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Revision 1.253 by root, Tue Jul 21 06:00:47 2009 UTC vs.
Revision 1.349 by root, Mon Jul 4 21:14:42 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.
		883	AnyEvent::Impl::FLTK based on FLTK.
801		884
802	=item Backends with special needs.	885	=item Backends with special needs.
803		886
804	Qt requires the Qt::Application to be instantiated first, but will	887	Qt requires the Qt::Application to be instantiated first, but will
805	otherwise be picked up automatically. As long as the main program	888	otherwise be picked up automatically. As long as the main program
806	instantiates the application before any AnyEvent watchers are created,	889	instantiates the application before any AnyEvent watchers are created,
807	everything should just work.	890	everything should just work.
808		891
809	AnyEvent::Impl::Qt based on Qt.	892	AnyEvent::Impl::Qt based on Qt.
810		893
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.	894	=item Event loops that are indirectly supported via other backends.
820		895
821	Some event loops can be supported via other modules:	896	Some event loops can be supported via other modules:
822		897
823	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.	898	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
…		…
848	Contains C<undef> until the first watcher is being created, before the	923	Contains C<undef> until the first watcher is being created, before the
849	backend has been autodetected.	924	backend has been autodetected.
850		925
851	Afterwards it contains the event model that is being used, which is the	926	Afterwards it contains the event model that is being used, which is the
852	name of the Perl class implementing the model. This class is usually one	927	name of the Perl class implementing the model. This class is usually one
853	of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the	928	of the C<AnyEvent::Impl::xxx> modules, but can be any other class in the
854	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it	929	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
855	will be C<urxvt::anyevent>).	930	will be C<urxvt::anyevent>).
856		931
857	=item AnyEvent::detect	932	=item AnyEvent::detect
858		933
859	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	934	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
860	if necessary. You should only call this function right before you would	935	if necessary. You should only call this function right before you would
861	have created an AnyEvent watcher anyway, that is, as late as possible at	936	have created an AnyEvent watcher anyway, that is, as late as possible at
862	runtime, and not e.g. while initialising of your module.	937	runtime, and not e.g. during initialisation of your module.
863		938
864	If you need to do some initialisation before AnyEvent watchers are	939	If you need to do some initialisation before AnyEvent watchers are
865	created, use C<post_detect>.	940	created, use C<post_detect>.
866		941
867	=item $guard = AnyEvent::post_detect { BLOCK }	942	=item $guard = AnyEvent::post_detect { BLOCK }
868		943
869	Arranges for the code block to be executed as soon as the event model is	944	Arranges for the code block to be executed as soon as the event model is
870	autodetected (or immediately if this has already happened).	945	autodetected (or immediately if that has already happened).
871		946
872	The block will be executed I<after> the actual backend has been detected	947	The block will be executed I<after> the actual backend has been detected
873	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been	948	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
874	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do	949	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
875	other initialisations - see the sources of L<AnyEvent::Strict> or	950	other initialisations - see the sources of L<AnyEvent::Strict> or
…		…
884	that automatically removes the callback again when it is destroyed (or	959	that automatically removes the callback again when it is destroyed (or
885	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for	960	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
886	a case where this is useful.	961	a case where this is useful.
887		962
888	Example: Create a watcher for the IO::AIO module and store it in	963	Example: Create a watcher for the IO::AIO module and store it in
889	C<$WATCHER>. Only do so after the event loop is initialised, though.	964	C<$WATCHER>, but do so only do so after the event loop is initialised.
890		965
891	our WATCHER;	966	our WATCHER;
892		967
893	my $guard = AnyEvent::post_detect {	968	my $guard = AnyEvent::post_detect {
894	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);	969	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
…		…
902	$WATCHER ||= $guard;	977	$WATCHER ||= $guard;
903		978
904	=item @AnyEvent::post_detect	979	=item @AnyEvent::post_detect
905		980
906	If there are any code references in this array (you can C<push> to it	981	If there are any code references in this array (you can C<push> to it
907	before or after loading AnyEvent), then they will called directly after	982	before or after loading AnyEvent), then they will be called directly
908	the event loop has been chosen.	983	after the event loop has been chosen.
909		984
910	You should check C<$AnyEvent::MODEL> before adding to this array, though:	985	You should check C<$AnyEvent::MODEL> before adding to this array, though:
911	if it is defined then the event loop has already been detected, and the	986	if it is defined then the event loop has already been detected, and the
912	array will be ignored.	987	array will be ignored.
913		988
914	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows	989	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
915	it,as it takes care of these details.	990	it, as it takes care of these details.
916		991
917	This variable is mainly useful for modules that can do something useful	992	This variable is mainly useful for modules that can do something useful
918	when AnyEvent is used and thus want to know when it is initialised, but do	993	when AnyEvent is used and thus want to know when it is initialised, but do
919	not need to even load it by default. This array provides the means to hook	994	not need to even load it by default. This array provides the means to hook
920	into AnyEvent passively, without loading it.	995	into AnyEvent passively, without loading it.
921		996
		997	Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used
		998	together, you could put this into Coro (this is the actual code used by
		999	Coro to accomplish this):
		1000
		1001	if (defined $AnyEvent::MODEL) {
		1002	# AnyEvent already initialised, so load Coro::AnyEvent
		1003	require Coro::AnyEvent;
		1004	} else {
		1005	# AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
		1006	# as soon as it is
		1007	push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
		1008	}
		1009
922	=back	1010	=back
923		1011
924	=head1 WHAT TO DO IN A MODULE	1012	=head1 WHAT TO DO IN A MODULE
925		1013
926	As a module author, you should C<use AnyEvent> and call AnyEvent methods	1014	As a module author, you should C<use AnyEvent> and call AnyEvent methods
…		…
936	because it will stall the whole program, and the whole point of using	1024	because it will stall the whole program, and the whole point of using
937	events is to stay interactive.	1025	events is to stay interactive.
938		1026
939	It is fine, however, to call C<< ->recv >> when the user of your module	1027	It is fine, however, to call C<< ->recv >> when the user of your module
940	requests it (i.e. if you create a http request object ad have a method	1028	requests it (i.e. if you create a http request object ad have a method
941	called C<results> that returns the results, it should call C<< ->recv >>	1029	called C<results> that returns the results, it may call C<< ->recv >>
942	freely, as the user of your module knows what she is doing. always).	1030	freely, as the user of your module knows what she is doing. Always).
943		1031
944	=head1 WHAT TO DO IN THE MAIN PROGRAM	1032	=head1 WHAT TO DO IN THE MAIN PROGRAM
945		1033
946	There will always be a single main program - the only place that should	1034	There will always be a single main program - the only place that should
947	dictate which event model to use.	1035	dictate which event model to use.
948		1036
949	If it doesn't care, it can just "use AnyEvent" and use it itself, or not	1037	If the program is not event-based, it need not do anything special, even
950	do anything special (it does not need to be event-based) and let AnyEvent	1038	when it depends on a module that uses an AnyEvent. If the program itself
951	decide which implementation to chose if some module relies on it.	1039	uses AnyEvent, but does not care which event loop is used, all it needs
		1040	to do is C<use AnyEvent>. In either case, AnyEvent will choose the best
		1041	available loop implementation.
952		1042
953	If the main program relies on a specific event model - for example, in	1043	If the main program relies on a specific event model - for example, in
954	Gtk2 programs you have to rely on the Glib module - you should load the	1044	Gtk2 programs you have to rely on the Glib module - you should load the
955	event module before loading AnyEvent or any module that uses it: generally	1045	event module before loading AnyEvent or any module that uses it: generally
956	speaking, you should load it as early as possible. The reason is that	1046	speaking, you should load it as early as possible. The reason is that
957	modules might create watchers when they are loaded, and AnyEvent will	1047	modules might create watchers when they are loaded, and AnyEvent will
958	decide on the event model to use as soon as it creates watchers, and it	1048	decide on the event model to use as soon as it creates watchers, and it
959	might chose the wrong one unless you load the correct one yourself.	1049	might choose the wrong one unless you load the correct one yourself.
960		1050
961	You can chose to use a pure-perl implementation by loading the	1051	You can chose to use a pure-perl implementation by loading the
962	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour	1052	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour
963	everywhere, but letting AnyEvent chose the model is generally better.	1053	everywhere, but letting AnyEvent chose the model is generally better.
964		1054
…		…
982	=head1 OTHER MODULES	1072	=head1 OTHER MODULES
983		1073
984	The following is a non-exhaustive list of additional modules that use	1074	The following is a non-exhaustive list of additional modules that use
985	AnyEvent as a client and can therefore be mixed easily with other AnyEvent	1075	AnyEvent as a client and can therefore be mixed easily with other AnyEvent
986	modules and other event loops in the same program. Some of the modules	1076	modules and other event loops in the same program. Some of the modules
987	come with AnyEvent, most are available via CPAN.	1077	come as part of AnyEvent, the others are available via CPAN.
988		1078
989	=over 4	1079	=over 4
990		1080
991	=item L<AnyEvent::Util>	1081	=item L<AnyEvent::Util>
992		1082
993	Contains various utility functions that replace often-used but blocking	1083	Contains various utility functions that replace often-used blocking
994	functions such as C<inet_aton> by event-/callback-based versions.	1084	functions such as C<inet_aton> with event/callback-based versions.
995		1085
996	=item L<AnyEvent::Socket>	1086	=item L<AnyEvent::Socket>
997		1087
998	Provides various utility functions for (internet protocol) sockets,	1088	Provides various utility functions for (internet protocol) sockets,
999	addresses and name resolution. Also functions to create non-blocking tcp	1089	addresses and name resolution. Also functions to create non-blocking tcp
…		…
1001		1091
1002	=item L<AnyEvent::Handle>	1092	=item L<AnyEvent::Handle>
1003		1093
1004	Provide read and write buffers, manages watchers for reads and writes,	1094	Provide read and write buffers, manages watchers for reads and writes,
1005	supports raw and formatted I/O, I/O queued and fully transparent and	1095	supports raw and formatted I/O, I/O queued and fully transparent and
1006	non-blocking SSL/TLS (via L<AnyEvent::TLS>.	1096	non-blocking SSL/TLS (via L<AnyEvent::TLS>).
1007		1097
1008	=item L<AnyEvent::DNS>	1098	=item L<AnyEvent::DNS>
1009		1099
1010	Provides rich asynchronous DNS resolver capabilities.	1100	Provides rich asynchronous DNS resolver capabilities.
1011		1101
		1102	=item L<AnyEvent::HTTP>, L<AnyEvent::IRC>, L<AnyEvent::XMPP>, L<AnyEvent::GPSD>, L<AnyEvent::IGS>, L<AnyEvent::FCP>
		1103
		1104	Implement event-based interfaces to the protocols of the same name (for
		1105	the curious, IGS is the International Go Server and FCP is the Freenet
		1106	Client Protocol).
		1107
		1108	=item L<AnyEvent::Handle::UDP>
		1109
		1110	Here be danger!
		1111
		1112	As Pauli would put it, "Not only is it not right, it's not even wrong!" -
		1113	there are so many things wrong with AnyEvent::Handle::UDP, most notably
		1114	its use of a stream-based API with a protocol that isn't streamable, that
		1115	the only way to improve it is to delete it.
		1116
		1117	It features data corruption (but typically only under load) and general
		1118	confusion. On top, the author is not only clueless about UDP but also
		1119	fact-resistant - some gems of his understanding: "connect doesn't work
		1120	with UDP", "UDP packets are not IP packets", "UDP only has datagrams, not
		1121	packets", "I don't need to implement proper error checking as UDP doesn't
		1122	support error checking" and so on - he doesn't even understand what's
		1123	wrong with his module when it is explained to him.
		1124
1012	=item L<AnyEvent::HTTP>	1125	=item L<AnyEvent::DBI>
1013		1126
1014	A simple-to-use HTTP library that is capable of making a lot of concurrent	1127	Executes L<DBI> requests asynchronously in a proxy process for you,
1015	HTTP requests.	1128	notifying you in an event-based way when the operation is finished.
		1129
		1130	=item L<AnyEvent::AIO>
		1131
		1132	Truly asynchronous (as opposed to non-blocking) I/O, should be in the
		1133	toolbox of every event programmer. AnyEvent::AIO transparently fuses
		1134	L<IO::AIO> and AnyEvent together, giving AnyEvent access to event-based
		1135	file I/O, and much more.
1016		1136
1017	=item L<AnyEvent::HTTPD>	1137	=item L<AnyEvent::HTTPD>
1018		1138
1019	Provides a simple web application server framework.	1139	A simple embedded webserver.
1020		1140
1021	=item L<AnyEvent::FastPing>	1141	=item L<AnyEvent::FastPing>
1022		1142
1023	The fastest ping in the west.	1143	The fastest ping in the west.
1024
1025	=item L<AnyEvent::DBI>
1026
1027	Executes L<DBI> requests asynchronously in a proxy process.
1028
1029	=item L<AnyEvent::AIO>
1030
1031	Truly asynchronous I/O, should be in the toolbox of every event
1032	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
1033	together.
1034
1035	=item L<AnyEvent::BDB>
1036
1037	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
1038	L<BDB> and AnyEvent together.
1039
1040	=item L<AnyEvent::GPSD>
1041
1042	A non-blocking interface to gpsd, a daemon delivering GPS information.
1043
1044	=item L<AnyEvent::IRC>
1045
1046	AnyEvent based IRC client module family (replacing the older Net::IRC3).
1047
1048	=item L<AnyEvent::XMPP>
1049
1050	AnyEvent based XMPP (Jabber protocol) module family (replacing the older
1051	Net::XMPP2>.
1052
1053	=item L<AnyEvent::IGS>
1054
1055	A non-blocking interface to the Internet Go Server protocol (used by
1056	L<App::IGS>).
1057
1058	=item L<Net::FCP>
1059
1060	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
1061	of AnyEvent.
1062
1063	=item L<Event::ExecFlow>
1064
1065	High level API for event-based execution flow control.
1066		1144
1067	=item L<Coro>	1145	=item L<Coro>
1068		1146
1069	Has special support for AnyEvent via L<Coro::AnyEvent>.	1147	Has special support for AnyEvent via L<Coro::AnyEvent>.
1070		1148
…		…
1074		1152
1075	package AnyEvent;	1153	package AnyEvent;
1076		1154
1077	# basically a tuned-down version of common::sense	1155	# basically a tuned-down version of common::sense
1078	sub common_sense {	1156	sub common_sense {
1079	# no warnings	1157	# from common:.sense 3.4
1080	${^WARNING_BITS} ^= ${^WARNING_BITS};	1158	${^WARNING_BITS} ^= ${^WARNING_BITS} ^ "\x3c\x3f\x33\x00\x0f\xf0\x0f\xc0\xf0\xfc\x33\x00";
1081	# use strict vars subs	1159	# use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)
1082	$^H |= 0x00000600;	1160	$^H |= 0x00000600;
1083	}	1161	}
1084		1162
1085	BEGIN { AnyEvent::common_sense }	1163	BEGIN { AnyEvent::common_sense }
1086		1164
1087	use Carp ();	1165	use Carp ();
1088		1166
1089	our $VERSION = 4.86;	1167	our $VERSION = '5.34';
1090	our $MODEL;	1168	our $MODEL;
1091		1169
1092	our $AUTOLOAD;	1170	our $AUTOLOAD;
1093	our @ISA;	1171	our @ISA;
1094		1172
1095	our @REGISTRY;	1173	our @REGISTRY;
1096		1174
1097	our $WIN32;
1098
1099	our $VERBOSE;	1175	our $VERBOSE;
1100		1176
1101	BEGIN {	1177	BEGIN {
1102	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";	1178	require "AnyEvent/constants.pl";
		1179
1103	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";	1180	eval "sub TAINT (){" . (${^TAINT}*1) . "}";
1104		1181
1105	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}	1182	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
1106	if ${^TAINT};	1183	if ${^TAINT};
1107		1184
1108	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1185	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
…		…
1119	for reverse split /\s*,\s*/,	1196	for reverse split /\s*,\s*/,
1120	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1197	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
1121	}	1198	}
1122		1199
1123	my @models = (	1200	my @models = (
1124	[EV:: => AnyEvent::Impl::EV::],	1201	[EV:: => AnyEvent::Impl::EV:: , 1],
1125	[Event:: => AnyEvent::Impl::Event::],
1126	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	1202	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],
1127	# everything below here will not be autoprobed	1203	# everything below here will not (normally) be autoprobed
1128	# as the pureperl backend should work everywhere	1204	# as the pureperl backend should work everywhere
1129	# and is usually faster	1205	# and is usually faster
		1206	[Event:: => AnyEvent::Impl::Event::, 1],
1130	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers	1207	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
1131	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	1208	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
		1209	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
1132	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1210	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
1133	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1211	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
1134	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1212	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
1135	[Wx:: => AnyEvent::Impl::POE::],	1213	[Wx:: => AnyEvent::Impl::POE::],
1136	[Prima:: => AnyEvent::Impl::POE::],	1214	[Prima:: => AnyEvent::Impl::POE::],
1137	# IO::Async is just too broken - we would need workarounds for its
1138	# byzantine signal and broken child handling, among others.
1139	# IO::Async is rather hard to detect, as it doesn't have any
1140	# obvious default class.
1141	# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
1142	# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program	1215	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::],
1143	# [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program	1216	[Cocoa::EventLoop:: => AnyEvent::Impl::Cocoa::],
		1217	[FLTK:: => AnyEvent::Impl::FLTK::],
1144	);	1218	);
1145		1219
1146	our %method = map +($_ => 1),	1220	our %method = map +($_ => 1),
1147	qw(io timer time now now_update signal child idle condvar one_event DESTROY);	1221	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
1148		1222
1149	our @post_detect;	1223	our @post_detect;
1150		1224
1151	sub post_detect(&) {	1225	sub post_detect(&) {
1152	my ($cb) = @_;	1226	my ($cb) = @_;
1153		1227
1154	if ($MODEL) {
1155	$cb->();
1156
1157	undef
1158	} else {
1159	push @post_detect, $cb;	1228	push @post_detect, $cb;
1160		1229
1161	defined wantarray	1230	defined wantarray
1162	? bless \$cb, "AnyEvent::Util::postdetect"	1231	? bless \$cb, "AnyEvent::Util::postdetect"
1163	: ()	1232	: ()
1164	}
1165	}	1233	}
1166		1234
1167	sub AnyEvent::Util::postdetect::DESTROY {	1235	sub AnyEvent::Util::postdetect::DESTROY {
1168	@post_detect = grep $_ != ${$_[0]}, @post_detect;	1236	@post_detect = grep $_ != ${$_[0]}, @post_detect;
1169	}	1237	}
1170		1238
1171	sub detect() {	1239	sub detect() {
		1240	# free some memory
		1241	*detect = sub () { $MODEL };
		1242
		1243	local $!; # for good measure
		1244	local $SIG{__DIE__};
		1245
		1246	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
		1247	my $model = "AnyEvent::Impl::$1";
		1248	if (eval "require $model") {
		1249	$MODEL = $model;
		1250	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
		1251	} else {
		1252	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
		1253	}
		1254	}
		1255
		1256	# check for already loaded models
1172	unless ($MODEL) {	1257	unless ($MODEL) {
1173	local $SIG{__DIE__};	1258	for (@REGISTRY, @models) {
1174		1259	my ($package, $model) = @$_;
1175	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	1260	if (${"$package\::VERSION"} > 0) {
1176	my $model = "AnyEvent::Impl::$1";
1177	if (eval "require $model") {	1261	if (eval "require $model") {
1178	$MODEL = $model;	1262	$MODEL = $model;
1179	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;	1263	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1180	} else {	1264	last;
1181	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;	1265	}
1182	}	1266	}
1183	}	1267	}
1184		1268
1185	# check for already loaded models
1186	unless ($MODEL) {	1269	unless ($MODEL) {
		1270	# try to autoload a model
1187	for (@REGISTRY, @models) {	1271	for (@REGISTRY, @models) {
1188	my ($package, $model) = @$_;	1272	my ($package, $model, $autoload) = @$_;
		1273	if (
		1274	$autoload
		1275	and eval "require $package"
1189	if (${"$package\::VERSION"} > 0) {	1276	and ${"$package\::VERSION"} > 0
1190	if (eval "require $model") {	1277	and eval "require $model"
		1278	) {
1191	$MODEL = $model;	1279	$MODEL = $model;
1192	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;	1280	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
1193	last;	1281	last;
1194	}
1195	}	1282	}
1196	}	1283	}
1197		1284
1198	unless ($MODEL) {
1199	# try to load a model
1200
1201	for (@REGISTRY, @models) {
1202	my ($package, $model) = @$_;
1203	if (eval "require $package"
1204	and ${"$package\::VERSION"} > 0
1205	and eval "require $model") {
1206	$MODEL = $model;
1207	warn "AnyEvent: autoprobed model '$model', using it.\n" if $VERBOSE >= 2;
1208	last;
1209	}
1210	}
1211
1212	$MODEL	1285	$MODEL
1213	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";	1286	or die "AnyEvent: backend autodetection failed - did you properly install AnyEvent?\n";
1214	}
1215	}	1287	}
1216
1217	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1218
1219	unshift @ISA, $MODEL;
1220
1221	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
1222
1223	(shift @post_detect)->() while @post_detect;
1224	}	1288	}
		1289
		1290	@models = (); # free probe data
		1291
		1292	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1293	unshift @ISA, $MODEL;
		1294
		1295	# now nuke some methods that are overridden by the backend.
		1296	# SUPER is not allowed.
		1297	for (qw(time signal child idle)) {
		1298	undef &{"AnyEvent::Base::$_"}
		1299	if defined &{"$MODEL\::$_"};
		1300	}
		1301
		1302	if ($ENV{PERL_ANYEVENT_STRICT}) {
		1303	eval { require AnyEvent::Strict };
		1304	warn "AnyEvent: cannot load AnyEvent::Strict: $@"
		1305	if $@ && $VERBOSE;
		1306	}
		1307
		1308	(shift @post_detect)->() while @post_detect;
		1309
		1310	*post_detect = sub(&) {
		1311	shift->();
		1312
		1313	undef
		1314	};
1225		1315
1226	$MODEL	1316	$MODEL
1227	}	1317	}
1228		1318
1229	sub AUTOLOAD {	1319	sub AUTOLOAD {
1230	(my $func = $AUTOLOAD) =~ s/.*://;	1320	(my $func = $AUTOLOAD) =~ s/.*://;
1231		1321
1232	$method{$func}	1322	$method{$func}
1233	or Carp::croak "$func: not a valid method for AnyEvent objects";	1323	or Carp::croak "$func: not a valid AnyEvent class method";
1234		1324
1235	detect unless $MODEL;	1325	detect;
1236		1326
1237	my $class = shift;	1327	my $class = shift;
1238	$class->$func (@_);	1328	$class->$func (@_);
1239	}	1329	}
1240		1330
…		…
1253	# we assume CLOEXEC is already set by perl in all important cases	1343	# we assume CLOEXEC is already set by perl in all important cases
1254		1344
1255	($fh2, $rw)	1345	($fh2, $rw)
1256	}	1346	}
1257		1347
		1348	=head1 SIMPLIFIED AE API
		1349
		1350	Starting with version 5.0, AnyEvent officially supports a second, much
		1351	simpler, API that is designed to reduce the calling, typing and memory
		1352	overhead by using function call syntax and a fixed number of parameters.
		1353
		1354	See the L<AE> manpage for details.
		1355
		1356	=cut
		1357
		1358	package AE;
		1359
		1360	our $VERSION = $AnyEvent::VERSION;
		1361
		1362	# fall back to the main API by default - backends and AnyEvent::Base
		1363	# implementations can overwrite these.
		1364
		1365	sub io($$$) {
		1366	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
		1367	}
		1368
		1369	sub timer($$$) {
		1370	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
		1371	}
		1372
		1373	sub signal($$) {
		1374	AnyEvent->signal (signal => $_[0], cb => $_[1])
		1375	}
		1376
		1377	sub child($$) {
		1378	AnyEvent->child (pid => $_[0], cb => $_[1])
		1379	}
		1380
		1381	sub idle($) {
		1382	AnyEvent->idle (cb => $_[0])
		1383	}
		1384
		1385	sub cv(;&) {
		1386	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
		1387	}
		1388
		1389	sub now() {
		1390	AnyEvent->now
		1391	}
		1392
		1393	sub now_update() {
		1394	AnyEvent->now_update
		1395	}
		1396
		1397	sub time() {
		1398	AnyEvent->time
		1399	}
		1400
1258	package AnyEvent::Base;	1401	package AnyEvent::Base;
1259		1402
1260	# default implementations for many methods	1403	# default implementations for many methods
1261		1404
1262	sub _time {	1405	sub time {
		1406	eval q{ # poor man's autoloading {}
1263	# probe for availability of Time::HiRes	1407	# probe for availability of Time::HiRes
1264	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {	1408	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
1265	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;	1409	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1266	*_time = \&Time::HiRes::time;	1410	*AE::time = \&Time::HiRes::time;
1267	# if (eval "use POSIX (); (POSIX::times())...	1411	# if (eval "use POSIX (); (POSIX::times())...
1268	} else {	1412	} else {
1269	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;	1413	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1270	*_time = sub { time }; # epic fail	1414	*AE::time = sub (){ time }; # epic fail
		1415	}
		1416
		1417	*time = sub { AE::time }; # different prototypes
1271	}	1418	};
		1419	die if $@;
1272		1420
1273	&_time	1421	&time
1274	}	1422	}
1275		1423
1276	sub time { _time }	1424	*now = \&time;
1277	sub now { _time }	1425
1278	sub now_update { }	1426	sub now_update { }
1279		1427
1280	# default implementation for ->condvar	1428	# default implementation for ->condvar
1281		1429
1282	sub condvar {	1430	sub condvar {
		1431	eval q{ # poor man's autoloading {}
		1432	*condvar = sub {
1283	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"	1433	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
		1434	};
		1435
		1436	*AE::cv = sub (;&) {
		1437	bless { @_ ? (_ae_cb => shift) : () }, "AnyEvent::CondVar"
		1438	};
		1439	};
		1440	die if $@;
		1441
		1442	&condvar
1284	}	1443	}
1285		1444
1286	# default implementation for ->signal	1445	# default implementation for ->signal
1287		1446
1288	our $HAVE_ASYNC_INTERRUPT;	1447	our $HAVE_ASYNC_INTERRUPT;
		1448
		1449	sub _have_async_interrupt() {
		1450	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
		1451	&& eval "use Async::Interrupt 1.02 (); 1")
		1452	unless defined $HAVE_ASYNC_INTERRUPT;
		1453
		1454	$HAVE_ASYNC_INTERRUPT
		1455	}
		1456
1289	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1457	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
1290	our (%SIG_ASY, %SIG_ASY_W);	1458	our (%SIG_ASY, %SIG_ASY_W);
1291	our ($SIG_COUNT, $SIG_TW);	1459	our ($SIG_COUNT, $SIG_TW);
1292		1460
1293	sub _signal_exec {
1294	$HAVE_ASYNC_INTERRUPT
1295	? $SIGPIPE_R->drain
1296	: sysread $SIGPIPE_R, my $dummy, 9;
1297
1298	while (%SIG_EV) {
1299	for (keys %SIG_EV) {
1300	delete $SIG_EV{$_};
1301	$_->() for values %{ $SIG_CB{$_} || {} };
1302	}
1303	}
1304	}
1305
1306	# install a dumym wakeupw atcher to reduce signal catching latency	1461	# install a dummy wakeup watcher to reduce signal catching latency
		1462	# used by Impls
1307	sub _sig_add() {	1463	sub _sig_add() {
1308	unless ($SIG_COUNT++) {	1464	unless ($SIG_COUNT++) {
1309	# try to align timer on a full-second boundary, if possible	1465	# try to align timer on a full-second boundary, if possible
1310	my $NOW = AnyEvent->now;	1466	my $NOW = AE::now;
1311		1467
1312	$SIG_TW = AnyEvent->timer (	1468	$SIG_TW = AE::timer
1313	after => $MAX_SIGNAL_LATENCY - ($NOW - int $NOW),	1469	$MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
1314	interval => $MAX_SIGNAL_LATENCY,	1470	$MAX_SIGNAL_LATENCY,
1315	cb => sub { }, # just for the PERL_ASYNC_CHECK	1471	sub { } # just for the PERL_ASYNC_CHECK
1316	);	1472	;
1317	}	1473	}
1318	}	1474	}
1319		1475
1320	sub _sig_del {	1476	sub _sig_del {
1321	undef $SIG_TW	1477	undef $SIG_TW
1322	unless --$SIG_COUNT;	1478	unless --$SIG_COUNT;
1323	}	1479	}
1324		1480
		1481	our $_sig_name_init; $_sig_name_init = sub {
		1482	eval q{ # poor man's autoloading {}
		1483	undef $_sig_name_init;
		1484
		1485	if (_have_async_interrupt) {
		1486	*sig2num = \&Async::Interrupt::sig2num;
		1487	*sig2name = \&Async::Interrupt::sig2name;
		1488	} else {
		1489	require Config;
		1490
		1491	my %signame2num;
		1492	@signame2num{ split ' ', $Config::Config{sig_name} }
		1493	= split ' ', $Config::Config{sig_num};
		1494
		1495	my @signum2name;
		1496	@signum2name[values %signame2num] = keys %signame2num;
		1497
		1498	*sig2num = sub($) {
		1499	$_[0] > 0 ? shift : $signame2num{+shift}
		1500	};
		1501	*sig2name = sub ($) {
		1502	$_[0] > 0 ? $signum2name[+shift] : shift
		1503	};
		1504	}
		1505	};
		1506	die if $@;
		1507	};
		1508
		1509	sub sig2num ($) { &$_sig_name_init; &sig2num }
		1510	sub sig2name($) { &$_sig_name_init; &sig2name }
		1511
1325	sub _signal {	1512	sub signal {
1326	my (undef, %arg) = @_;	1513	eval q{ # poor man's autoloading {}
		1514	# probe for availability of Async::Interrupt
		1515	if (_have_async_interrupt) {
		1516	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1327		1517
1328	my $signal = uc $arg{signal}	1518	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1329	or Carp::croak "required option 'signal' is missing";	1519	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1330		1520
1331	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1521	} else {
		1522	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
1332		1523
1333	if ($HAVE_ASYNC_INTERRUPT) {	1524	if (AnyEvent::WIN32) {
1334	# async::interrupt	1525	require AnyEvent::Util;
1335		1526
1336	$SIG_ASY{$signal} ||= do {	1527	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1337	my $asy = new Async::Interrupt	1528	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
1338	cb => sub { undef $SIG_EV{$signal} },	1529	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
1339	signal => $signal,	1530	} else {
1340	pipe => [$SIGPIPE_R->filenos],	1531	pipe $SIGPIPE_R, $SIGPIPE_W;
		1532	fcntl $SIGPIPE_R, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_R;
		1533	fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case
		1534
		1535	# not strictly required, as $^F is normally 2, but let's make sure...
		1536	fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
		1537	fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
1341	;	1538	}
1342	$asy->pipe_autodrain (0);
1343		1539
1344	$asy	1540	$SIGPIPE_R
		1541	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1542
		1543	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
		1544	}
		1545
		1546	*signal = $HAVE_ASYNC_INTERRUPT
		1547	? sub {
		1548	my (undef, %arg) = @_;
		1549
		1550	# async::interrupt
		1551	my $signal = sig2num $arg{signal};
		1552	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1553
		1554	$SIG_ASY{$signal} ||= new Async::Interrupt
		1555	cb => sub { undef $SIG_EV{$signal} },
		1556	signal => $signal,
		1557	pipe => [$SIGPIPE_R->filenos],
		1558	pipe_autodrain => 0,
		1559	;
		1560
		1561	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1562	}
		1563	: sub {
		1564	my (undef, %arg) = @_;
		1565
		1566	# pure perl
		1567	my $signal = sig2name $arg{signal};
		1568	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1569
		1570	$SIG{$signal} ||= sub {
		1571	local $!;
		1572	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
		1573	undef $SIG_EV{$signal};
		1574	};
		1575
		1576	# can't do signal processing without introducing races in pure perl,
		1577	# so limit the signal latency.
		1578	_sig_add;
		1579
		1580	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1581	}
		1582	;
		1583
		1584	*AnyEvent::Base::signal::DESTROY = sub {
		1585	my ($signal, $cb) = @{$_[0]};
		1586
		1587	_sig_del;
		1588
		1589	delete $SIG_CB{$signal}{$cb};
		1590
		1591	$HAVE_ASYNC_INTERRUPT
		1592	? delete $SIG_ASY{$signal}
		1593	: # delete doesn't work with older perls - they then
		1594	# print weird messages, or just unconditionally exit
		1595	# instead of getting the default action.
		1596	undef $SIG{$signal}
		1597	unless keys %{ $SIG_CB{$signal} };
1345	};	1598	};
1346		1599
1347	} else {	1600	*_signal_exec = sub {
1348	# pure perl	1601	$HAVE_ASYNC_INTERRUPT
		1602	? $SIGPIPE_R->drain
		1603	: sysread $SIGPIPE_R, (my $dummy), 9;
1349		1604
1350	$SIG{$signal} ||= sub {	1605	while (%SIG_EV) {
1351	local $!;	1606	for (keys %SIG_EV) {
1352	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;	1607	delete $SIG_EV{$_};
1353	undef $SIG_EV{$signal};	1608	$_->() for values %{ $SIG_CB{$_} || {} };
		1609	}
		1610	}
1354	};	1611	};
1355
1356	# can't do signal processing without introducing races in pure perl,
1357	# so limit the signal latency.
1358	_sig_add;
1359	}	1612	};
		1613	die if $@;
1360		1614
1361	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
1362	}
1363
1364	sub signal {
1365	# probe for availability of Async::Interrupt
1366	if (!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT} && eval "use Async::Interrupt 0.6 (); 1") {
1367	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1368
1369	$HAVE_ASYNC_INTERRUPT = 1;
1370	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1371	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R->fileno, poll => "r", cb => \&_signal_exec);
1372
1373	} else {
1374	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
1375
1376	require Fcntl;
1377
1378	if (AnyEvent::WIN32) {
1379	require AnyEvent::Util;
1380
1381	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1382	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1383	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1384	} else {
1385	pipe $SIGPIPE_R, $SIGPIPE_W;
1386	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
1387	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
1388
1389	# not strictly required, as $^F is normally 2, but let's make sure...
1390	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1391	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1392	}
1393
1394	$SIGPIPE_R
1395	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1396
1397	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1398	}
1399
1400	*signal = \&_signal;
1401	&signal	1615	&signal
1402	}
1403
1404	sub AnyEvent::Base::signal::DESTROY {
1405	my ($signal, $cb) = @{$_[0]};
1406
1407	_sig_del;
1408
1409	delete $SIG_CB{$signal}{$cb};
1410
1411	$HAVE_ASYNC_INTERRUPT
1412	? delete $SIG_ASY{$signal}
1413	: # delete doesn't work with older perls - they then
1414	# print weird messages, or just unconditionally exit
1415	# instead of getting the default action.
1416	undef $SIG{$signal}
1417	unless keys %{ $SIG_CB{$signal} };
1418	}	1616	}
1419		1617
1420	# default implementation for ->child	1618	# default implementation for ->child
1421		1619
1422	our %PID_CB;	1620	our %PID_CB;
1423	our $CHLD_W;	1621	our $CHLD_W;
1424	our $CHLD_DELAY_W;	1622	our $CHLD_DELAY_W;
1425	our $WNOHANG;
1426		1623
1427	sub _sigchld {	1624	# used by many Impl's
1428	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1625	sub _emit_childstatus($$) {
1429	$_->($pid, $?)	1626	my (undef, $rpid, $rstatus) = @_;
		1627
		1628	$_->($rpid, $rstatus)
1430	for values %{ $PID_CB{$pid} || {} },	1629	for values %{ $PID_CB{$rpid} || {} },
1431	values %{ $PID_CB{0} || {} };	1630	values %{ $PID_CB{0} || {} };
1432	}
1433	}	1631	}
1434		1632
1435	sub child {	1633	sub child {
		1634	eval q{ # poor man's autoloading {}
		1635	*_sigchld = sub {
		1636	my $pid;
		1637
		1638	AnyEvent->_emit_childstatus ($pid, $?)
		1639	while ($pid = waitpid -1, WNOHANG) > 0;
		1640	};
		1641
		1642	*child = sub {
1436	my (undef, %arg) = @_;	1643	my (undef, %arg) = @_;
1437		1644
1438	defined (my $pid = $arg{pid} + 0)	1645	defined (my $pid = $arg{pid} + 0)
1439	or Carp::croak "required option 'pid' is missing";	1646	or Carp::croak "required option 'pid' is missing";
1440		1647
1441	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1648	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1442		1649
1443	# WNOHANG is almost cetrainly 1 everywhere
1444	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
1445	? 1
1446	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1447
1448	unless ($CHLD_W) {	1650	unless ($CHLD_W) {
1449	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1651	$CHLD_W = AE::signal CHLD => \&_sigchld;
1450	# child could be a zombie already, so make at least one round	1652	# child could be a zombie already, so make at least one round
1451	&_sigchld;	1653	&_sigchld;
1452	}	1654	}
1453		1655
1454	bless [$pid, $arg{cb}], "AnyEvent::Base::child"	1656	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1455	}	1657	};
1456		1658
1457	sub AnyEvent::Base::child::DESTROY {	1659	*AnyEvent::Base::child::DESTROY = sub {
1458	my ($pid, $cb) = @{$_[0]};	1660	my ($pid, $cb) = @{$_[0]};
1459		1661
1460	delete $PID_CB{$pid}{$cb};	1662	delete $PID_CB{$pid}{$cb};
1461	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1663	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1462		1664
1463	undef $CHLD_W unless keys %PID_CB;	1665	undef $CHLD_W unless keys %PID_CB;
		1666	};
		1667	};
		1668	die if $@;
		1669
		1670	&child
1464	}	1671	}
1465		1672
1466	# idle emulation is done by simply using a timer, regardless	1673	# idle emulation is done by simply using a timer, regardless
1467	# of whether the process is idle or not, and not letting	1674	# of whether the process is idle or not, and not letting
1468	# the callback use more than 50% of the time.	1675	# the callback use more than 50% of the time.
1469	sub idle {	1676	sub idle {
		1677	eval q{ # poor man's autoloading {}
		1678	*idle = sub {
1470	my (undef, %arg) = @_;	1679	my (undef, %arg) = @_;
1471		1680
1472	my ($cb, $w, $rcb) = $arg{cb};	1681	my ($cb, $w, $rcb) = $arg{cb};
1473		1682
1474	$rcb = sub {	1683	$rcb = sub {
1475	if ($cb) {	1684	if ($cb) {
1476	$w = _time;	1685	$w = _time;
1477	&$cb;	1686	&$cb;
1478	$w = _time - $w;	1687	$w = _time - $w;
1479		1688
1480	# never use more then 50% of the time for the idle watcher,	1689	# never use more then 50% of the time for the idle watcher,
1481	# within some limits	1690	# within some limits
1482	$w = 0.0001 if $w < 0.0001;	1691	$w = 0.0001 if $w < 0.0001;
1483	$w = 5 if $w > 5;	1692	$w = 5 if $w > 5;
1484		1693
1485	$w = AnyEvent->timer (after => $w, cb => $rcb);	1694	$w = AE::timer $w, 0, $rcb;
1486	} else {	1695	} else {
1487	# clean up...	1696	# clean up...
1488	undef $w;	1697	undef $w;
1489	undef $rcb;	1698	undef $rcb;
		1699	}
		1700	};
		1701
		1702	$w = AE::timer 0.05, 0, $rcb;
		1703
		1704	bless \\$cb, "AnyEvent::Base::idle"
1490	}	1705	};
		1706
		1707	*AnyEvent::Base::idle::DESTROY = sub {
		1708	undef $${$_[0]};
		1709	};
1491	};	1710	};
		1711	die if $@;
1492		1712
1493	$w = AnyEvent->timer (after => 0.05, cb => $rcb);	1713	&idle
1494
1495	bless \\$cb, "AnyEvent::Base::idle"
1496	}
1497
1498	sub AnyEvent::Base::idle::DESTROY {
1499	undef $${$_[0]};
1500	}	1714	}
1501		1715
1502	package AnyEvent::CondVar;	1716	package AnyEvent::CondVar;
1503		1717
1504	our @ISA = AnyEvent::CondVar::Base::;	1718	our @ISA = AnyEvent::CondVar::Base::;
		1719
		1720	# only to be used for subclassing
		1721	sub new {
		1722	my $class = shift;
		1723	bless AnyEvent->condvar (@_), $class
		1724	}
1505		1725
1506	package AnyEvent::CondVar::Base;	1726	package AnyEvent::CondVar::Base;
1507		1727
1508	#use overload	1728	#use overload
1509	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1729	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
…		…
1552	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1772	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
1553	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1773	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
1554	}	1774	}
1555		1775
1556	sub cb {	1776	sub cb {
1557	$_[0]{_ae_cb} = $_[1] if @_ > 1;	1777	my $cv = shift;
		1778
		1779	@_
		1780	and $cv->{_ae_cb} = shift
		1781	and $cv->{_ae_sent}
		1782	and (delete $cv->{_ae_cb})->($cv);
		1783
1558	$_[0]{_ae_cb}	1784	$cv->{_ae_cb}
1559	}	1785	}
1560		1786
1561	sub begin {	1787	sub begin {
1562	++$_[0]{_ae_counter};	1788	++$_[0]{_ae_counter};
1563	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;	1789	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
…		…
1625	check the arguments passed to most method calls. If it finds any problems,	1851	check the arguments passed to most method calls. If it finds any problems,
1626	it will croak.	1852	it will croak.
1627		1853
1628	In other words, enables "strict" mode.	1854	In other words, enables "strict" mode.
1629		1855
1630	Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>	1856	Unlike C<use strict> (or its modern cousin, C<< use L<common::sense>
1631	>>, it is definitely recommended to keep it off in production. Keeping	1857	>>, it is definitely recommended to keep it off in production. Keeping
1632	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs	1858	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
1633	can be very useful, however.	1859	can be very useful, however.
1634		1860
1635	=item C<PERL_ANYEVENT_MODEL>	1861	=item C<PERL_ANYEVENT_MODEL>
…		…
1772	warn "read: $input\n"; # output what has been read	1998	warn "read: $input\n"; # output what has been read
1773	$cv->send if $input =~ /^q/i; # quit program if /^q/i	1999	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1774	},	2000	},
1775	);	2001	);
1776		2002
1777	my $time_watcher; # can only be used once
1778
1779	sub new_timer {
1780	$timer = AnyEvent->timer (after => 1, cb => sub {	2003	my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1781	warn "timeout\n"; # print 'timeout' about every second	2004	warn "timeout\n"; # print 'timeout' at most every second
1782	&new_timer; # and restart the time
1783	});	2005	});
1784	}
1785
1786	new_timer; # create first timer
1787		2006
1788	$cv->recv; # wait until user enters /^q/i	2007	$cv->recv; # wait until user enters /^q/i
1789		2008
1790	=head1 REAL-WORLD EXAMPLE	2009	=head1 REAL-WORLD EXAMPLE
1791		2010
…		…
1864		2083
1865	The actual code goes further and collects all errors (C<die>s, exceptions)	2084	The actual code goes further and collects all errors (C<die>s, exceptions)
1866	that occurred during request processing. The C<result> method detects	2085	that occurred during request processing. The C<result> method detects
1867	whether an exception as thrown (it is stored inside the $txn object)	2086	whether an exception as thrown (it is stored inside the $txn object)
1868	and just throws the exception, which means connection errors and other	2087	and just throws the exception, which means connection errors and other
1869	problems get reported tot he code that tries to use the result, not in a	2088	problems get reported to the code that tries to use the result, not in a
1870	random callback.	2089	random callback.
1871		2090
1872	All of this enables the following usage styles:	2091	All of this enables the following usage styles:
1873		2092
1874	1. Blocking:	2093	1. Blocking:
…		…
1922	through AnyEvent. The benchmark creates a lot of timers (with a zero	2141	through AnyEvent. The benchmark creates a lot of timers (with a zero
1923	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	2142	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1924	which it is), lets them fire exactly once and destroys them again.	2143	which it is), lets them fire exactly once and destroys them again.
1925		2144
1926	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	2145	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1927	distribution.	2146	distribution. It uses the L<AE> interface, which makes a real difference
		2147	for the EV and Perl backends only.
1928		2148
1929	=head3 Explanation of the columns	2149	=head3 Explanation of the columns
1930		2150
1931	I<watcher> is the number of event watchers created/destroyed. Since	2151	I<watcher> is the number of event watchers created/destroyed. Since
1932	different event models feature vastly different performances, each event	2152	different event models feature vastly different performances, each event
…		…
1953	watcher.	2173	watcher.
1954		2174
1955	=head3 Results	2175	=head3 Results
1956		2176
1957	name watchers bytes create invoke destroy comment	2177	name watchers bytes create invoke destroy comment
1958	EV/EV 400000 224 0.47 0.35 0.27 EV native interface	2178	EV/EV 100000 223 0.47 0.43 0.27 EV native interface
1959	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	2179	EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
1960	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal	2180	Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
1961	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation	2181	Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
1962	Event/Event 16000 517 32.20 31.80 0.81 Event native interface	2182	Event/Event 16000 516 31.16 31.84 0.82 Event native interface
1963	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers	2183	Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
1964	IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll	2184	IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
1965	IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll	2185	IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
1966	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour	2186	Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
1967	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers	2187	Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
1968	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event	2188	POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
1969	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select	2189	POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
1970		2190
1971	=head3 Discussion	2191	=head3 Discussion
1972		2192
1973	The benchmark does I<not> measure scalability of the event loop very	2193	The benchmark does I<not> measure scalability of the event loop very
1974	well. For example, a select-based event loop (such as the pure perl one)	2194	well. For example, a select-based event loop (such as the pure perl one)
…		…
1986	benchmark machine, handling an event takes roughly 1600 CPU cycles with	2206	benchmark machine, handling an event takes roughly 1600 CPU cycles with
1987	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU	2207	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
1988	cycles with POE.	2208	cycles with POE.
1989		2209
1990	C<EV> is the sole leader regarding speed and memory use, which are both	2210	C<EV> is the sole leader regarding speed and memory use, which are both
1991	maximal/minimal, respectively. Even when going through AnyEvent, it uses	2211	maximal/minimal, respectively. When using the L<AE> API there is zero
		2212	overhead (when going through the AnyEvent API create is about 5-6 times
		2213	slower, with other times being equal, so still uses far less memory than
1992	far less memory than any other event loop and is still faster than Event	2214	any other event loop and is still faster than Event natively).
1993	natively.
1994		2215
1995	The pure perl implementation is hit in a few sweet spots (both the	2216	The pure perl implementation is hit in a few sweet spots (both the
1996	constant timeout and the use of a single fd hit optimisations in the perl	2217	constant timeout and the use of a single fd hit optimisations in the perl
1997	interpreter and the backend itself). Nevertheless this shows that it	2218	interpreter and the backend itself). Nevertheless this shows that it
1998	adds very little overhead in itself. Like any select-based backend its	2219	adds very little overhead in itself. Like any select-based backend its
…		…
2072	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100	2293	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
2073	(1%) are active. This mirrors the activity of large servers with many	2294	(1%) are active. This mirrors the activity of large servers with many
2074	connections, most of which are idle at any one point in time.	2295	connections, most of which are idle at any one point in time.
2075		2296
2076	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	2297	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
2077	distribution.	2298	distribution. It uses the L<AE> interface, which makes a real difference
		2299	for the EV and Perl backends only.
2078		2300
2079	=head3 Explanation of the columns	2301	=head3 Explanation of the columns
2080		2302
2081	I<sockets> is the number of sockets, and twice the number of "servers" (as	2303	I<sockets> is the number of sockets, and twice the number of "servers" (as
2082	each server has a read and write socket end).	2304	each server has a read and write socket end).
…		…
2090	a new one that moves the timeout into the future.	2312	a new one that moves the timeout into the future.
2091		2313
2092	=head3 Results	2314	=head3 Results
2093		2315
2094	name sockets create request	2316	name sockets create request
2095	EV 20000 69.01 11.16	2317	EV 20000 62.66 7.99
2096	Perl 20000 73.32 35.87	2318	Perl 20000 68.32 32.64
2097	IOAsync 20000 157.00 98.14 epoll	2319	IOAsync 20000 174.06 101.15 epoll
2098	IOAsync 20000 159.31 616.06 poll	2320	IOAsync 20000 174.67 610.84 poll
2099	Event 20000 212.62 257.32	2321	Event 20000 202.69 242.91
2100	Glib 20000 651.16 1896.30	2322	Glib 20000 557.01 1689.52
2101	POE 20000 349.67 12317.24 uses POE::Loop::Event	2323	POE 20000 341.54 12086.32 uses POE::Loop::Event
2102		2324
2103	=head3 Discussion	2325	=head3 Discussion
2104		2326
2105	This benchmark I<does> measure scalability and overall performance of the	2327	This benchmark I<does> measure scalability and overall performance of the
2106	particular event loop.	2328	particular event loop.
…		…
2232	As you can see, the AnyEvent + EV combination even beats the	2454	As you can see, the AnyEvent + EV combination even beats the
2233	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl	2455	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
2234	backend easily beats IO::Lambda and POE.	2456	backend easily beats IO::Lambda and POE.
2235		2457
2236	And even the 100% non-blocking version written using the high-level (and	2458	And even the 100% non-blocking version written using the high-level (and
2237	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a	2459	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
2238	large margin, even though it does all of DNS, tcp-connect and socket I/O	2460	higher level ("unoptimised") abstractions by a large margin, even though
2239	in a non-blocking way.	2461	it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
2240		2462
2241	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and	2463	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
2242	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are	2464	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
2243	part of the IO::lambda distribution and were used without any changes.	2465	part of the IO::Lambda distribution and were used without any changes.
2244		2466
2245		2467
2246	=head1 SIGNALS	2468	=head1 SIGNALS
2247		2469
2248	AnyEvent currently installs handlers for these signals:	2470	AnyEvent currently installs handlers for these signals:
…		…
2285	unless defined $SIG{PIPE};	2507	unless defined $SIG{PIPE};
2286		2508
2287	=head1 RECOMMENDED/OPTIONAL MODULES	2509	=head1 RECOMMENDED/OPTIONAL MODULES
2288		2510
2289	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and	2511	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
2290	it's built-in modules) are required to use it.	2512	its built-in modules) are required to use it.
2291		2513
2292	That does not mean that AnyEvent won't take advantage of some additional	2514	That does not mean that AnyEvent won't take advantage of some additional
2293	modules if they are installed.	2515	modules if they are installed.
2294		2516
2295	This section epxlains which additional modules will be used, and how they	2517	This section explains which additional modules will be used, and how they
2296	affect AnyEvent's operetion.	2518	affect AnyEvent's operation.
2297		2519
2298	=over 4	2520	=over 4
2299		2521
2300	=item L<Async::Interrupt>	2522	=item L<Async::Interrupt>
2301		2523
…		…
2306	catch the signals) with some delay (default is 10 seconds, look for	2528	catch the signals) with some delay (default is 10 seconds, look for
2307	C<$AnyEvent::MAX_SIGNAL_LATENCY>).	2529	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
2308		2530
2309	If this module is available, then it will be used to implement signal	2531	If this module is available, then it will be used to implement signal
2310	catching, which means that signals will not be delayed, and the event loop	2532	catching, which means that signals will not be delayed, and the event loop
2311	will not be interrupted regularly, which is more efficient (And good for	2533	will not be interrupted regularly, which is more efficient (and good for
2312	battery life on laptops).	2534	battery life on laptops).
2313		2535
2314	This affects not just the pure-perl event loop, but also other event loops	2536	This affects not just the pure-perl event loop, but also other event loops
2315	that have no signal handling on their own (e.g. Glib, Tk, Qt).	2537	that have no signal handling on their own (e.g. Glib, Tk, Qt).
2316		2538
…		…
2328	automatic timer adjustments even when no monotonic clock is available,	2550	automatic timer adjustments even when no monotonic clock is available,
2329	can take avdantage of advanced kernel interfaces such as C<epoll> and	2551	can take avdantage of advanced kernel interfaces such as C<epoll> and
2330	C<kqueue>, and is the fastest backend I<by far>. You can even embed	2552	C<kqueue>, and is the fastest backend I<by far>. You can even embed
2331	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).	2553	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
2332		2554
		2555	If you only use backends that rely on another event loop (e.g. C<Tk>),
		2556	then this module will do nothing for you.
		2557
2333	=item L<Guard>	2558	=item L<Guard>
2334		2559
2335	The guard module, when used, will be used to implement	2560	The guard module, when used, will be used to implement
2336	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a	2561	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
2337	lot less memory), but otherwise doesn't affect guard operation much. It is	2562	lot less memory), but otherwise doesn't affect guard operation much. It is
2338	purely used for performance.	2563	purely used for performance.
2339		2564
2340	=item L<JSON> and L<JSON::XS>	2565	=item L<JSON> and L<JSON::XS>
2341		2566
2342	This module is required when you want to read or write JSON data via	2567	One of these modules is required when you want to read or write JSON data
2343	L<AnyEvent::Handle>. It is also written in pure-perl, but can take	2568	via L<AnyEvent::Handle>. L<JSON> is also written in pure-perl, but can take
2344	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.	2569	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
2345
2346	In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
2347	installed.
2348		2570
2349	=item L<Net::SSLeay>	2571	=item L<Net::SSLeay>
2350		2572
2351	Implementing TLS/SSL in Perl is certainly interesting, but not very	2573	Implementing TLS/SSL in Perl is certainly interesting, but not very
2352	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with	2574	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
2353	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.	2575	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
2354		2576
2355	=item L<Time::HiRes>	2577	=item L<Time::HiRes>
2356		2578
2357	This module is part of perl since release 5.008. It will be used when the	2579	This module is part of perl since release 5.008. It will be used when the
2358	chosen event library does not come with a timing source on it's own. The	2580	chosen event library does not come with a timing source of its own. The
2359	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to	2581	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
2360	try to use a monotonic clock for timing stability.	2582	try to use a monotonic clock for timing stability.
2361		2583
2362	=back	2584	=back
2363		2585
2364		2586
2365	=head1 FORK	2587	=head1 FORK
2366		2588
2367	Most event libraries are not fork-safe. The ones who are usually are	2589	Most event libraries are not fork-safe. The ones who are usually are
2368	because they rely on inefficient but fork-safe C<select> or C<poll>	2590	because they rely on inefficient but fork-safe C<select> or C<poll> calls
2369	calls. Only L<EV> is fully fork-aware.	2591	- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
		2592	are usually badly thought-out hacks that are incompatible with fork in
		2593	one way or another. Only L<EV> is fully fork-aware and ensures that you
		2594	continue event-processing in both parent and child (or both, if you know
		2595	what you are doing).
		2596
		2597	This means that, in general, you cannot fork and do event processing in
		2598	the child if the event library was initialised before the fork (which
		2599	usually happens when the first AnyEvent watcher is created, or the library
		2600	is loaded).
2370		2601
2371	If you have to fork, you must either do so I<before> creating your first	2602	If you have to fork, you must either do so I<before> creating your first
2372	watcher OR you must not use AnyEvent at all in the child OR you must do	2603	watcher OR you must not use AnyEvent at all in the child OR you must do
2373	something completely out of the scope of AnyEvent.	2604	something completely out of the scope of AnyEvent.
		2605
		2606	The problem of doing event processing in the parent I<and> the child
		2607	is much more complicated: even for backends that I<are> fork-aware or
		2608	fork-safe, their behaviour is not usually what you want: fork clones all
		2609	watchers, that means all timers, I/O watchers etc. are active in both
		2610	parent and child, which is almost never what you want. USing C<exec>
		2611	to start worker children from some kind of manage rprocess is usually
		2612	preferred, because it is much easier and cleaner, at the expense of having
		2613	to have another binary.
2374		2614
2375		2615
2376	=head1 SECURITY CONSIDERATIONS	2616	=head1 SECURITY CONSIDERATIONS
2377		2617
2378	AnyEvent can be forced to load any event model via	2618	AnyEvent can be forced to load any event model via
…		…
2408	pronounced).	2648	pronounced).
2409		2649
2410		2650
2411	=head1 SEE ALSO	2651	=head1 SEE ALSO
2412		2652
		2653	Tutorial/Introduction: L<AnyEvent::Intro>.
		2654
		2655	FAQ: L<AnyEvent::FAQ>.
		2656
2413	Utility functions: L<AnyEvent::Util>.	2657	Utility functions: L<AnyEvent::Util>.
2414		2658
2415	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,	2659	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,
2416	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2660	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
2417		2661
2418	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2662	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
2419	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2663	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
2420	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2664	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
2421	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>.	2665	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.
2422		2666
2423	Non-blocking file handles, sockets, TCP clients and	2667	Non-blocking file handles, sockets, TCP clients and
2424	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.	2668	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2425		2669
2426	Asynchronous DNS: L<AnyEvent::DNS>.	2670	Asynchronous DNS: L<AnyEvent::DNS>.
2427		2671
2428	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,	2672	Thread support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>.
2429	L<Coro::Event>,
2430		2673
2431	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,	2674	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::IRC>,
2432	L<AnyEvent::HTTP>.	2675	L<AnyEvent::HTTP>.
2433		2676
2434		2677
2435	=head1 AUTHOR	2678	=head1 AUTHOR
2436		2679

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