2216	interpreter and the backend itself). Nevertheless this shows that it
1981	adds very little overhead in itself. Like any select-based backend its	2217	adds very little overhead in itself. Like any select-based backend its
…		…
2055	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100	2291	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
2056	(1%) are active. This mirrors the activity of large servers with many	2292	(1%) are active. This mirrors the activity of large servers with many
2057	connections, most of which are idle at any one point in time.	2293	connections, most of which are idle at any one point in time.
2058		2294
2059	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	2295	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
2060	distribution.	2296	distribution. It uses the L<AE> interface, which makes a real difference
		2297	for the EV and Perl backends only.
2061		2298
2062	=head3 Explanation of the columns	2299	=head3 Explanation of the columns
2063		2300
2064	I<sockets> is the number of sockets, and twice the number of "servers" (as	2301	I<sockets> is the number of sockets, and twice the number of "servers" (as
2065	each server has a read and write socket end).	2302	each server has a read and write socket end).
…		…
2073	a new one that moves the timeout into the future.	2310	a new one that moves the timeout into the future.
2074		2311
2075	=head3 Results	2312	=head3 Results
2076		2313
2077	name sockets create request	2314	name sockets create request
2078	EV 20000 69.01 11.16	2315	EV 20000 62.66 7.99
2079	Perl 20000 73.32 35.87	2316	Perl 20000 68.32 32.64
2080	IOAsync 20000 157.00 98.14 epoll	2317	IOAsync 20000 174.06 101.15 epoll
2081	IOAsync 20000 159.31 616.06 poll	2318	IOAsync 20000 174.67 610.84 poll
2082	Event 20000 212.62 257.32	2319	Event 20000 202.69 242.91
2083	Glib 20000 651.16 1896.30	2320	Glib 20000 557.01 1689.52
2084	POE 20000 349.67 12317.24 uses POE::Loop::Event	2321	POE 20000 341.54 12086.32 uses POE::Loop::Event
2085		2322
2086	=head3 Discussion	2323	=head3 Discussion
2087		2324
2088	This benchmark I<does> measure scalability and overall performance of the	2325	This benchmark I<does> measure scalability and overall performance of the
2089	particular event loop.	2326	particular event loop.
…		…
2215	As you can see, the AnyEvent + EV combination even beats the	2452	As you can see, the AnyEvent + EV combination even beats the
2216	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl	2453	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
2217	backend easily beats IO::Lambda and POE.	2454	backend easily beats IO::Lambda and POE.
2218		2455
2219	And even the 100% non-blocking version written using the high-level (and	2456	And even the 100% non-blocking version written using the high-level (and
2220	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a	2457	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
2221	large margin, even though it does all of DNS, tcp-connect and socket I/O	2458	higher level ("unoptimised") abstractions by a large margin, even though
2222	in a non-blocking way.	2459	it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
2223		2460
2224	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and	2461	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
2225	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are	2462	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
2226	part of the IO::lambda distribution and were used without any changes.	2463	part of the IO::Lambda distribution and were used without any changes.
2227		2464
2228		2465
2229	=head1 SIGNALS	2466	=head1 SIGNALS
2230		2467
2231	AnyEvent currently installs handlers for these signals:	2468	AnyEvent currently installs handlers for these signals:
…		…
2268	unless defined $SIG{PIPE};	2505	unless defined $SIG{PIPE};
2269		2506
2270	=head1 RECOMMENDED/OPTIONAL MODULES	2507	=head1 RECOMMENDED/OPTIONAL MODULES
2271		2508
2272	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and	2509	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
2273	it's built-in modules) are required to use it.	2510	its built-in modules) are required to use it.
2274		2511
2275	That does not mean that AnyEvent won't take advantage of some additional	2512	That does not mean that AnyEvent won't take advantage of some additional
2276	modules if they are installed.	2513	modules if they are installed.
2277		2514
2278	This section epxlains which additional modules will be used, and how they	2515	This section explains which additional modules will be used, and how they
2279	affect AnyEvent's operetion.	2516	affect AnyEvent's operation.
2280		2517
2281	=over 4	2518	=over 4
2282		2519
2283	=item L<Async::Interrupt>	2520	=item L<Async::Interrupt>
2284		2521
…		…
2289	catch the signals) with some delay (default is 10 seconds, look for	2526	catch the signals) with some delay (default is 10 seconds, look for
2290	C<$AnyEvent::MAX_SIGNAL_LATENCY>).	2527	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
2291		2528
2292	If this module is available, then it will be used to implement signal	2529	If this module is available, then it will be used to implement signal
2293	catching, which means that signals will not be delayed, and the event loop	2530	catching, which means that signals will not be delayed, and the event loop
2294	will not be interrupted regularly, which is more efficient (And good for	2531	will not be interrupted regularly, which is more efficient (and good for
2295	battery life on laptops).	2532	battery life on laptops).
2296		2533
2297	This affects not just the pure-perl event loop, but also other event loops	2534	This affects not just the pure-perl event loop, but also other event loops
2298	that have no signal handling on their own (e.g. Glib, Tk, Qt).	2535	that have no signal handling on their own (e.g. Glib, Tk, Qt).
2299		2536
…		…
2311	automatic timer adjustments even when no monotonic clock is available,	2548	automatic timer adjustments even when no monotonic clock is available,
2312	can take avdantage of advanced kernel interfaces such as C<epoll> and	2549	can take avdantage of advanced kernel interfaces such as C<epoll> and
2313	C<kqueue>, and is the fastest backend I<by far>. You can even embed	2550	C<kqueue>, and is the fastest backend I<by far>. You can even embed
2314	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).	2551	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
2315		2552
		2553	If you only use backends that rely on another event loop (e.g. C<Tk>),
		2554	then this module will do nothing for you.
		2555
2316	=item L<Guard>	2556	=item L<Guard>
2317		2557
2318	The guard module, when used, will be used to implement	2558	The guard module, when used, will be used to implement
2319	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a	2559	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
2320	lot less memory), but otherwise doesn't affect guard operation much. It is	2560	lot less memory), but otherwise doesn't affect guard operation much. It is
2321	purely used for performance.	2561	purely used for performance.
2322		2562
2323	=item L<JSON> and L<JSON::XS>	2563	=item L<JSON> and L<JSON::XS>
2324		2564
2325	This module is required when you want to read or write JSON data via	2565	One of these modules is required when you want to read or write JSON data
2326	L<AnyEvent::Handle>. It is also written in pure-perl, but can take	2566	via L<AnyEvent::Handle>. L<JSON> is also written in pure-perl, but can take
2327	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.	2567	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
2328
2329	In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
2330	installed.
2331		2568
2332	=item L<Net::SSLeay>	2569	=item L<Net::SSLeay>
2333		2570
2334	Implementing TLS/SSL in Perl is certainly interesting, but not very	2571	Implementing TLS/SSL in Perl is certainly interesting, but not very
2335	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with	2572	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
2336	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.	2573	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
2337		2574
2338	=item L<Time::HiRes>	2575	=item L<Time::HiRes>
2339		2576
2340	This module is part of perl since release 5.008. It will be used when the	2577	This module is part of perl since release 5.008. It will be used when the
2341	chosen event library does not come with a timing source on it's own. The	2578	chosen event library does not come with a timing source of its own. The
2342	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to	2579	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
2343	try to use a monotonic clock for timing stability.	2580	try to use a monotonic clock for timing stability.
2344		2581
2345	=back	2582	=back
2346		2583
2347		2584
2348	=head1 FORK	2585	=head1 FORK
2349		2586
2350	Most event libraries are not fork-safe. The ones who are usually are	2587	Most event libraries are not fork-safe. The ones who are usually are
2351	because they rely on inefficient but fork-safe C<select> or C<poll>	2588	because they rely on inefficient but fork-safe C<select> or C<poll> calls
2352	calls. Only L<EV> is fully fork-aware.	2589	- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
		2590	are usually badly thought-out hacks that are incompatible with fork in
		2591	one way or another. Only L<EV> is fully fork-aware and ensures that you
		2592	continue event-processing in both parent and child (or both, if you know
		2593	what you are doing).
		2594
		2595	This means that, in general, you cannot fork and do event processing in
		2596	the child if the event library was initialised before the fork (which
		2597	usually happens when the first AnyEvent watcher is created, or the library
		2598	is loaded).
2353		2599
2354	If you have to fork, you must either do so I<before> creating your first	2600	If you have to fork, you must either do so I<before> creating your first
2355	watcher OR you must not use AnyEvent at all in the child OR you must do	2601	watcher OR you must not use AnyEvent at all in the child OR you must do
2356	something completely out of the scope of AnyEvent.	2602	something completely out of the scope of AnyEvent.
		2603
		2604	The problem of doing event processing in the parent I<and> the child
		2605	is much more complicated: even for backends that I<are> fork-aware or
		2606	fork-safe, their behaviour is not usually what you want: fork clones all
		2607	watchers, that means all timers, I/O watchers etc. are active in both
		2608	parent and child, which is almost never what you want. USing C<exec>
		2609	to start worker children from some kind of manage rprocess is usually
		2610	preferred, because it is much easier and cleaner, at the expense of having
		2611	to have another binary.
2357		2612
2358		2613
2359	=head1 SECURITY CONSIDERATIONS	2614	=head1 SECURITY CONSIDERATIONS
2360		2615
2361	AnyEvent can be forced to load any event model via	2616	AnyEvent can be forced to load any event model via
…		…
2391	pronounced).	2646	pronounced).
2392		2647
2393		2648
2394	=head1 SEE ALSO	2649	=head1 SEE ALSO
2395		2650
		2651	Tutorial/Introduction: L<AnyEvent::Intro>.
		2652
		2653	FAQ: L<AnyEvent::FAQ>.
		2654
2396	Utility functions: L<AnyEvent::Util>.	2655	Utility functions: L<AnyEvent::Util>.
2397		2656
2398	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,	2657	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,
2399	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2658	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
2400		2659
2401	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2660	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
2402	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2661	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
2403	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2662	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
2404	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>.	2663	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.
2405		2664
2406	Non-blocking file handles, sockets, TCP clients and	2665	Non-blocking file handles, sockets, TCP clients and
2407	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.	2666	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2408		2667
2409	Asynchronous DNS: L<AnyEvent::DNS>.	2668	Asynchronous DNS: L<AnyEvent::DNS>.
2410		2669
2411	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,	2670	Thread support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>.
2412	L<Coro::Event>,
2413		2671
2414	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,	2672	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::IRC>,
2415	L<AnyEvent::HTTP>.	2673	L<AnyEvent::HTTP>.
2416		2674
2417		2675
2418	=head1 AUTHOR	2676	=head1 AUTHOR
2419		2677

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