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Revision 1.365 by root, Tue Aug 16 14:47:26 2011 UTC

1	=head1 NAME	1	=head1 NAME
2		2
3	AnyEvent - provide framework for multiple event loops	3	AnyEvent - the DBI of event loop programming
4		4
5	EV, Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event loops	5	EV, Event, Glib, Tk, Perl, Event::Lib, Irssi, rxvt-unicode, IO::Async, Qt
		6	and POE are various supported event loops/environments.
6		7
7	=head1 SYNOPSIS	8	=head1 SYNOPSIS
8		9
9	use AnyEvent;	10	use AnyEvent;
10		11
		12	# if you prefer function calls, look at the AE manpage for
		13	# an alternative API.
		14
		15	# file handle or descriptor readable
11	my $w = AnyEvent->io (fh => $fh, poll => "r|w", cb => sub { ... });	16	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });
12		17
		18	# one-shot or repeating timers
13	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });	19	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
14	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...	20	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...);
15		21
16	print AnyEvent->now; # prints current event loop time	22	print AnyEvent->now; # prints current event loop time
17	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.	23	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
18		24
		25	# POSIX signal
19	my $w = AnyEvent->signal (signal => "TERM", cb => sub { ... });	26	my $w = AnyEvent->signal (signal => "TERM", cb => sub { ... });
20		27
		28	# child process exit
21	my $w = AnyEvent->child (pid => $pid, cb => sub {	29	my $w = AnyEvent->child (pid => $pid, cb => sub {
22	my ($pid, $status) = @_;	30	my ($pid, $status) = @_;
23	...	31	...
24	});	32	});
		33
		34	# called when event loop idle (if applicable)
		35	my $w = AnyEvent->idle (cb => sub { ... });
25		36
26	my $w = AnyEvent->condvar; # stores whether a condition was flagged	37	my $w = AnyEvent->condvar; # stores whether a condition was flagged
27	$w->send; # wake up current and all future recv's	38	$w->send; # wake up current and all future recv's
28	$w->recv; # enters "main loop" till $condvar gets ->send	39	$w->recv; # enters "main loop" till $condvar gets ->send
29	# use a condvar in callback mode:	40	# use a condvar in callback mode:
…		…
32	=head1 INTRODUCTION/TUTORIAL	43	=head1 INTRODUCTION/TUTORIAL
33		44
34	This manpage is mainly a reference manual. If you are interested	45	This manpage is mainly a reference manual. If you are interested
35	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
36	L<AnyEvent::Intro> manpage.	47	L<AnyEvent::Intro> manpage.
		48
		49	=head1 SUPPORT
		50
		51	An FAQ document is available as L<AnyEvent::FAQ>.
		52
		53	There also is a mailinglist for discussing all things AnyEvent, and an IRC
		54	channel, too.
		55
		56	See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software
		57	Repository>, at L<http://anyevent.schmorp.de>, for more info.
37		58
38	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)	59	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
39		60
40	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
41	nowadays. So what is different about AnyEvent?	62	nowadays. So what is different about AnyEvent?
…		…
57	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
58	model you use.	79	model you use.
59		80
60	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
61	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
62	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
63	cannot use anything else, as they are simply incompatible to everything	84	cannot use anything else, as they are simply incompatible to everything
64	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
65	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.
66		87
67	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works	88	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
68	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
69	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
70	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
71	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
72	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
73	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,
74	to AnyEvent, too, so it is future-proof).	95	so it is future-proof).
75		96
76	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
77	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
78	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
79	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
80	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
81	technically possible.	102	technically possible.
82		103
83	Of course, AnyEvent comes with a big (and fully optional!) toolbox	104	Of course, AnyEvent comes with a big (and fully optional!) toolbox
84	of useful functionality, such as an asynchronous DNS resolver, 100%	105	of useful functionality, such as an asynchronous DNS resolver, 100%
…		…
90	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
91	model, you should I<not> use this module.	112	model, you should I<not> use this module.
92		113
93	=head1 DESCRIPTION	114	=head1 DESCRIPTION
94		115
95	L<AnyEvent> provides an identical interface to multiple event loops. This	116	L<AnyEvent> provides a uniform interface to various event loops. This
96	allows module authors to utilise an event loop without forcing module	117	allows module authors to use event loop functionality without forcing
97	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
98	peacefully at any one time).	119	than one event loop cannot coexist peacefully).
99		120
100	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>
101	module.	122	module.
102		123
103	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
104	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
105	following modules is already loaded: L<EV>,	126	following modules is already loaded: L<EV>, L<AnyEvent::Loop>,
106	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
107	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
108	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
109	adaptor should always succeed) in the order given. The first one that can	130	available, the pure-perl L<AnyEvent::Loop> should always work, so
110	be successfully loaded will be used. If, after this, still none could be	131	the other two are not normally tried.
111	found, AnyEvent will fall back to a pure-perl event loop, which is not
112	very efficient, but should work everywhere.
113		132
114	Because AnyEvent first checks for modules that are already loaded, loading	133	Because AnyEvent first checks for modules that are already loaded, loading
115	an event model explicitly before first using AnyEvent will likely make	134	an event model explicitly before first using AnyEvent will likely make
116	that model the default. For example:	135	that model the default. For example:
117		136
…		…
119	use AnyEvent;	138	use AnyEvent;
120		139
121	# .. AnyEvent will likely default to Tk	140	# .. AnyEvent will likely default to Tk
122		141
123	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
124	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,
125	use AnyEvent so their modules work together with others seamlessly...	144	as very few modules hardcode event loops without announcing this very
		145	loudly.
126		146
127	The pure-perl implementation of AnyEvent is called	147	The pure-perl implementation of AnyEvent is called C<AnyEvent::Loop>. Like
128	C<AnyEvent::Impl::Perl>. Like other event modules you can load it	148	other event modules you can load it explicitly and enjoy the high
129	explicitly and enjoy the high availability of that event loop :)	149	availability of that event loop :)
130		150
131	=head1 WATCHERS	151	=head1 WATCHERS
132		152
133	AnyEvent has the central concept of a I<watcher>, which is an object that	153	AnyEvent has the central concept of a I<watcher>, which is an object that
134	stores relevant data for each kind of event you are waiting for, such as	154	stores relevant data for each kind of event you are waiting for, such as
…		…
139	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
140	is in control).	160	is in control).
141		161
142	Note that B<callbacks must not permanently change global variables>	162	Note that B<callbacks must not permanently change global variables>
143	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<<
144	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
145	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
146	widely between event loops.	166	widely between event loops.
147		167
148	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
149	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
150	to it).	170	to it).
151		171
152	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.
153		173
154	Many watchers either are used with "recursion" (repeating timers for	174	Many watchers either are used with "recursion" (repeating timers for
155	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.
156		176
157	An any way to achieve that is this pattern:	177	One way to achieve that is this pattern:
158		178
159	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {	179	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
160	# you can use $w here, for example to undef it	180	# you can use $w here, for example to undef it
161	undef $w;	181	undef $w;
162	});	182	});
…		…
165	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
166	declared.	186	declared.
167		187
168	=head2 I/O WATCHERS	188	=head2 I/O WATCHERS
169		189
		190	$w = AnyEvent->io (
		191	fh => <filehandle_or_fileno>,
		192	poll => <"r" or "w">,
		193	cb => <callback>,
		194	);
		195
170	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
171	with the following mandatory key-value pairs as arguments:	197	with the following mandatory key-value pairs as arguments:
172		198
173	C<fh> is the Perl I<file handle> (I<not> file descriptor) to watch	199	C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch
174	for events (AnyEvent might or might not keep a reference to this file	200	for events (AnyEvent might or might not keep a reference to this file
175	handle). Note that only file handles pointing to things for which	201	handle). Note that only file handles pointing to things for which
176	non-blocking operation makes sense are allowed. This includes sockets,	202	non-blocking operation makes sense are allowed. This includes sockets,
177	most character devices, pipes, fifos and so on, but not for example files	203	most character devices, pipes, fifos and so on, but not for example files
178	or block devices.	204	or block devices.
…		…
188		214
189	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.
190	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
191	underlying file descriptor.	217	underlying file descriptor.
192		218
193	Some event loops issue spurious readyness notifications, so you should	219	Some event loops issue spurious readiness notifications, so you should
194	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
195	handles.	221	handles.
196		222
197	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
198	watcher.	224	watcher.
…		…
203	undef $w;	229	undef $w;
204	});	230	});
205		231
206	=head2 TIME WATCHERS	232	=head2 TIME WATCHERS
207		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
208	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 >>
209	method with the following mandatory arguments:	243	method with the following mandatory arguments:
210		244
211	C<after> specifies after how many seconds (fractional values are	245	C<after> specifies after how many seconds (fractional values are
212	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
…		…
214		248
215	Although the callback might get passed parameters, their value and	249	Although the callback might get passed parameters, their value and
216	presence is undefined and you cannot rely on them. Portable AnyEvent	250	presence is undefined and you cannot rely on them. Portable AnyEvent
217	callbacks cannot use arguments passed to time watcher callbacks.	251	callbacks cannot use arguments passed to time watcher callbacks.
218		252
219	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
220	parameter, C<interval>, as a strictly positive number (> 0), then the	254	parameter, C<interval>, as a strictly positive number (> 0), then the
221	callback will be invoked regularly at that interval (in fractional	255	callback will be invoked regularly at that interval (in fractional
222	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
223	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.
224		258
225	The callback will be rescheduled before invoking the callback, but no	259	The callback will be rescheduled before invoking the callback, but no
226	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
227	only approximate.	261	only approximate.
228		262
229	Example: fire an event after 7.7 seconds.	263	Example: fire an event after 7.7 seconds.
230		264
231	my $w = AnyEvent->timer (after => 7.7, cb => sub {	265	my $w = AnyEvent->timer (after => 7.7, cb => sub {
…		…
249		283
250	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
251	use absolute time internally. This makes a difference when your clock	285	use absolute time internally. This makes a difference when your clock
252	"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
253	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
254	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.
255		289
256	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
257	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
258	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)
259	timers.	293	timers.
260		294
261	AnyEvent always prefers relative timers, if available, matching the	295	AnyEvent always prefers relative timers, if available, matching the
262	AnyEvent API.	296	AnyEvent API.
…		…
284	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
285	function to call when you want to know the current time.>	319	function to call when you want to know the current time.>
286		320
287	This function is also often faster then C<< AnyEvent->time >>, and	321	This function is also often faster then C<< AnyEvent->time >>, and
288	thus the preferred method if you want some timestamp (for example,	322	thus the preferred method if you want some timestamp (for example,
289	L<AnyEvent::Handle> uses this to update it's activity timeouts).	323	L<AnyEvent::Handle> uses this to update its activity timeouts).
290		324
291	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
292	with your timing, you can skip it without bad conscience.	326	with your timing; you can skip it without a bad conscience.
293		327
294	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>
295	and L<EV> and the following set-up:	329	and L<EV> and the following set-up:
296		330
297	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
298	time=500 (assume no other callbacks delay processing). In your callback,	332	time=500 (assume no other callbacks delay processing). In your callback,
299	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
300	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
301	after three seconds.	335	after three seconds.
302		336
…		…
322	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into	356	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
323	account.	357	account.
324		358
325	=item AnyEvent->now_update	359	=item AnyEvent->now_update
326		360
327	Some event loops (such as L<EV> or L<AnyEvent::Impl::Perl>) cache	361	Some event loops (such as L<EV> or L<AnyEvent::Loop>) cache the current
328	the current time for each loop iteration (see the discussion of L<<	362	time for each loop iteration (see the discussion of L<< AnyEvent->now >>,
329	AnyEvent->now >>, above).	363	above).
330		364
331	When a callback runs for a long time (or when the process sleeps), then	365	When a callback runs for a long time (or when the process sleeps), then
332	this "current" time will differ substantially from the real time, which	366	this "current" time will differ substantially from the real time, which
333	might affect timers and time-outs.	367	might affect timers and time-outs.
334		368
335	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
336	event loop's idea of "current time".	370	event loop's idea of "current time".
337		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
338	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.
339		380
340	=back	381	=back
341		382
342	=head2 SIGNAL WATCHERS	383	=head2 SIGNAL WATCHERS
		384
		385	$w = AnyEvent->signal (signal => <uppercase_signal_name>, cb => <callback>);
343		386
344	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
345	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
346	callback to be invoked whenever a signal occurs.	389	callback to be invoked whenever a signal occurs.
347		390
…		…
353	invocation, and callback invocation will be synchronous. Synchronous means	396	invocation, and callback invocation will be synchronous. Synchronous means
354	that it might take a while until the signal gets handled by the process,	397	that it might take a while until the signal gets handled by the process,
355	but it is guaranteed not to interrupt any other callbacks.	398	but it is guaranteed not to interrupt any other callbacks.
356		399
357	The main advantage of using these watchers is that you can share a signal	400	The main advantage of using these watchers is that you can share a signal
358	between multiple watchers.	401	between multiple watchers, and AnyEvent will ensure that signals will not
		402	interrupt your program at bad times.
359		403
360	This watcher might use C<%SIG>, so programs overwriting those signals	404	This watcher might use C<%SIG> (depending on the event loop used),
361	directly will likely not work correctly.	405	so programs overwriting those signals directly will likely not work
		406	correctly.
362		407
363	Example: exit on SIGINT	408	Example: exit on SIGINT
364		409
365	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });	410	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
366		411
		412	=head3 Restart Behaviour
		413
		414	While restart behaviour is up to the event loop implementation, most will
		415	not restart syscalls (that includes L<Async::Interrupt> and AnyEvent's
		416	pure perl implementation).
		417
		418	=head3 Safe/Unsafe Signals
		419
		420	Perl signals can be either "safe" (synchronous to opcode handling) or
		421	"unsafe" (asynchronous) - the former might get delayed indefinitely, the
		422	latter might corrupt your memory.
		423
		424	AnyEvent signal handlers are, in addition, synchronous to the event loop,
		425	i.e. they will not interrupt your running perl program but will only be
		426	called as part of the normal event handling (just like timer, I/O etc.
		427	callbacks, too).
		428
		429	=head3 Signal Races, Delays and Workarounds
		430
		431	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
		432	callbacks to signals in a generic way, which is a pity, as you cannot
		433	do race-free signal handling in perl, requiring C libraries for
		434	this. AnyEvent will try to do its best, which means in some cases,
		435	signals will be delayed. The maximum time a signal might be delayed is
		436	specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This
		437	variable can be changed only before the first signal watcher is created,
		438	and should be left alone otherwise. This variable determines how often
		439	AnyEvent polls for signals (in case a wake-up was missed). Higher values
		440	will cause fewer spurious wake-ups, which is better for power and CPU
		441	saving.
		442
		443	All these problems can be avoided by installing the optional
		444	L<Async::Interrupt> module, which works with most event loops. It will not
		445	work with inherently broken event loops such as L<Event> or L<Event::Lib>
		446	(and not with L<POE> currently, as POE does its own workaround with
		447	one-second latency). For those, you just have to suffer the delays.
		448
367	=head2 CHILD PROCESS WATCHERS	449	=head2 CHILD PROCESS WATCHERS
368		450
		451	$w = AnyEvent->child (pid => <process id>, cb => <callback>);
		452
369	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.
370		454
371	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,
372	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
373	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
374	any trace events (stopped/continued).	458	finished and an exit status is available, not on any trace events
		459	(stopped/continued).
375		460
376	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
377	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
378	callback arguments.	463	callback arguments.
379		464
…		…
384		469
385	There is a slight catch to child watchers, however: you usually start them	470	There is a slight catch to child watchers, however: you usually start them
386	I<after> the child process was created, and this means the process could	471	I<after> the child process was created, and this means the process could
387	have exited already (and no SIGCHLD will be sent anymore).	472	have exited already (and no SIGCHLD will be sent anymore).
388		473
389	Not all event models handle this correctly (POE doesn't), but even for	474	Not all event models handle this correctly (neither POE nor IO::Async do,
		475	see their AnyEvent::Impl manpages for details), but even for event models
390	event models that I<do> handle this correctly, they usually need to be	476	that I<do> handle this correctly, they usually need to be loaded before
391	loaded before the process exits (i.e. before you fork in the first place).	477	the process exits (i.e. before you fork in the first place). AnyEvent's
		478	pure perl event loop handles all cases correctly regardless of when you
		479	start the watcher.
392		480
393	This means you cannot create a child watcher as the very first thing in an	481	This means you cannot create a child watcher as the very first
394	AnyEvent program, you I<have> to create at least one watcher before you	482	thing in an AnyEvent program, you I<have> to create at least one
395	C<fork> the child (alternatively, you can call C<AnyEvent::detect>).	483	watcher before you C<fork> the child (alternatively, you can call
		484	C<AnyEvent::detect>).
		485
		486	As most event loops do not support waiting for child events, they will be
		487	emulated by AnyEvent in most cases, in which case the latency and race
		488	problems mentioned in the description of signal watchers apply.
396		489
397	Example: fork a process and wait for it	490	Example: fork a process and wait for it
398		491
399	my $done = AnyEvent->condvar;	492	my $done = AnyEvent->condvar;
400		493
…		…
410	);	503	);
411		504
412	# do something else, then wait for process exit	505	# do something else, then wait for process exit
413	$done->recv;	506	$done->recv;
414		507
		508	=head2 IDLE WATCHERS
		509
		510	$w = AnyEvent->idle (cb => <callback>);
		511
		512	This will repeatedly invoke the callback after the process becomes idle,
		513	until either the watcher is destroyed or new events have been detected.
		514
		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
		525	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
		526	will simply call the callback "from time to time".
		527
		528	Example: read lines from STDIN, but only process them when the
		529	program is otherwise idle:
		530
		531	my @lines; # read data
		532	my $idle_w;
		533	my $io_w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
		534	push @lines, scalar <STDIN>;
		535
		536	# start an idle watcher, if not already done
		537	$idle_w ||= AnyEvent->idle (cb => sub {
		538	# handle only one line, when there are lines left
		539	if (my $line = shift @lines) {
		540	print "handled when idle: $line";
		541	} else {
		542	# otherwise disable the idle watcher again
		543	undef $idle_w;
		544	}
		545	});
		546	});
		547
415	=head2 CONDITION VARIABLES	548	=head2 CONDITION VARIABLES
		549
		550	$cv = AnyEvent->condvar;
		551
		552	$cv->send (<list>);
		553	my @res = $cv->recv;
416		554
417	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
418	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
419	will actively watch for new events and call your callbacks.	557	will actively watch for new events and call your callbacks.
420		558
421	AnyEvent is different, it expects somebody else to run the event loop and	559	AnyEvent is slightly different: it expects somebody else to run the event
422	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).
423		561
424	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
425	because they represent a condition that must become true.	563	they represent a condition that must become true.
		564
		565	Now is probably a good time to look at the examples further below.
426		566
427	Condition variables can be created by calling the C<< AnyEvent->condvar	567	Condition variables can be created by calling the C<< AnyEvent->condvar
428	>> method, usually without arguments. The only argument pair allowed is	568	>> method, usually without arguments. The only argument pair allowed is
429
430	C<cb>, which specifies a callback to be called when the condition variable	569	C<cb>, which specifies a callback to be called when the condition variable
431	becomes true, with the condition variable as the first argument (but not	570	becomes true, with the condition variable as the first argument (but not
432	the results).	571	the results).
433		572
434	After creation, the condition variable is "false" until it becomes "true"	573	After creation, the condition variable is "false" until it becomes "true"
435	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
436	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<<
437	->send >> method).	576	->send >> method).
438		577
439	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
440	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:
441	in time where multiple outstanding events have been processed. And yet	580
442	another way to call them is transactions - each condition variable can be	581	=over 4
443	used to represent a transaction, which finishes at some point and delivers	582
444	a result.	583	=item * Condition variables are like callbacks - you can call them (and pass them instead
		584	of callbacks). Unlike callbacks however, you can also wait for them to be called.
		585
		586	=item * Condition variables are signals - one side can emit or send them,
		587	the other side can wait for them, or install a handler that is called when
		588	the signal fires.
		589
		590	=item * Condition variables are like "Merge Points" - points in your program
		591	where you merge multiple independent results/control flows into one.
		592
		593	=item * Condition variables represent a transaction - functions that start
		594	some kind of transaction can return them, leaving the caller the choice
		595	between waiting in a blocking fashion, or setting a callback.
		596
		597	=item * Condition variables represent future values, or promises to deliver
		598	some result, long before the result is available.
		599
		600	=back
445		601
446	Condition variables are very useful to signal that something has finished,	602	Condition variables are very useful to signal that something has finished,
447	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,
448	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
449	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
…		…
462		618
463	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
464	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
465	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
466	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
467	it's C<new> method in your own C<new> method.	623	its C<new> method in your own C<new> method.
468		624
469	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
470	eventually calls C<< -> send >>, and the "consumer side", which waits	626	eventually calls C<< -> send >>, and the "consumer side", which waits
471	for the send to occur.	627	for the send to occur.
472		628
473	Example: wait for a timer.	629	Example: wait for a timer.
474		630
475	# wait till the result is ready	631	# condition: "wait till the timer is fired"
476	my $result_ready = AnyEvent->condvar;	632	my $timer_fired = AnyEvent->condvar;
477		633
478	# do something such as adding a timer	634	# create the timer - we could wait for, say
479	# or socket watcher the calls $result_ready->send	635	# a handle becomign ready, or even an
480	# when the "result" is ready.	636	# AnyEvent::HTTP request to finish, but
481	# in this case, we simply use a timer:	637	# in this case, we simply use a timer:
482	my $w = AnyEvent->timer (	638	my $w = AnyEvent->timer (
483	after => 1,	639	after => 1,
484	cb => sub { $result_ready->send },	640	cb => sub { $timer_fired->send },
485	);	641	);
486		642
487	# this "blocks" (while handling events) till the callback	643	# this "blocks" (while handling events) till the callback
488	# calls send	644	# calls ->send
489	$result_ready->recv;	645	$timer_fired->recv;
490		646
491	Example: wait for a timer, but take advantage of the fact that	647	Example: wait for a timer, but take advantage of the fact that condition
492	condition variables are also code references.	648	variables are also callable directly.
493		649
494	my $done = AnyEvent->condvar;	650	my $done = AnyEvent->condvar;
495	my $delay = AnyEvent->timer (after => 5, cb => $done);	651	my $delay = AnyEvent->timer (after => 5, cb => $done);
496	$done->recv;	652	$done->recv;
497		653
…		…
503		659
504	...	660	...
505		661
506	my @info = $couchdb->info->recv;	662	my @info = $couchdb->info->recv;
507		663
508	And this is how you would just ste a callback to be called whenever the	664	And this is how you would just set a callback to be called whenever the
509	results are available:	665	results are available:
510		666
511	$couchdb->info->cb (sub {	667	$couchdb->info->cb (sub {
512	my @info = $_[0]->recv;	668	my @info = $_[0]->recv;
513	});	669	});
…		…
531	immediately from within send.	687	immediately from within send.
532		688
533	Any arguments passed to the C<send> call will be returned by all	689	Any arguments passed to the C<send> call will be returned by all
534	future C<< ->recv >> calls.	690	future C<< ->recv >> calls.
535		691
536	Condition variables are overloaded so one can call them directly	692	Condition variables are overloaded so one can call them directly (as if
537	(as a code reference). Calling them directly is the same as calling	693	they were a code reference). Calling them directly is the same as calling
538	C<send>. Note, however, that many C-based event loops do not handle	694	C<send>.
539	overloading, so as tempting as it may be, passing a condition variable
540	instead of a callback does not work. Both the pure perl and EV loops
541	support overloading, however, as well as all functions that use perl to
542	invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
543	example).
544		695
545	=item $cv->croak ($error)	696	=item $cv->croak ($error)
546		697
547	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
548	C<Carp::croak> with the given error message/object/scalar.	699	C<Carp::croak> with the given error message/object/scalar.
549		700
550	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
551	user/consumer.	702	user/consumer. Doing it this way instead of calling C<croak> directly
		703	delays the error detection, but has the overwhelming advantage that it
		704	diagnoses the error at the place where the result is expected, and not
		705	deep in some event callback with no connection to the actual code causing
		706	the problem.
552		707
553	=item $cv->begin ([group callback])	708	=item $cv->begin ([group callback])
554		709
555	=item $cv->end	710	=item $cv->end
556
557	These two methods are EXPERIMENTAL and MIGHT CHANGE.
558		711
559	These two methods can be used to combine many transactions/events into	712	These two methods can be used to combine many transactions/events into
560	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
561	to use a condition variable for the whole process.	714	to use a condition variable for the whole process.
562		715
563	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
564	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
565	>>, 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
566	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
567	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.
568		722
569	Let's clarify this with the ping example:	723	You can think of C<< $cv->send >> giving you an OR condition (one call
		724	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
		725	condition (all C<begin> calls must be C<end>'ed before the condvar sends).
		726
		727	Let's start with a simple example: you have two I/O watchers (for example,
		728	STDOUT and STDERR for a program), and you want to wait for both streams to
		729	close before activating a condvar:
570		730
571	my $cv = AnyEvent->condvar;	731	my $cv = AnyEvent->condvar;
572		732
		733	$cv->begin; # first watcher
		734	my $w1 = AnyEvent->io (fh => $fh1, cb => sub {
		735	defined sysread $fh1, my $buf, 4096
		736	or $cv->end;
		737	});
		738
		739	$cv->begin; # second watcher
		740	my $w2 = AnyEvent->io (fh => $fh2, cb => sub {
		741	defined sysread $fh2, my $buf, 4096
		742	or $cv->end;
		743	});
		744
		745	$cv->recv;
		746
		747	This works because for every event source (EOF on file handle), there is
		748	one call to C<begin>, so the condvar waits for all calls to C<end> before
		749	sending.
		750
		751	The ping example mentioned above is slightly more complicated, as the
		752	there are results to be passwd back, and the number of tasks that are
		753	begun can potentially be zero:
		754
		755	my $cv = AnyEvent->condvar;
		756
573	my %result;	757	my %result;
574	$cv->begin (sub { $cv->send (\%result) });	758	$cv->begin (sub { shift->send (\%result) });
575		759
576	for my $host (@list_of_hosts) {	760	for my $host (@list_of_hosts) {
577	$cv->begin;	761	$cv->begin;
578	ping_host_then_call_callback $host, sub {	762	ping_host_then_call_callback $host, sub {
579	$result{$host} = ...;	763	$result{$host} = ...;
…		…
594	loop, which serves two important purposes: first, it sets the callback	778	loop, which serves two important purposes: first, it sets the callback
595	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
596	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
597	doesn't execute once).	781	doesn't execute once).
598		782
599	This is the general pattern when you "fan out" into multiple subrequests:	783	This is the general pattern when you "fan out" into multiple (but
600	use an outer C<begin>/C<end> pair to set the callback and ensure C<end>	784	potentially zero) subrequests: use an outer C<begin>/C<end> pair to set
601	is called at least once, and then, for each subrequest you start, call	785	the callback and ensure C<end> is called at least once, and then, for each
602	C<begin> and for each subrequest you finish, call C<end>.	786	subrequest you start, call C<begin> and for each subrequest you finish,
		787	call C<end>.
603		788
604	=back	789	=back
605		790
606	=head3 METHODS FOR CONSUMERS	791	=head3 METHODS FOR CONSUMERS
607		792
…		…
611	=over 4	796	=over 4
612		797
613	=item $cv->recv	798	=item $cv->recv
614		799
615	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak	800	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
616	>> methods have been called on c<$cv>, while servicing other watchers	801	>> methods have been called on C<$cv>, while servicing other watchers
617	normally.	802	normally.
618		803
619	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
620	will return immediately.	805	will return immediately.
621		806
…		…
623	function will call C<croak>.	808	function will call C<croak>.
624		809
625	In list context, all parameters passed to C<send> will be returned,	810	In list context, all parameters passed to C<send> will be returned,
626	in scalar context only the first one will be returned.	811	in scalar context only the first one will be returned.
627		812
		813	Note that doing a blocking wait in a callback is not supported by any
		814	event loop, that is, recursive invocation of a blocking C<< ->recv
		815	>> is not allowed, and the C<recv> call will C<croak> if such a
		816	condition is detected. This condition can be slightly loosened by using
		817	L<Coro::AnyEvent>, which allows you to do a blocking C<< ->recv >> from
		818	any thread that doesn't run the event loop itself.
		819
628	Not all event models support a blocking wait - some die in that case	820	Not all event models support a blocking wait - some die in that case
629	(programs might want to do that to stay interactive), so I<if you are	821	(programs might want to do that to stay interactive), so I<if you are
630	using this from a module, never require a blocking wait>, but let the	822	using this from a module, never require a blocking wait>. Instead, let the
631	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
632	condition variables with some kind of request results and supporting	824	condition variables with some kind of request results and supporting
633	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,
634	while still supporting blocking waits if the caller so desires).	826	while still supporting blocking waits if the caller so desires).
635		827
636	Another reason I<never> to C<< ->recv >> in a module is that you cannot
637	sensibly have two C<< ->recv >>'s in parallel, as that would require
638	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
639	can supply.
640
641	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
642	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
643	versions and also integrates coroutines into AnyEvent, making blocking
644	C<< ->recv >> calls perfectly safe as long as they are done from another
645	coroutine (one that doesn't run the event loop).
646
647	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
648	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
649	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
650	waits otherwise.	831	waits otherwise.
651		832
652	=item $bool = $cv->ready	833	=item $bool = $cv->ready
…		…
658		839
659	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
660	replaces it before doing so.	841	replaces it before doing so.
661		842
662	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
663	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
664	variable itself. Calling C<recv> inside the callback or at any later time	845	condition variable itself. If the condition is already true, the
665	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.
666		848
667	=back	849	=back
668		850
		851	=head1 SUPPORTED EVENT LOOPS/BACKENDS
		852
		853	The available backend classes are (every class has its own manpage):
		854
		855	=over 4
		856
		857	=item Backends that are autoprobed when no other event loop can be found.
		858
		859	EV is the preferred backend when no other event loop seems to be in
		860	use. If EV is not installed, then AnyEvent will fall back to its own
		861	pure-perl implementation, which is available everywhere as it comes with
		862	AnyEvent itself.
		863
		864	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
		865	AnyEvent::Impl::Perl pure-perl AnyEvent::Loop, fast and portable.
		866
		867	=item Backends that are transparently being picked up when they are used.
		868
		869	These will be used if they are already loaded when the first watcher
		870	is created, in which case it is assumed that the application is using
		871	them. This means that AnyEvent will automatically pick the right backend
		872	when the main program loads an event module before anything starts to
		873	create watchers. Nothing special needs to be done by the main program.
		874
		875	AnyEvent::Impl::Event based on Event, very stable, few glitches.
		876	AnyEvent::Impl::Glib based on Glib, slow but very stable.
		877	AnyEvent::Impl::Tk based on Tk, very broken.
		878	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
		879	AnyEvent::Impl::POE based on POE, very slow, some limitations.
		880	AnyEvent::Impl::Irssi used when running within irssi.
		881	AnyEvent::Impl::IOAsync based on IO::Async.
		882	AnyEvent::Impl::Cocoa based on Cocoa::EventLoop.
		883	AnyEvent::Impl::FLTK2 based on FLTK (fltk 2 binding).
		884
		885	=item Backends with special needs.
		886
		887	Qt requires the Qt::Application to be instantiated first, but will
		888	otherwise be picked up automatically. As long as the main program
		889	instantiates the application before any AnyEvent watchers are created,
		890	everything should just work.
		891
		892	AnyEvent::Impl::Qt based on Qt.
		893
		894	=item Event loops that are indirectly supported via other backends.
		895
		896	Some event loops can be supported via other modules:
		897
		898	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
		899
		900	B<WxWidgets> has no support for watching file handles. However, you can
		901	use WxWidgets through the POE adaptor, as POE has a Wx backend that simply
		902	polls 20 times per second, which was considered to be too horrible to even
		903	consider for AnyEvent.
		904
		905	B<Prima> is not supported as nobody seems to be using it, but it has a POE
		906	backend, so it can be supported through POE.
		907
		908	AnyEvent knows about both L<Prima> and L<Wx>, however, and will try to
		909	load L<POE> when detecting them, in the hope that POE will pick them up,
		910	in which case everything will be automatic.
		911
		912	=back
		913
669	=head1 GLOBAL VARIABLES AND FUNCTIONS	914	=head1 GLOBAL VARIABLES AND FUNCTIONS
670		915
		916	These are not normally required to use AnyEvent, but can be useful to
		917	write AnyEvent extension modules.
		918
671	=over 4	919	=over 4
672		920
673	=item $AnyEvent::MODEL	921	=item $AnyEvent::MODEL
674		922
675	Contains C<undef> until the first watcher is being created. Then it	923	Contains C<undef> until the first watcher is being created, before the
		924	backend has been autodetected.
		925
676	contains the event model that is being used, which is the name of the	926	Afterwards it contains the event model that is being used, which is the
677	Perl class implementing the model. This class is usually one of the	927	name of the Perl class implementing the model. This class is usually one
678	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	928	of the C<AnyEvent::Impl::xxx> modules, but can be any other class in the
679	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	929	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
680		930	will be C<urxvt::anyevent>).
681	The known classes so far are:
682
683	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
684	AnyEvent::Impl::Event based on Event, second best choice.
685	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
686	AnyEvent::Impl::Glib based on Glib, third-best choice.
687	AnyEvent::Impl::Tk based on Tk, very bad choice.
688	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
689	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
690	AnyEvent::Impl::POE based on POE, not generic enough for full support.
691
692	There is no support for WxWidgets, as WxWidgets has no support for
693	watching file handles. However, you can use WxWidgets through the
694	POE Adaptor, as POE has a Wx backend that simply polls 20 times per
695	second, which was considered to be too horrible to even consider for
696	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
697	it's adaptor.
698
699	AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
700	autodetecting them.
701		931
702	=item AnyEvent::detect	932	=item AnyEvent::detect
703		933
704	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	934	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
705	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
706	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
707	runtime.	937	runtime, and not e.g. during initialisation of your module.
		938
		939	The effect of calling this function is as if a watcher had been created
		940	(specifically, actions that happen "when the first watcher is created"
		941	happen when calling detetc as well).
		942
		943	If you need to do some initialisation before AnyEvent watchers are
		944	created, use C<post_detect>.
708		945
709	=item $guard = AnyEvent::post_detect { BLOCK }	946	=item $guard = AnyEvent::post_detect { BLOCK }
710		947
711	Arranges for the code block to be executed as soon as the event model is	948	Arranges for the code block to be executed as soon as the event model is
712	autodetected (or immediately if this has already happened).	949	autodetected (or immediately if that has already happened).
		950
		951	The block will be executed I<after> the actual backend has been detected
		952	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
		953	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
		954	other initialisations - see the sources of L<AnyEvent::Strict> or
		955	L<AnyEvent::AIO> to see how this is used.
		956
		957	The most common usage is to create some global watchers, without forcing
		958	event module detection too early, for example, L<AnyEvent::AIO> creates
		959	and installs the global L<IO::AIO> watcher in a C<post_detect> block to
		960	avoid autodetecting the event module at load time.
713		961
714	If called in scalar or list context, then it creates and returns an object	962	If called in scalar or list context, then it creates and returns an object
715	that automatically removes the callback again when it is destroyed. See	963	that automatically removes the callback again when it is destroyed (or
		964	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
716	L<Coro::BDB> for a case where this is useful.	965	a case where this is useful.
		966
		967	Example: Create a watcher for the IO::AIO module and store it in
		968	C<$WATCHER>, but do so only do so after the event loop is initialised.
		969
		970	our WATCHER;
		971
		972	my $guard = AnyEvent::post_detect {
		973	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
		974	};
		975
		976	# the ||= is important in case post_detect immediately runs the block,
		977	# as to not clobber the newly-created watcher. assigning both watcher and
		978	# post_detect guard to the same variable has the advantage of users being
		979	# able to just C<undef $WATCHER> if the watcher causes them grief.
		980
		981	$WATCHER ||= $guard;
717		982
718	=item @AnyEvent::post_detect	983	=item @AnyEvent::post_detect
719		984
720	If there are any code references in this array (you can C<push> to it	985	If there are any code references in this array (you can C<push> to it
721	before or after loading AnyEvent), then they will called directly after	986	before or after loading AnyEvent), then they will be called directly
722	the event loop has been chosen.	987	after the event loop has been chosen.
723		988
724	You should check C<$AnyEvent::MODEL> before adding to this array, though:	989	You should check C<$AnyEvent::MODEL> before adding to this array, though:
725	if it contains a true value then the event loop has already been detected,	990	if it is defined then the event loop has already been detected, and the
726	and the array will be ignored.	991	array will be ignored.
727		992
728	Best use C<AnyEvent::post_detect { BLOCK }> instead.	993	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
		994	it, as it takes care of these details.
		995
		996	This variable is mainly useful for modules that can do something useful
		997	when AnyEvent is used and thus want to know when it is initialised, but do
		998	not need to even load it by default. This array provides the means to hook
		999	into AnyEvent passively, without loading it.
		1000
		1001	Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used
		1002	together, you could put this into Coro (this is the actual code used by
		1003	Coro to accomplish this):
		1004
		1005	if (defined $AnyEvent::MODEL) {
		1006	# AnyEvent already initialised, so load Coro::AnyEvent
		1007	require Coro::AnyEvent;
		1008	} else {
		1009	# AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
		1010	# as soon as it is
		1011	push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
		1012	}
		1013
		1014	=item AnyEvent::postpone { BLOCK }
		1015
		1016	Arranges for the block to be executed as soon as possible, but not before
		1017	the call itself returns. In practise, the block will be executed just
		1018	before the event loop polls for new events, or shortly afterwards.
		1019
		1020	This function never returns anything (to make the C<return postpone { ...
		1021	}> idiom more useful.
		1022
		1023	To understand the usefulness of this function, consider a function that
		1024	asynchronously does something for you and returns some transaction
		1025	object or guard to let you cancel the operation. For example,
		1026	C<AnyEvent::Socket::tcp_connect>:
		1027
		1028	# start a conenction attempt unless one is active
		1029	$self->{connect_guard} ||= AnyEvent::Socket::tcp_connect "www.example.net", 80, sub {
		1030	delete $self->{connect_guard};
		1031	...
		1032	};
		1033
		1034	Imagine that this function could instantly call the callback, for
		1035	example, because it detects an obvious error such as a negative port
		1036	number. Invoking the callback before the function returns causes problems
		1037	however: the callback will be called and will try to delete the guard
		1038	object. But since the function hasn't returned yet, there is nothing to
		1039	delete. When the function eventually returns it will assign the guard
		1040	object to C<< $self->{connect_guard} >>, where it will likely never be
		1041	deleted, so the program thinks it is still trying to connect.
		1042
		1043	This is where C<AnyEvent::postpone> should be used. Instead of calling the
		1044	callback directly on error:
		1045
		1046	$cb->(undef), return # signal error to callback, BAD!
		1047	if $some_error_condition;
		1048
		1049	It should use C<postpone>:
		1050
		1051	AnyEvent::postpone { $cb->(undef) }, return # signal error to callback, later
		1052	if $some_error_condition;
		1053
		1054	=item AnyEvent::log $level, $msg[, @args]
		1055
		1056	Log the given C<$msg> at the given C<$level>.
		1057
		1058	Loads AnyEvent::Log on first use and calls C<AnyEvent::Log::log> -
		1059	consequently, look at the L<AnyEvent::Log> documentation for details.
729		1060
730	=back	1061	=back
731		1062
732	=head1 WHAT TO DO IN A MODULE	1063	=head1 WHAT TO DO IN A MODULE
733		1064
…		…
744	because it will stall the whole program, and the whole point of using	1075	because it will stall the whole program, and the whole point of using
745	events is to stay interactive.	1076	events is to stay interactive.
746		1077
747	It is fine, however, to call C<< ->recv >> when the user of your module	1078	It is fine, however, to call C<< ->recv >> when the user of your module
748	requests it (i.e. if you create a http request object ad have a method	1079	requests it (i.e. if you create a http request object ad have a method
749	called C<results> that returns the results, it should call C<< ->recv >>	1080	called C<results> that returns the results, it may call C<< ->recv >>
750	freely, as the user of your module knows what she is doing. always).	1081	freely, as the user of your module knows what she is doing. Always).
751		1082
752	=head1 WHAT TO DO IN THE MAIN PROGRAM	1083	=head1 WHAT TO DO IN THE MAIN PROGRAM
753		1084
754	There will always be a single main program - the only place that should	1085	There will always be a single main program - the only place that should
755	dictate which event model to use.	1086	dictate which event model to use.
756		1087
757	If it doesn't care, it can just "use AnyEvent" and use it itself, or not	1088	If the program is not event-based, it need not do anything special, even
758	do anything special (it does not need to be event-based) and let AnyEvent	1089	when it depends on a module that uses an AnyEvent. If the program itself
759	decide which implementation to chose if some module relies on it.	1090	uses AnyEvent, but does not care which event loop is used, all it needs
		1091	to do is C<use AnyEvent>. In either case, AnyEvent will choose the best
		1092	available loop implementation.
760		1093
761	If the main program relies on a specific event model - for example, in	1094	If the main program relies on a specific event model - for example, in
762	Gtk2 programs you have to rely on the Glib module - you should load the	1095	Gtk2 programs you have to rely on the Glib module - you should load the
763	event module before loading AnyEvent or any module that uses it: generally	1096	event module before loading AnyEvent or any module that uses it: generally
764	speaking, you should load it as early as possible. The reason is that	1097	speaking, you should load it as early as possible. The reason is that
765	modules might create watchers when they are loaded, and AnyEvent will	1098	modules might create watchers when they are loaded, and AnyEvent will
766	decide on the event model to use as soon as it creates watchers, and it	1099	decide on the event model to use as soon as it creates watchers, and it
767	might chose the wrong one unless you load the correct one yourself.	1100	might choose the wrong one unless you load the correct one yourself.
768		1101
769	You can chose to use a pure-perl implementation by loading the	1102	You can chose to use a pure-perl implementation by loading the
770	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour	1103	C<AnyEvent::Loop> module, which gives you similar behaviour
771	everywhere, but letting AnyEvent chose the model is generally better.	1104	everywhere, but letting AnyEvent chose the model is generally better.
772		1105
773	=head2 MAINLOOP EMULATION	1106	=head2 MAINLOOP EMULATION
774		1107
775	Sometimes (often for short test scripts, or even standalone programs who	1108	Sometimes (often for short test scripts, or even standalone programs who
…		…
788		1121
789		1122
790	=head1 OTHER MODULES	1123	=head1 OTHER MODULES
791		1124
792	The following is a non-exhaustive list of additional modules that use	1125	The following is a non-exhaustive list of additional modules that use
793	AnyEvent and can therefore be mixed easily with other AnyEvent modules	1126	AnyEvent as a client and can therefore be mixed easily with other AnyEvent
794	in the same program. Some of the modules come with AnyEvent, some are	1127	modules and other event loops in the same program. Some of the modules
795	available via CPAN.	1128	come as part of AnyEvent, the others are available via CPAN.
796		1129
797	=over 4	1130	=over 4
798		1131
799	=item L<AnyEvent::Util>	1132	=item L<AnyEvent::Util>
800		1133
801	Contains various utility functions that replace often-used but blocking	1134	Contains various utility functions that replace often-used blocking
802	functions such as C<inet_aton> by event-/callback-based versions.	1135	functions such as C<inet_aton> with event/callback-based versions.
803		1136
804	=item L<AnyEvent::Socket>	1137	=item L<AnyEvent::Socket>
805		1138
806	Provides various utility functions for (internet protocol) sockets,	1139	Provides various utility functions for (internet protocol) sockets,
807	addresses and name resolution. Also functions to create non-blocking tcp	1140	addresses and name resolution. Also functions to create non-blocking tcp
…		…
809		1142
810	=item L<AnyEvent::Handle>	1143	=item L<AnyEvent::Handle>
811		1144
812	Provide read and write buffers, manages watchers for reads and writes,	1145	Provide read and write buffers, manages watchers for reads and writes,
813	supports raw and formatted I/O, I/O queued and fully transparent and	1146	supports raw and formatted I/O, I/O queued and fully transparent and
814	non-blocking SSL/TLS.	1147	non-blocking SSL/TLS (via L<AnyEvent::TLS>).
815		1148
816	=item L<AnyEvent::DNS>	1149	=item L<AnyEvent::DNS>
817		1150
818	Provides rich asynchronous DNS resolver capabilities.	1151	Provides rich asynchronous DNS resolver capabilities.
819		1152
		1153	=item L<AnyEvent::HTTP>, L<AnyEvent::IRC>, L<AnyEvent::XMPP>, L<AnyEvent::GPSD>, L<AnyEvent::IGS>, L<AnyEvent::FCP>
		1154
		1155	Implement event-based interfaces to the protocols of the same name (for
		1156	the curious, IGS is the International Go Server and FCP is the Freenet
		1157	Client Protocol).
		1158
		1159	=item L<AnyEvent::Handle::UDP>
		1160
		1161	Here be danger!
		1162
		1163	As Pauli would put it, "Not only is it not right, it's not even wrong!" -
		1164	there are so many things wrong with AnyEvent::Handle::UDP, most notably
		1165	its use of a stream-based API with a protocol that isn't streamable, that
		1166	the only way to improve it is to delete it.
		1167
		1168	It features data corruption (but typically only under load) and general
		1169	confusion. On top, the author is not only clueless about UDP but also
		1170	fact-resistant - some gems of his understanding: "connect doesn't work
		1171	with UDP", "UDP packets are not IP packets", "UDP only has datagrams, not
		1172	packets", "I don't need to implement proper error checking as UDP doesn't
		1173	support error checking" and so on - he doesn't even understand what's
		1174	wrong with his module when it is explained to him.
		1175
820	=item L<AnyEvent::HTTP>	1176	=item L<AnyEvent::DBI>
821		1177
822	A simple-to-use HTTP library that is capable of making a lot of concurrent	1178	Executes L<DBI> requests asynchronously in a proxy process for you,
823	HTTP requests.	1179	notifying you in an event-based way when the operation is finished.
		1180
		1181	=item L<AnyEvent::AIO>
		1182
		1183	Truly asynchronous (as opposed to non-blocking) I/O, should be in the
		1184	toolbox of every event programmer. AnyEvent::AIO transparently fuses
		1185	L<IO::AIO> and AnyEvent together, giving AnyEvent access to event-based
		1186	file I/O, and much more.
824		1187
825	=item L<AnyEvent::HTTPD>	1188	=item L<AnyEvent::HTTPD>
826		1189
827	Provides a simple web application server framework.	1190	A simple embedded webserver.
828		1191
829	=item L<AnyEvent::FastPing>	1192	=item L<AnyEvent::FastPing>
830		1193
831	The fastest ping in the west.	1194	The fastest ping in the west.
832		1195
833	=item L<AnyEvent::DBI>
834
835	Executes L<DBI> requests asynchronously in a proxy process.
836
837	=item L<AnyEvent::AIO>
838
839	Truly asynchronous I/O, should be in the toolbox of every event
840	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
841	together.
842
843	=item L<AnyEvent::BDB>
844
845	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
846	L<BDB> and AnyEvent together.
847
848	=item L<AnyEvent::GPSD>
849
850	A non-blocking interface to gpsd, a daemon delivering GPS information.
851
852	=item L<AnyEvent::IGS>
853
854	A non-blocking interface to the Internet Go Server protocol (used by
855	L<App::IGS>).
856
857	=item L<AnyEvent::IRC>
858
859	AnyEvent based IRC client module family (replacing the older Net::IRC3).
860
861	=item L<Net::XMPP2>
862
863	AnyEvent based XMPP (Jabber protocol) module family.
864
865	=item L<Net::FCP>
866
867	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
868	of AnyEvent.
869
870	=item L<Event::ExecFlow>
871
872	High level API for event-based execution flow control.
873
874	=item L<Coro>	1196	=item L<Coro>
875		1197
876	Has special support for AnyEvent via L<Coro::AnyEvent>.	1198	Has special support for AnyEvent via L<Coro::AnyEvent>.
877		1199
878	=item L<IO::Lambda>
879
880	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
881
882	=back	1200	=back
883		1201
884	=cut	1202	=cut
885		1203
886	package AnyEvent;	1204	package AnyEvent;
887		1205
888	no warnings;	1206	# basically a tuned-down version of common::sense
889	use strict qw(vars subs);	1207	sub common_sense {
		1208	# from common:.sense 3.4
		1209	${^WARNING_BITS} ^= ${^WARNING_BITS} ^ "\x3c\x3f\x33\x00\x0f\xf0\x0f\xc0\xf0\xfc\x33\x00";
		1210	# use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)
		1211	$^H |= 0x00000600;
		1212	}
890		1213
		1214	BEGIN { AnyEvent::common_sense }
		1215
891	use Carp;	1216	use Carp ();
892		1217
893	our $VERSION = 4.351;	1218	our $VERSION = '6.01';
894	our $MODEL;	1219	our $MODEL;
895		1220
896	our $AUTOLOAD;
897	our @ISA;	1221	our @ISA;
898		1222
899	our @REGISTRY;	1223	our @REGISTRY;
900		1224
901	our $WIN32;	1225	our $VERBOSE;
902		1226
903	BEGIN {	1227	BEGIN {
904	my $win32 = ! ! ($^O =~ /mswin32/i);	1228	require "AnyEvent/constants.pl";
905	eval "sub WIN32(){ $win32 }";
906	}
907		1229
		1230	eval "sub TAINT (){" . (${^TAINT}*1) . "}";
		1231
		1232	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
		1233	if ${^TAINT};
		1234
908	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1235	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
		1236	}
		1237
		1238	our $MAX_SIGNAL_LATENCY = 10;
909		1239
910	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred	1240	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
911		1241
912	{	1242	{
913	my $idx;	1243	my $idx;
914	$PROTOCOL{$_} = ++$idx	1244	$PROTOCOL{$_} = ++$idx
915	for reverse split /\s*,\s*/,	1245	for reverse split /\s*,\s*/,
916	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1246	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
917	}	1247	}
918		1248
		1249	our @post_detect;
		1250
		1251	sub post_detect(&) {
		1252	my ($cb) = @_;
		1253
		1254	push @post_detect, $cb;
		1255
		1256	defined wantarray
		1257	? bless \$cb, "AnyEvent::Util::postdetect"
		1258	: ()
		1259	}
		1260
		1261	sub AnyEvent::Util::postdetect::DESTROY {
		1262	@post_detect = grep $_ != ${$_[0]}, @post_detect;
		1263	}
		1264
		1265	our $POSTPONE_W;
		1266	our @POSTPONE;
		1267
		1268	sub _postpone_exec {
		1269	undef $POSTPONE_W;
		1270
		1271	&{ shift @POSTPONE }
		1272	while @POSTPONE;
		1273	}
		1274
		1275	sub postpone(&) {
		1276	push @POSTPONE, shift;
		1277
		1278	$POSTPONE_W ||= AE::timer (0, 0, \&_postpone_exec);
		1279
		1280	()
		1281	}
		1282
		1283	sub log($$;@) {
		1284	require AnyEvent::Log;
		1285	# AnyEvent::Log overwrites this function
		1286	goto &log;
		1287	}
		1288
919	my @models = (	1289	our @models = (
920	[EV:: => AnyEvent::Impl::EV::],	1290	[EV:: => AnyEvent::Impl::EV:: , 1],
921	[Event:: => AnyEvent::Impl::Event::],	1291	[AnyEvent::Loop:: => AnyEvent::Impl::Perl:: , 1],
922	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
923	# everything below here will not be autoprobed	1292	# everything below here will not (normally) be autoprobed
924	# as the pureperl backend should work everywhere	1293	# as the pure perl backend should work everywhere
925	# and is usually faster	1294	# and is usually faster
		1295	[Event:: => AnyEvent::Impl::Event::, 1],
		1296	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
		1297	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
		1298	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
926	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1299	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
927	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
928	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
929	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1300	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
930	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1301	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
931	[Wx:: => AnyEvent::Impl::POE::],	1302	[Wx:: => AnyEvent::Impl::POE::],
932	[Prima:: => AnyEvent::Impl::POE::],	1303	[Prima:: => AnyEvent::Impl::POE::],
		1304	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # a bitch to autodetect
		1305	[Cocoa::EventLoop:: => AnyEvent::Impl::Cocoa::],
		1306	[FLTK:: => AnyEvent::Impl::FLTK2::],
933	);	1307	);
934		1308
935	our %method = map +($_ => 1),	1309	our @isa_hook;
936	qw(io timer time now now_update signal child condvar one_event DESTROY);
937		1310
938	our @post_detect;	1311	sub _isa_set {
		1312	my @pkg = ("AnyEvent", (map $_->[0], grep defined, @isa_hook), $MODEL);
939		1313
		1314	@{"$pkg[$_-1]::ISA"} = $pkg[$_]
		1315	for 1 .. $#pkg;
		1316
		1317	grep $_ && $_->[1], @isa_hook
		1318	and AE::_reset ();
		1319	}
		1320
		1321	# used for hooking AnyEvent::Strict and AnyEvent::Debug::Wrap into the class hierarchy
		1322	sub _isa_hook($$;$) {
		1323	my ($i, $pkg, $reset_ae) = @_;
		1324
		1325	$isa_hook[$i] = $pkg ? [$pkg, $reset_ae] : undef;
		1326
		1327	_isa_set;
		1328	}
		1329
		1330	# all autoloaded methods reserve the complete glob, not just the method slot.
		1331	# due to bugs in perls method cache implementation.
		1332	our @methods = qw(io timer time now now_update signal child idle condvar);
		1333
940	sub post_detect(&) {	1334	sub detect() {
941	my ($cb) = @_;	1335	return $MODEL if $MODEL; # some programs keep references to detect
942		1336
943	if ($MODEL) {	1337	local $!; # for good measure
944	$cb->();	1338	local $SIG{__DIE__}; # we use eval
945		1339
946	1	1340	# free some memory
		1341	*detect = sub () { $MODEL };
		1342	# undef &func doesn't correctly update the method cache. grmbl.
		1343	# so we delete the whole glob. grmbl.
		1344	# otoh, perl doesn't let me undef an active usb, but it lets me free
		1345	# a glob with an active sub. hrm. i hope it works, but perl is
		1346	# usually buggy in this department. sigh.
		1347	delete @{"AnyEvent::"}{@methods};
		1348	undef @methods;
		1349
		1350	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z0-9:]+)$/) {
		1351	my $model = $1;
		1352	$model = "AnyEvent::Impl::$model" unless $model =~ s/::$//;
		1353	if (eval "require $model") {
		1354	$MODEL = $model;
		1355	AnyEvent::log 7 => "loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it."
		1356	if $VERBOSE >= 7;
947	} else {	1357	} else {
948	push @post_detect, $cb;	1358	AnyEvent::log warn => "unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@";
949		1359	}
950	defined wantarray
951	? bless \$cb, "AnyEvent::Util::PostDetect"
952	: ()
953	}	1360	}
954	}
955		1361
956	sub AnyEvent::Util::PostDetect::DESTROY {	1362	# check for already loaded models
957	@post_detect = grep $_ != ${$_[0]}, @post_detect;
958	}
959
960	sub detect() {
961	unless ($MODEL) {	1363	unless ($MODEL) {
962	no strict 'refs';	1364	for (@REGISTRY, @models) {
963	local $SIG{__DIE__};	1365	my ($package, $model) = @$_;
964		1366	if (${"$package\::VERSION"} > 0) {
965	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
966	my $model = "AnyEvent::Impl::$1";
967	if (eval "require $model") {	1367	if (eval "require $model") {
968	$MODEL = $model;	1368	$MODEL = $model;
969	warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1;	1369	AnyEvent::log 7 => "autodetected model '$model', using it."
970	} else {	1370	if $VERBOSE >= 7;
971	warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose;	1371	last;
		1372	}
972	}	1373	}
973	}	1374	}
974		1375
975	# check for already loaded models
976	unless ($MODEL) {	1376	unless ($MODEL) {
		1377	# try to autoload a model
977	for (@REGISTRY, @models) {	1378	for (@REGISTRY, @models) {
978	my ($package, $model) = @$_;	1379	my ($package, $model, $autoload) = @$_;
		1380	if (
		1381	$autoload
		1382	and eval "require $package"
979	if (${"$package\::VERSION"} > 0) {	1383	and ${"$package\::VERSION"} > 0
980	if (eval "require $model") {	1384	and eval "require $model"
		1385	) {
981	$MODEL = $model;	1386	$MODEL = $model;
982	warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1;	1387	AnyEvent::log 7 => "autoloaded model '$model', using it."
		1388	if $VERBOSE >= 7;
983	last;	1389	last;
984	}
985	}	1390	}
986	}	1391	}
987		1392
988	unless ($MODEL) {
989	# try to load a model
990
991	for (@REGISTRY, @models) {
992	my ($package, $model) = @$_;
993	if (eval "require $package"
994	and ${"$package\::VERSION"} > 0
995	and eval "require $model") {
996	$MODEL = $model;
997	warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1;
998	last;
999	}
1000	}
1001
1002	$MODEL	1393	$MODEL
1003	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";	1394	or die "AnyEvent: backend autodetection failed - did you properly install AnyEvent?";
1004	}
1005	}	1395	}
1006
1007	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1008
1009	unshift @ISA, $MODEL;
1010
1011	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
1012
1013	(shift @post_detect)->() while @post_detect;
1014	}	1396	}
1015		1397
		1398	# free memory only needed for probing
		1399	undef @models;
		1400	undef @REGISTRY;
		1401
		1402	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1403
		1404	# now nuke some methods that are overridden by the backend.
		1405	# SUPER usage is not allowed in these.
		1406	for (qw(time signal child idle)) {
		1407	undef &{"AnyEvent::Base::$_"}
		1408	if defined &{"$MODEL\::$_"};
		1409	}
		1410
		1411	_isa_set;
		1412
		1413	if ($ENV{PERL_ANYEVENT_STRICT}) {
		1414	require AnyEvent::Strict;
		1415	}
		1416
		1417	if ($ENV{PERL_ANYEVENT_DEBUG_WRAP}) {
		1418	require AnyEvent::Debug;
		1419	AnyEvent::Debug::wrap ($ENV{PERL_ANYEVENT_DEBUG_WRAP});
		1420	}
		1421
		1422	if (exists $ENV{PERL_ANYEVENT_DEBUG_SHELL}) {
		1423	require AnyEvent::Socket;
		1424	require AnyEvent::Debug;
		1425
		1426	my $shell = $ENV{PERL_ANYEVENT_DEBUG_SHELL};
		1427	$shell =~ s/\$\$/$$/g;
		1428
		1429	my ($host, $service) = AnyEvent::Socket::parse_hostport ($shell);
		1430	$AnyEvent::Debug::SHELL = AnyEvent::Debug::shell ($host, $service);
		1431	}
		1432
		1433	(shift @post_detect)->() while @post_detect;
		1434	undef @post_detect;
		1435
		1436	*post_detect = sub(&) {
		1437	shift->();
		1438
		1439	undef
		1440	};
		1441
1016	$MODEL	1442	$MODEL
1017	}	1443	}
1018		1444
1019	sub AUTOLOAD {	1445	for my $name (@methods) {
1020	(my $func = $AUTOLOAD) =~ s/.*://;	1446	*$name = sub {
1021		1447	detect;
1022	$method{$func}	1448	# we use goto because
1023	or croak "$func: not a valid method for AnyEvent objects";	1449	# a) it makes the thunk more transparent
1024		1450	# b) it allows us to delete the thunk later
1025	detect unless $MODEL;	1451	goto &{ UNIVERSAL::can AnyEvent => "SUPER::$name" }
1026		1452	};
1027	my $class = shift;
1028	$class->$func (@_);
1029	}	1453	}
1030		1454
1031	# utility function to dup a filehandle. this is used by many backends	1455	# utility function to dup a filehandle. this is used by many backends
1032	# to support binding more than one watcher per filehandle (they usually	1456	# to support binding more than one watcher per filehandle (they usually
1033	# allow only one watcher per fd, so we dup it to get a different one).	1457	# allow only one watcher per fd, so we dup it to get a different one).
1034	sub _dupfh($$$$) {	1458	sub _dupfh($$;$$) {
1035	my ($poll, $fh, $r, $w) = @_;	1459	my ($poll, $fh, $r, $w) = @_;
1036		1460
1037	# cygwin requires the fh mode to be matching, unix doesn't	1461	# cygwin requires the fh mode to be matching, unix doesn't
1038	my ($rw, $mode) = $poll eq "r" ? ($r, "<")	1462	my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1039	: $poll eq "w" ? ($w, ">")
1040	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1041		1463
1042	open my $fh2, "$mode&" . fileno $fh	1464	open my $fh2, $mode, $fh
1043	or die "cannot dup() filehandle: $!,";	1465	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1044		1466
1045	# we assume CLOEXEC is already set by perl in all important cases	1467	# we assume CLOEXEC is already set by perl in all important cases
1046		1468
1047	($fh2, $rw)	1469	($fh2, $rw)
1048	}	1470	}
1049		1471
		1472	=head1 SIMPLIFIED AE API
		1473
		1474	Starting with version 5.0, AnyEvent officially supports a second, much
		1475	simpler, API that is designed to reduce the calling, typing and memory
		1476	overhead by using function call syntax and a fixed number of parameters.
		1477
		1478	See the L<AE> manpage for details.
		1479
		1480	=cut
		1481
		1482	package AE;
		1483
		1484	our $VERSION = $AnyEvent::VERSION;
		1485
		1486	sub _reset() {
		1487	eval q{
		1488	# fall back to the main API by default - backends and AnyEvent::Base
		1489	# implementations can overwrite these.
		1490
		1491	sub io($$$) {
		1492	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
		1493	}
		1494
		1495	sub timer($$$) {
		1496	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
		1497	}
		1498
		1499	sub signal($$) {
		1500	AnyEvent->signal (signal => $_[0], cb => $_[1])
		1501	}
		1502
		1503	sub child($$) {
		1504	AnyEvent->child (pid => $_[0], cb => $_[1])
		1505	}
		1506
		1507	sub idle($) {
		1508	AnyEvent->idle (cb => $_[0]);
		1509	}
		1510
		1511	sub cv(;&) {
		1512	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
		1513	}
		1514
		1515	sub now() {
		1516	AnyEvent->now
		1517	}
		1518
		1519	sub now_update() {
		1520	AnyEvent->now_update
		1521	}
		1522
		1523	sub time() {
		1524	AnyEvent->time
		1525	}
		1526
		1527	*postpone = \&AnyEvent::postpone;
		1528	*log = \&AnyEvent::log;
		1529	};
		1530	die if $@;
		1531	}
		1532
		1533	BEGIN { _reset }
		1534
1050	package AnyEvent::Base;	1535	package AnyEvent::Base;
1051		1536
1052	# default implementations for many methods	1537	# default implementations for many methods
1053		1538
1054	BEGIN {	1539	sub time {
		1540	eval q{ # poor man's autoloading {}
		1541	# probe for availability of Time::HiRes
1055	if (eval "use Time::HiRes (); time (); 1") {	1542	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1543	AnyEvent::log 8 => "AnyEvent: using Time::HiRes for sub-second timing accuracy."
		1544	if $AnyEvent::VERBOSE >= 8;
		1545	*time = sub { Time::HiRes::time () };
1056	*_time = \&Time::HiRes::time;	1546	*AE::time = \& Time::HiRes::time ;
1057	# if (eval "use POSIX (); (POSIX::times())...	1547	# if (eval "use POSIX (); (POSIX::times())...
1058	} else {	1548	} else {
1059	*_time = sub { time }; # epic fail	1549	AnyEvent::log critical => "using built-in time(), WARNING, no sub-second resolution!";
		1550	*time = sub { CORE::time };
		1551	*AE::time = sub (){ CORE::time };
		1552	}
		1553
		1554	*now = \&time;
		1555	};
		1556	die if $@;
		1557
		1558	&time
		1559	}
		1560
		1561	*now = \&time;
		1562	sub now_update { }
		1563
		1564	sub _poll {
		1565	Carp::croak "$AnyEvent::MODEL does not support blocking waits. Caught";
		1566	}
		1567
		1568	# default implementation for ->condvar
		1569	# in fact, the default should not be overwritten
		1570
		1571	sub condvar {
		1572	eval q{ # poor man's autoloading {}
		1573	*condvar = sub {
		1574	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
		1575	};
		1576
		1577	*AE::cv = sub (;&) {
		1578	bless { @_ ? (_ae_cb => shift) : () }, "AnyEvent::CondVar"
		1579	};
		1580	};
		1581	die if $@;
		1582
		1583	&condvar
		1584	}
		1585
		1586	# default implementation for ->signal
		1587
		1588	our $HAVE_ASYNC_INTERRUPT;
		1589
		1590	sub _have_async_interrupt() {
		1591	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
		1592	&& eval "use Async::Interrupt 1.02 (); 1")
		1593	unless defined $HAVE_ASYNC_INTERRUPT;
		1594
		1595	$HAVE_ASYNC_INTERRUPT
		1596	}
		1597
		1598	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1599	our (%SIG_ASY, %SIG_ASY_W);
		1600	our ($SIG_COUNT, $SIG_TW);
		1601
		1602	# install a dummy wakeup watcher to reduce signal catching latency
		1603	# used by Impls
		1604	sub _sig_add() {
		1605	unless ($SIG_COUNT++) {
		1606	# try to align timer on a full-second boundary, if possible
		1607	my $NOW = AE::now;
		1608
		1609	$SIG_TW = AE::timer
		1610	$MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
		1611	$MAX_SIGNAL_LATENCY,
		1612	sub { } # just for the PERL_ASYNC_CHECK
		1613	;
1060	}	1614	}
1061	}	1615	}
1062		1616
1063	sub time { _time }	1617	sub _sig_del {
1064	sub now { _time }	1618	undef $SIG_TW
1065	sub now_update { }	1619	unless --$SIG_COUNT;
1066
1067	# default implementation for ->condvar
1068
1069	sub condvar {
1070	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::
1071	}	1620	}
1072		1621
1073	# default implementation for ->signal	1622	our $_sig_name_init; $_sig_name_init = sub {
		1623	eval q{ # poor man's autoloading {}
		1624	undef $_sig_name_init;
1074		1625
1075	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1626	if (_have_async_interrupt) {
		1627	*sig2num = \&Async::Interrupt::sig2num;
		1628	*sig2name = \&Async::Interrupt::sig2name;
		1629	} else {
		1630	require Config;
1076		1631
1077	sub _signal_exec {	1632	my %signame2num;
1078	sysread $SIGPIPE_R, my $dummy, 4;	1633	@signame2num{ split ' ', $Config::Config{sig_name} }
		1634	= split ' ', $Config::Config{sig_num};
1079		1635
1080	while (%SIG_EV) {	1636	my @signum2name;
1081	for (keys %SIG_EV) {	1637	@signum2name[values %signame2num] = keys %signame2num;
1082	delete $SIG_EV{$_};	1638
1083	$_->() for values %{ $SIG_CB{$_} || {} };	1639	*sig2num = sub($) {
		1640	$_[0] > 0 ? shift : $signame2num{+shift}
		1641	};
		1642	*sig2name = sub ($) {
		1643	$_[0] > 0 ? $signum2name[+shift] : shift
		1644	};
1084	}	1645	}
1085	}	1646	};
1086	}	1647	die if $@;
		1648	};
		1649
		1650	sub sig2num ($) { &$_sig_name_init; &sig2num }
		1651	sub sig2name($) { &$_sig_name_init; &sig2name }
1087		1652
1088	sub signal {	1653	sub signal {
1089	my (undef, %arg) = @_;	1654	eval q{ # poor man's autoloading {}
		1655	# probe for availability of Async::Interrupt
		1656	if (_have_async_interrupt) {
		1657	AnyEvent::log 8 => "using Async::Interrupt for race-free signal handling."
		1658	if $AnyEvent::VERBOSE >= 8;
1090		1659
1091	unless ($SIGPIPE_R) {	1660	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1092	require Fcntl;	1661	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1093		1662
1094	if (AnyEvent::WIN32) {
1095	require AnyEvent::Util;
1096
1097	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1098	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1099	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1100	} else {	1663	} else {
		1664	AnyEvent::log 8 => "using emulated perl signal handling with latency timer."
		1665	if $AnyEvent::VERBOSE >= 8;
		1666
		1667	if (AnyEvent::WIN32) {
		1668	require AnyEvent::Util;
		1669
		1670	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1671	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
		1672	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
		1673	} else {
1101	pipe $SIGPIPE_R, $SIGPIPE_W;	1674	pipe $SIGPIPE_R, $SIGPIPE_W;
1102	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;	1675	fcntl $SIGPIPE_R, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_R;
1103	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case	1676	fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case
		1677
		1678	# not strictly required, as $^F is normally 2, but let's make sure...
		1679	fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
		1680	fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
		1681	}
		1682
		1683	$SIGPIPE_R
		1684	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1685
		1686	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
1104	}	1687	}
1105		1688
1106	$SIGPIPE_R	1689	*signal = $HAVE_ASYNC_INTERRUPT
1107	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";	1690	? sub {
		1691	my (undef, %arg) = @_;
1108		1692
1109	# not strictly required, as $^F is normally 2, but let's make sure...	1693	# async::interrupt
1110	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1111	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1112
1113	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1114	}
1115
1116	my $signal = uc $arg{signal}	1694	my $signal = sig2num $arg{signal};
1117	or Carp::croak "required option 'signal' is missing";
1118
1119	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1695	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1696
		1697	$SIG_ASY{$signal} ||= new Async::Interrupt
		1698	cb => sub { undef $SIG_EV{$signal} },
		1699	signal => $signal,
		1700	pipe => [$SIGPIPE_R->filenos],
		1701	pipe_autodrain => 0,
		1702	;
		1703
		1704	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1705	}
		1706	: sub {
		1707	my (undef, %arg) = @_;
		1708
		1709	# pure perl
		1710	my $signal = sig2name $arg{signal};
		1711	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1712
1120	$SIG{$signal} ||= sub {	1713	$SIG{$signal} ||= sub {
1121	local $!;	1714	local $!;
1122	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;	1715	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1123	undef $SIG_EV{$signal};	1716	undef $SIG_EV{$signal};
		1717	};
		1718
		1719	# can't do signal processing without introducing races in pure perl,
		1720	# so limit the signal latency.
		1721	_sig_add;
		1722
		1723	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1724	}
		1725	;
		1726
		1727	*AnyEvent::Base::signal::DESTROY = sub {
		1728	my ($signal, $cb) = @{$_[0]};
		1729
		1730	_sig_del;
		1731
		1732	delete $SIG_CB{$signal}{$cb};
		1733
		1734	$HAVE_ASYNC_INTERRUPT
		1735	? delete $SIG_ASY{$signal}
		1736	: # delete doesn't work with older perls - they then
		1737	# print weird messages, or just unconditionally exit
		1738	# instead of getting the default action.
		1739	undef $SIG{$signal}
		1740	unless keys %{ $SIG_CB{$signal} };
		1741	};
		1742
		1743	*_signal_exec = sub {
		1744	$HAVE_ASYNC_INTERRUPT
		1745	? $SIGPIPE_R->drain
		1746	: sysread $SIGPIPE_R, (my $dummy), 9;
		1747
		1748	while (%SIG_EV) {
		1749	for (keys %SIG_EV) {
		1750	delete $SIG_EV{$_};
		1751	&$_ for values %{ $SIG_CB{$_} || {} };
		1752	}
		1753	}
		1754	};
1124	};	1755	};
		1756	die if $@;
1125		1757
1126	bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"	1758	&signal
1127	}
1128
1129	sub AnyEvent::Base::Signal::DESTROY {
1130	my ($signal, $cb) = @{$_[0]};
1131
1132	delete $SIG_CB{$signal}{$cb};
1133
1134	delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
1135	}	1759	}
1136		1760
1137	# default implementation for ->child	1761	# default implementation for ->child
1138		1762
1139	our %PID_CB;	1763	our %PID_CB;
1140	our $CHLD_W;	1764	our $CHLD_W;
1141	our $CHLD_DELAY_W;	1765	our $CHLD_DELAY_W;
1142	our $PID_IDLE;
1143	our $WNOHANG;
1144		1766
1145	sub _child_wait {	1767	# used by many Impl's
1146	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1768	sub _emit_childstatus($$) {
		1769	my (undef, $rpid, $rstatus) = @_;
		1770
		1771	$_->($rpid, $rstatus)
1147	$_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),	1772	for values %{ $PID_CB{$rpid} || {} },
1148	(values %{ $PID_CB{0} || {} });	1773	values %{ $PID_CB{0} || {} };
1149	}
1150
1151	undef $PID_IDLE;
1152	}
1153
1154	sub _sigchld {
1155	# make sure we deliver these changes "synchronous" with the event loop.
1156	$CHLD_DELAY_W ||= AnyEvent->timer (after => 0, cb => sub {
1157	undef $CHLD_DELAY_W;
1158	&_child_wait;
1159	});
1160	}	1774	}
1161		1775
1162	sub child {	1776	sub child {
		1777	eval q{ # poor man's autoloading {}
		1778	*_sigchld = sub {
		1779	my $pid;
		1780
		1781	AnyEvent->_emit_childstatus ($pid, $?)
		1782	while ($pid = waitpid -1, WNOHANG) > 0;
		1783	};
		1784
		1785	*child = sub {
1163	my (undef, %arg) = @_;	1786	my (undef, %arg) = @_;
1164		1787
1165	defined (my $pid = $arg{pid} + 0)	1788	my $pid = $arg{pid};
1166	or Carp::croak "required option 'pid' is missing";	1789	my $cb = $arg{cb};
1167		1790
1168	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1791	$PID_CB{$pid}{$cb+0} = $cb;
1169		1792
1170	unless ($WNOHANG) {
1171	$WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1172	}
1173
1174	unless ($CHLD_W) {	1793	unless ($CHLD_W) {
1175	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1794	$CHLD_W = AE::signal CHLD => \&_sigchld;
1176	# child could be a zombie already, so make at least one round	1795	# child could be a zombie already, so make at least one round
1177	&_sigchld;	1796	&_sigchld;
1178	}	1797	}
1179		1798
1180	bless [$pid, $arg{cb}], "AnyEvent::Base::Child"	1799	bless [$pid, $cb+0], "AnyEvent::Base::child"
1181	}	1800	};
1182		1801
1183	sub AnyEvent::Base::Child::DESTROY {	1802	*AnyEvent::Base::child::DESTROY = sub {
1184	my ($pid, $cb) = @{$_[0]};	1803	my ($pid, $icb) = @{$_[0]};
1185		1804
1186	delete $PID_CB{$pid}{$cb};	1805	delete $PID_CB{$pid}{$icb};
1187	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1806	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1188		1807
1189	undef $CHLD_W unless keys %PID_CB;	1808	undef $CHLD_W unless keys %PID_CB;
		1809	};
		1810	};
		1811	die if $@;
		1812
		1813	&child
		1814	}
		1815
		1816	# idle emulation is done by simply using a timer, regardless
		1817	# of whether the process is idle or not, and not letting
		1818	# the callback use more than 50% of the time.
		1819	sub idle {
		1820	eval q{ # poor man's autoloading {}
		1821	*idle = sub {
		1822	my (undef, %arg) = @_;
		1823
		1824	my ($cb, $w, $rcb) = $arg{cb};
		1825
		1826	$rcb = sub {
		1827	if ($cb) {
		1828	$w = AE::time;
		1829	&$cb;
		1830	$w = AE::time - $w;
		1831
		1832	# never use more then 50% of the time for the idle watcher,
		1833	# within some limits
		1834	$w = 0.0001 if $w < 0.0001;
		1835	$w = 5 if $w > 5;
		1836
		1837	$w = AE::timer $w, 0, $rcb;
		1838	} else {
		1839	# clean up...
		1840	undef $w;
		1841	undef $rcb;
		1842	}
		1843	};
		1844
		1845	$w = AE::timer 0.05, 0, $rcb;
		1846
		1847	bless \\$cb, "AnyEvent::Base::idle"
		1848	};
		1849
		1850	*AnyEvent::Base::idle::DESTROY = sub {
		1851	undef $${$_[0]};
		1852	};
		1853	};
		1854	die if $@;
		1855
		1856	&idle
1190	}	1857	}
1191		1858
1192	package AnyEvent::CondVar;	1859	package AnyEvent::CondVar;
1193		1860
1194	our @ISA = AnyEvent::CondVar::Base::;	1861	our @ISA = AnyEvent::CondVar::Base::;
1195		1862
		1863	# only to be used for subclassing
		1864	sub new {
		1865	my $class = shift;
		1866	bless AnyEvent->condvar (@_), $class
		1867	}
		1868
1196	package AnyEvent::CondVar::Base;	1869	package AnyEvent::CondVar::Base;
1197		1870
1198	use overload	1871	#use overload
1199	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1872	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1200	fallback => 1;	1873	# fallback => 1;
		1874
		1875	# save 300+ kilobytes by dirtily hardcoding overloading
		1876	${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
		1877	*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
		1878	*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
		1879	${'AnyEvent::CondVar::Base::()'} = 1; # fallback
		1880
		1881	our $WAITING;
1201		1882
1202	sub _send {	1883	sub _send {
1203	# nop	1884	# nop
		1885	}
		1886
		1887	sub _wait {
		1888	AnyEvent->_poll until $_[0]{_ae_sent};
1204	}	1889	}
1205		1890
1206	sub send {	1891	sub send {
1207	my $cv = shift;	1892	my $cv = shift;
1208	$cv->{_ae_sent} = [@_];	1893	$cv->{_ae_sent} = [@_];
…		…
1217		1902
1218	sub ready {	1903	sub ready {
1219	$_[0]{_ae_sent}	1904	$_[0]{_ae_sent}
1220	}	1905	}
1221		1906
1222	sub _wait {
1223	AnyEvent->one_event while !$_[0]{_ae_sent};
1224	}
1225
1226	sub recv {	1907	sub recv {
		1908	unless ($_[0]{_ae_sent}) {
		1909	$WAITING
		1910	and Carp::croak "AnyEvent::CondVar: recursive blocking wait attempted";
		1911
		1912	local $WAITING = 1;
1227	$_[0]->_wait;	1913	$_[0]->_wait;
		1914	}
1228		1915
1229	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1916	$_[0]{_ae_croak}
1230	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1917	and Carp::croak $_[0]{_ae_croak};
		1918
		1919	wantarray
		1920	? @{ $_[0]{_ae_sent} }
		1921	: $_[0]{_ae_sent}[0]
1231	}	1922	}
1232		1923
1233	sub cb {	1924	sub cb {
1234	$_[0]{_ae_cb} = $_[1] if @_ > 1;	1925	my $cv = shift;
		1926
		1927	@_
		1928	and $cv->{_ae_cb} = shift
		1929	and $cv->{_ae_sent}
		1930	and (delete $cv->{_ae_cb})->($cv);
		1931
1235	$_[0]{_ae_cb}	1932	$cv->{_ae_cb}
1236	}	1933	}
1237		1934
1238	sub begin {	1935	sub begin {
1239	++$_[0]{_ae_counter};	1936	++$_[0]{_ae_counter};
1240	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;	1937	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
…		…
1245	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };	1942	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };
1246	}	1943	}
1247		1944
1248	# undocumented/compatibility with pre-3.4	1945	# undocumented/compatibility with pre-3.4
1249	*broadcast = \&send;	1946	*broadcast = \&send;
1250	*wait = \&_wait;	1947	*wait = \&recv;
1251		1948
1252	=head1 ERROR AND EXCEPTION HANDLING	1949	=head1 ERROR AND EXCEPTION HANDLING
1253		1950
1254	In general, AnyEvent does not do any error handling - it relies on the	1951	In general, AnyEvent does not do any error handling - it relies on the
1255	caller to do that if required. The L<AnyEvent::Strict> module (see also	1952	caller to do that if required. The L<AnyEvent::Strict> module (see also
…		…
1268	so on.	1965	so on.
1269		1966
1270	=head1 ENVIRONMENT VARIABLES	1967	=head1 ENVIRONMENT VARIABLES
1271		1968
1272	The following environment variables are used by this module or its	1969	The following environment variables are used by this module or its
1273	submodules:	1970	submodules.
		1971
		1972	Note that AnyEvent will remove I<all> environment variables starting with
		1973	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		1974	enabled.
1274		1975
1275	=over 4	1976	=over 4
1276		1977
1277	=item C<PERL_ANYEVENT_VERBOSE>	1978	=item C<PERL_ANYEVENT_VERBOSE>
1278		1979
1279	By default, AnyEvent will be completely silent except in fatal	1980	By default, AnyEvent will be completely silent except in fatal
1280	conditions. You can set this environment variable to make AnyEvent more	1981	conditions. You can set this environment variable to make AnyEvent more
1281	talkative.	1982	talkative.
1282		1983
1283	When set to C<1> or higher, causes AnyEvent to warn about unexpected	1984	When set to C<5> or higher, causes AnyEvent to warn about unexpected
1284	conditions, such as not being able to load the event model specified by	1985	conditions, such as not being able to load the event model specified by
1285	C<PERL_ANYEVENT_MODEL>.	1986	C<PERL_ANYEVENT_MODEL>.
1286		1987
1287	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	1988	When set to C<7> or higher, cause AnyEvent to report to STDERR which event
1288	model it chooses.	1989	model it chooses.
		1990
		1991	When set to C<8> or higher, then AnyEvent will report extra information on
		1992	which optional modules it loads and how it implements certain features.
1289		1993
1290	=item C<PERL_ANYEVENT_STRICT>	1994	=item C<PERL_ANYEVENT_STRICT>
1291		1995
1292	AnyEvent does not do much argument checking by default, as thorough	1996	AnyEvent does not do much argument checking by default, as thorough
1293	argument checking is very costly. Setting this variable to a true value	1997	argument checking is very costly. Setting this variable to a true value
1294	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly	1998	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1295	check the arguments passed to most method calls. If it finds any problems	1999	check the arguments passed to most method calls. If it finds any problems,
1296	it will croak.	2000	it will croak.
1297		2001
1298	In other words, enables "strict" mode.	2002	In other words, enables "strict" mode.
1299		2003
1300	Unlike C<use strict>, it is definitely recommended ot keep it off in	2004	Unlike C<use strict> (or its modern cousin, C<< use L<common::sense>
1301	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while	2005	>>, it is definitely recommended to keep it off in production. Keeping
1302	developing programs can be very useful, however.	2006	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
		2007	can be very useful, however.
		2008
		2009	=item C<PERL_ANYEVENT_DEBUG_SHELL>
		2010
		2011	If this env variable is set, then its contents will be interpreted by
		2012	C<AnyEvent::Socket::parse_hostport> (after replacing every occurance of
		2013	C<$$> by the process pid) and an C<AnyEvent::Debug::shell> is bound on
		2014	that port. The shell object is saved in C<$AnyEvent::Debug::SHELL>.
		2015
		2016	This takes place when the first watcher is created.
		2017
		2018	For example, to bind a debug shell on a unix domain socket in
		2019	F<< /tmp/debug<pid>.sock >>, you could use this:
		2020
		2021	PERL_ANYEVENT_DEBUG_SHELL=/tmp/debug\$\$.sock perlprog
		2022
		2023	Note that creating sockets in F</tmp> is very unsafe on multiuser
		2024	systems.
		2025
		2026	=item C<PERL_ANYEVENT_DEBUG_WRAP>
		2027
		2028	Can be set to C<0>, C<1> or C<2> and enables wrapping of all watchers for
		2029	debugging purposes. See C<AnyEvent::Debug::wrap> for details.
1303		2030
1304	=item C<PERL_ANYEVENT_MODEL>	2031	=item C<PERL_ANYEVENT_MODEL>
1305		2032
1306	This can be used to specify the event model to be used by AnyEvent, before	2033	This can be used to specify the event model to be used by AnyEvent, before
1307	auto detection and -probing kicks in. It must be a string consisting	2034	auto detection and -probing kicks in.
1308	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended	2035
		2036	It normally is a string consisting entirely of ASCII letters (e.g. C<EV>
		2037	or C<IOAsync>). The string C<AnyEvent::Impl::> gets prepended and the
1309	and the resulting module name is loaded and if the load was successful,	2038	resulting module name is loaded and - if the load was successful - used as
1310	used as event model. If it fails to load AnyEvent will proceed with	2039	event model backend. If it fails to load then AnyEvent will proceed with
1311	auto detection and -probing.	2040	auto detection and -probing.
1312		2041
1313	This functionality might change in future versions.	2042	If the string ends with C<::> instead (e.g. C<AnyEvent::Impl::EV::>) then
		2043	nothing gets prepended and the module name is used as-is (hint: C<::> at
		2044	the end of a string designates a module name and quotes it appropriately).
1314		2045
1315	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you	2046	For example, to force the pure perl model (L<AnyEvent::Loop::Perl>) you
1316	could start your program like this:	2047	could start your program like this:
1317		2048
1318	PERL_ANYEVENT_MODEL=Perl perl ...	2049	PERL_ANYEVENT_MODEL=Perl perl ...
1319		2050
1320	=item C<PERL_ANYEVENT_PROTOCOLS>	2051	=item C<PERL_ANYEVENT_PROTOCOLS>
…		…
1350		2081
1351	=item C<PERL_ANYEVENT_MAX_FORKS>	2082	=item C<PERL_ANYEVENT_MAX_FORKS>
1352		2083
1353	The maximum number of child processes that C<AnyEvent::Util::fork_call>	2084	The maximum number of child processes that C<AnyEvent::Util::fork_call>
1354	will create in parallel.	2085	will create in parallel.
		2086
		2087	=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
		2088
		2089	The default value for the C<max_outstanding> parameter for the default DNS
		2090	resolver - this is the maximum number of parallel DNS requests that are
		2091	sent to the DNS server.
		2092
		2093	=item C<PERL_ANYEVENT_RESOLV_CONF>
		2094
		2095	The file to use instead of F</etc/resolv.conf> (or OS-specific
		2096	configuration) in the default resolver. When set to the empty string, no
		2097	default config will be used.
		2098
		2099	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
		2100
		2101	When neither C<ca_file> nor C<ca_path> was specified during
		2102	L<AnyEvent::TLS> context creation, and either of these environment
		2103	variables exist, they will be used to specify CA certificate locations
		2104	instead of a system-dependent default.
		2105
		2106	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
		2107
		2108	When these are set to C<1>, then the respective modules are not
		2109	loaded. Mostly good for testing AnyEvent itself.
1355		2110
1356	=back	2111	=back
1357		2112
1358	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	2113	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1359		2114
…		…
1417	warn "read: $input\n"; # output what has been read	2172	warn "read: $input\n"; # output what has been read
1418	$cv->send if $input =~ /^q/i; # quit program if /^q/i	2173	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1419	},	2174	},
1420	);	2175	);
1421		2176
1422	my $time_watcher; # can only be used once
1423
1424	sub new_timer {
1425	$timer = AnyEvent->timer (after => 1, cb => sub {	2177	my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1426	warn "timeout\n"; # print 'timeout' about every second	2178	warn "timeout\n"; # print 'timeout' at most every second
1427	&new_timer; # and restart the time
1428	});	2179	});
1429	}
1430
1431	new_timer; # create first timer
1432		2180
1433	$cv->recv; # wait until user enters /^q/i	2181	$cv->recv; # wait until user enters /^q/i
1434		2182
1435	=head1 REAL-WORLD EXAMPLE	2183	=head1 REAL-WORLD EXAMPLE
1436		2184
…		…
1509		2257
1510	The actual code goes further and collects all errors (C<die>s, exceptions)	2258	The actual code goes further and collects all errors (C<die>s, exceptions)
1511	that occurred during request processing. The C<result> method detects	2259	that occurred during request processing. The C<result> method detects
1512	whether an exception as thrown (it is stored inside the $txn object)	2260	whether an exception as thrown (it is stored inside the $txn object)
1513	and just throws the exception, which means connection errors and other	2261	and just throws the exception, which means connection errors and other
1514	problems get reported tot he code that tries to use the result, not in a	2262	problems get reported to the code that tries to use the result, not in a
1515	random callback.	2263	random callback.
1516		2264
1517	All of this enables the following usage styles:	2265	All of this enables the following usage styles:
1518		2266
1519	1. Blocking:	2267	1. Blocking:
…		…
1567	through AnyEvent. The benchmark creates a lot of timers (with a zero	2315	through AnyEvent. The benchmark creates a lot of timers (with a zero
1568	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	2316	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1569	which it is), lets them fire exactly once and destroys them again.	2317	which it is), lets them fire exactly once and destroys them again.
1570		2318
1571	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	2319	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1572	distribution.	2320	distribution. It uses the L<AE> interface, which makes a real difference
		2321	for the EV and Perl backends only.
1573		2322
1574	=head3 Explanation of the columns	2323	=head3 Explanation of the columns
1575		2324
1576	I<watcher> is the number of event watchers created/destroyed. Since	2325	I<watcher> is the number of event watchers created/destroyed. Since
1577	different event models feature vastly different performances, each event	2326	different event models feature vastly different performances, each event
…		…
1598	watcher.	2347	watcher.
1599		2348
1600	=head3 Results	2349	=head3 Results
1601		2350
1602	name watchers bytes create invoke destroy comment	2351	name watchers bytes create invoke destroy comment
1603	EV/EV 400000 224 0.47 0.35 0.27 EV native interface	2352	EV/EV 100000 223 0.47 0.43 0.27 EV native interface
1604	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	2353	EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
1605	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal	2354	Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
1606	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation	2355	Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
1607	Event/Event 16000 517 32.20 31.80 0.81 Event native interface	2356	Event/Event 16000 516 31.16 31.84 0.82 Event native interface
1608	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers	2357	Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
		2358	IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
		2359	IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
1609	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour	2360	Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
1610	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers	2361	Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
1611	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event	2362	POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
1612	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select	2363	POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
1613		2364
1614	=head3 Discussion	2365	=head3 Discussion
1615		2366
1616	The benchmark does I<not> measure scalability of the event loop very	2367	The benchmark does I<not> measure scalability of the event loop very
1617	well. For example, a select-based event loop (such as the pure perl one)	2368	well. For example, a select-based event loop (such as the pure perl one)
…		…
1629	benchmark machine, handling an event takes roughly 1600 CPU cycles with	2380	benchmark machine, handling an event takes roughly 1600 CPU cycles with
1630	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU	2381	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
1631	cycles with POE.	2382	cycles with POE.
1632		2383
1633	C<EV> is the sole leader regarding speed and memory use, which are both	2384	C<EV> is the sole leader regarding speed and memory use, which are both
1634	maximal/minimal, respectively. Even when going through AnyEvent, it uses	2385	maximal/minimal, respectively. When using the L<AE> API there is zero
		2386	overhead (when going through the AnyEvent API create is about 5-6 times
		2387	slower, with other times being equal, so still uses far less memory than
1635	far less memory than any other event loop and is still faster than Event	2388	any other event loop and is still faster than Event natively).
1636	natively.
1637		2389
1638	The pure perl implementation is hit in a few sweet spots (both the	2390	The pure perl implementation is hit in a few sweet spots (both the
1639	constant timeout and the use of a single fd hit optimisations in the perl	2391	constant timeout and the use of a single fd hit optimisations in the perl
1640	interpreter and the backend itself). Nevertheless this shows that it	2392	interpreter and the backend itself). Nevertheless this shows that it
1641	adds very little overhead in itself. Like any select-based backend its	2393	adds very little overhead in itself. Like any select-based backend its
1642	performance becomes really bad with lots of file descriptors (and few of	2394	performance becomes really bad with lots of file descriptors (and few of
1643	them active), of course, but this was not subject of this benchmark.	2395	them active), of course, but this was not subject of this benchmark.
1644		2396
1645	The C<Event> module has a relatively high setup and callback invocation	2397	The C<Event> module has a relatively high setup and callback invocation
1646	cost, but overall scores in on the third place.	2398	cost, but overall scores in on the third place.
		2399
		2400	C<IO::Async> performs admirably well, about on par with C<Event>, even
		2401	when using its pure perl backend.
1647		2402
1648	C<Glib>'s memory usage is quite a bit higher, but it features a	2403	C<Glib>'s memory usage is quite a bit higher, but it features a
1649	faster callback invocation and overall ends up in the same class as	2404	faster callback invocation and overall ends up in the same class as
1650	C<Event>. However, Glib scales extremely badly, doubling the number of	2405	C<Event>. However, Glib scales extremely badly, doubling the number of
1651	watchers increases the processing time by more than a factor of four,	2406	watchers increases the processing time by more than a factor of four,
…		…
1686	(even when used without AnyEvent), but most event loops have acceptable	2441	(even when used without AnyEvent), but most event loops have acceptable
1687	performance with or without AnyEvent.	2442	performance with or without AnyEvent.
1688		2443
1689	=item * The overhead AnyEvent adds is usually much smaller than the overhead of	2444	=item * The overhead AnyEvent adds is usually much smaller than the overhead of
1690	the actual event loop, only with extremely fast event loops such as EV	2445	the actual event loop, only with extremely fast event loops such as EV
1691	adds AnyEvent significant overhead.	2446	does AnyEvent add significant overhead.
1692		2447
1693	=item * You should avoid POE like the plague if you want performance or	2448	=item * You should avoid POE like the plague if you want performance or
1694	reasonable memory usage.	2449	reasonable memory usage.
1695		2450
1696	=back	2451	=back
…		…
1712	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100	2467	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1713	(1%) are active. This mirrors the activity of large servers with many	2468	(1%) are active. This mirrors the activity of large servers with many
1714	connections, most of which are idle at any one point in time.	2469	connections, most of which are idle at any one point in time.
1715		2470
1716	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	2471	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1717	distribution.	2472	distribution. It uses the L<AE> interface, which makes a real difference
		2473	for the EV and Perl backends only.
1718		2474
1719	=head3 Explanation of the columns	2475	=head3 Explanation of the columns
1720		2476
1721	I<sockets> is the number of sockets, and twice the number of "servers" (as	2477	I<sockets> is the number of sockets, and twice the number of "servers" (as
1722	each server has a read and write socket end).	2478	each server has a read and write socket end).
…		…
1729	it to another server. This includes deleting the old timeout and creating	2485	it to another server. This includes deleting the old timeout and creating
1730	a new one that moves the timeout into the future.	2486	a new one that moves the timeout into the future.
1731		2487
1732	=head3 Results	2488	=head3 Results
1733		2489
1734	name sockets create request	2490	name sockets create request
1735	EV 20000 69.01 11.16	2491	EV 20000 62.66 7.99
1736	Perl 20000 73.32 35.87	2492	Perl 20000 68.32 32.64
1737	Event 20000 212.62 257.32	2493	IOAsync 20000 174.06 101.15 epoll
1738	Glib 20000 651.16 1896.30	2494	IOAsync 20000 174.67 610.84 poll
		2495	Event 20000 202.69 242.91
		2496	Glib 20000 557.01 1689.52
1739	POE 20000 349.67 12317.24 uses POE::Loop::Event	2497	POE 20000 341.54 12086.32 uses POE::Loop::Event
1740		2498
1741	=head3 Discussion	2499	=head3 Discussion
1742		2500
1743	This benchmark I<does> measure scalability and overall performance of the	2501	This benchmark I<does> measure scalability and overall performance of the
1744	particular event loop.	2502	particular event loop.
…		…
1746	EV is again fastest. Since it is using epoll on my system, the setup time	2504	EV is again fastest. Since it is using epoll on my system, the setup time
1747	is relatively high, though.	2505	is relatively high, though.
1748		2506
1749	Perl surprisingly comes second. It is much faster than the C-based event	2507	Perl surprisingly comes second. It is much faster than the C-based event
1750	loops Event and Glib.	2508	loops Event and Glib.
		2509
		2510	IO::Async performs very well when using its epoll backend, and still quite
		2511	good compared to Glib when using its pure perl backend.
1751		2512
1752	Event suffers from high setup time as well (look at its code and you will	2513	Event suffers from high setup time as well (look at its code and you will
1753	understand why). Callback invocation also has a high overhead compared to	2514	understand why). Callback invocation also has a high overhead compared to
1754	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event	2515	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
1755	uses select or poll in basically all documented configurations.	2516	uses select or poll in basically all documented configurations.
…		…
1818	=item * C-based event loops perform very well with small number of	2579	=item * C-based event loops perform very well with small number of
1819	watchers, as the management overhead dominates.	2580	watchers, as the management overhead dominates.
1820		2581
1821	=back	2582	=back
1822		2583
		2584	=head2 THE IO::Lambda BENCHMARK
		2585
		2586	Recently I was told about the benchmark in the IO::Lambda manpage, which
		2587	could be misinterpreted to make AnyEvent look bad. In fact, the benchmark
		2588	simply compares IO::Lambda with POE, and IO::Lambda looks better (which
		2589	shouldn't come as a surprise to anybody). As such, the benchmark is
		2590	fine, and mostly shows that the AnyEvent backend from IO::Lambda isn't
		2591	very optimal. But how would AnyEvent compare when used without the extra
		2592	baggage? To explore this, I wrote the equivalent benchmark for AnyEvent.
		2593
		2594	The benchmark itself creates an echo-server, and then, for 500 times,
		2595	connects to the echo server, sends a line, waits for the reply, and then
		2596	creates the next connection. This is a rather bad benchmark, as it doesn't
		2597	test the efficiency of the framework or much non-blocking I/O, but it is a
		2598	benchmark nevertheless.
		2599
		2600	name runtime
		2601	Lambda/select 0.330 sec
		2602	+ optimized 0.122 sec
		2603	Lambda/AnyEvent 0.327 sec
		2604	+ optimized 0.138 sec
		2605	Raw sockets/select 0.077 sec
		2606	POE/select, components 0.662 sec
		2607	POE/select, raw sockets 0.226 sec
		2608	POE/select, optimized 0.404 sec
		2609
		2610	AnyEvent/select/nb 0.085 sec
		2611	AnyEvent/EV/nb 0.068 sec
		2612	+state machine 0.134 sec
		2613
		2614	The benchmark is also a bit unfair (my fault): the IO::Lambda/POE
		2615	benchmarks actually make blocking connects and use 100% blocking I/O,
		2616	defeating the purpose of an event-based solution. All of the newly
		2617	written AnyEvent benchmarks use 100% non-blocking connects (using
		2618	AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS
		2619	resolver), so AnyEvent is at a disadvantage here, as non-blocking connects
		2620	generally require a lot more bookkeeping and event handling than blocking
		2621	connects (which involve a single syscall only).
		2622
		2623	The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which
		2624	offers similar expressive power as POE and IO::Lambda, using conventional
		2625	Perl syntax. This means that both the echo server and the client are 100%
		2626	non-blocking, further placing it at a disadvantage.
		2627
		2628	As you can see, the AnyEvent + EV combination even beats the
		2629	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
		2630	backend easily beats IO::Lambda and POE.
		2631
		2632	And even the 100% non-blocking version written using the high-level (and
		2633	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
		2634	higher level ("unoptimised") abstractions by a large margin, even though
		2635	it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
		2636
		2637	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
		2638	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
		2639	part of the IO::Lambda distribution and were used without any changes.
		2640
1823		2641
1824	=head1 SIGNALS	2642	=head1 SIGNALS
1825		2643
1826	AnyEvent currently installs handlers for these signals:	2644	AnyEvent currently installs handlers for these signals:
1827		2645
…		…
1830	=item SIGCHLD	2648	=item SIGCHLD
1831		2649
1832	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher	2650	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
1833	emulation for event loops that do not support them natively. Also, some	2651	emulation for event loops that do not support them natively. Also, some
1834	event loops install a similar handler.	2652	event loops install a similar handler.
		2653
		2654	Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
		2655	AnyEvent will reset it to default, to avoid losing child exit statuses.
1835		2656
1836	=item SIGPIPE	2657	=item SIGPIPE
1837		2658
1838	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>	2659	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
1839	when AnyEvent gets loaded.	2660	when AnyEvent gets loaded.
…		…
1851		2672
1852	=back	2673	=back
1853		2674
1854	=cut	2675	=cut
1855		2676
		2677	undef $SIG{CHLD}
		2678	if $SIG{CHLD} eq 'IGNORE';
		2679
1856	$SIG{PIPE} = sub { }	2680	$SIG{PIPE} = sub { }
1857	unless defined $SIG{PIPE};	2681	unless defined $SIG{PIPE};
1858		2682
		2683	=head1 RECOMMENDED/OPTIONAL MODULES
		2684
		2685	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
		2686	its built-in modules) are required to use it.
		2687
		2688	That does not mean that AnyEvent won't take advantage of some additional
		2689	modules if they are installed.
		2690
		2691	This section explains which additional modules will be used, and how they
		2692	affect AnyEvent's operation.
		2693
		2694	=over 4
		2695
		2696	=item L<Async::Interrupt>
		2697
		2698	This slightly arcane module is used to implement fast signal handling: To
		2699	my knowledge, there is no way to do completely race-free and quick
		2700	signal handling in pure perl. To ensure that signals still get
		2701	delivered, AnyEvent will start an interval timer to wake up perl (and
		2702	catch the signals) with some delay (default is 10 seconds, look for
		2703	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
		2704
		2705	If this module is available, then it will be used to implement signal
		2706	catching, which means that signals will not be delayed, and the event loop
		2707	will not be interrupted regularly, which is more efficient (and good for
		2708	battery life on laptops).
		2709
		2710	This affects not just the pure-perl event loop, but also other event loops
		2711	that have no signal handling on their own (e.g. Glib, Tk, Qt).
		2712
		2713	Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
		2714	and either employ their own workarounds (POE) or use AnyEvent's workaround
		2715	(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
		2716	does nothing for those backends.
		2717
		2718	=item L<EV>
		2719
		2720	This module isn't really "optional", as it is simply one of the backend
		2721	event loops that AnyEvent can use. However, it is simply the best event
		2722	loop available in terms of features, speed and stability: It supports
		2723	the AnyEvent API optimally, implements all the watcher types in XS, does
		2724	automatic timer adjustments even when no monotonic clock is available,
		2725	can take avdantage of advanced kernel interfaces such as C<epoll> and
		2726	C<kqueue>, and is the fastest backend I<by far>. You can even embed
		2727	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
		2728
		2729	If you only use backends that rely on another event loop (e.g. C<Tk>),
		2730	then this module will do nothing for you.
		2731
		2732	=item L<Guard>
		2733
		2734	The guard module, when used, will be used to implement
		2735	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
		2736	lot less memory), but otherwise doesn't affect guard operation much. It is
		2737	purely used for performance.
		2738
		2739	=item L<JSON> and L<JSON::XS>
		2740
		2741	One of these modules is required when you want to read or write JSON data
		2742	via L<AnyEvent::Handle>. L<JSON> is also written in pure-perl, but can take
		2743	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
		2744
		2745	=item L<Net::SSLeay>
		2746
		2747	Implementing TLS/SSL in Perl is certainly interesting, but not very
		2748	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
		2749	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
		2750
		2751	=item L<Time::HiRes>
		2752
		2753	This module is part of perl since release 5.008. It will be used when the
		2754	chosen event library does not come with a timing source of its own. The
		2755	pure-perl event loop (L<AnyEvent::Loop>) will additionally load it to
		2756	try to use a monotonic clock for timing stability.
		2757
		2758	=back
		2759
1859		2760
1860	=head1 FORK	2761	=head1 FORK
1861		2762
1862	Most event libraries are not fork-safe. The ones who are usually are	2763	Most event libraries are not fork-safe. The ones who are usually are
1863	because they rely on inefficient but fork-safe C<select> or C<poll>	2764	because they rely on inefficient but fork-safe C<select> or C<poll> calls
1864	calls. Only L<EV> is fully fork-aware.	2765	- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
		2766	are usually badly thought-out hacks that are incompatible with fork in
		2767	one way or another. Only L<EV> is fully fork-aware and ensures that you
		2768	continue event-processing in both parent and child (or both, if you know
		2769	what you are doing).
		2770
		2771	This means that, in general, you cannot fork and do event processing in
		2772	the child if the event library was initialised before the fork (which
		2773	usually happens when the first AnyEvent watcher is created, or the library
		2774	is loaded).
1865		2775
1866	If you have to fork, you must either do so I<before> creating your first	2776	If you have to fork, you must either do so I<before> creating your first
1867	watcher OR you must not use AnyEvent at all in the child.	2777	watcher OR you must not use AnyEvent at all in the child OR you must do
		2778	something completely out of the scope of AnyEvent.
		2779
		2780	The problem of doing event processing in the parent I<and> the child
		2781	is much more complicated: even for backends that I<are> fork-aware or
		2782	fork-safe, their behaviour is not usually what you want: fork clones all
		2783	watchers, that means all timers, I/O watchers etc. are active in both
		2784	parent and child, which is almost never what you want. USing C<exec>
		2785	to start worker children from some kind of manage rprocess is usually
		2786	preferred, because it is much easier and cleaner, at the expense of having
		2787	to have another binary.
1868		2788
1869		2789
1870	=head1 SECURITY CONSIDERATIONS	2790	=head1 SECURITY CONSIDERATIONS
1871		2791
1872	AnyEvent can be forced to load any event model via	2792	AnyEvent can be forced to load any event model via
…		…
1884	use AnyEvent;	2804	use AnyEvent;
1885		2805
1886	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	2806	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1887	be used to probe what backend is used and gain other information (which is	2807	be used to probe what backend is used and gain other information (which is
1888	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and	2808	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
1889	$ENV{PERL_ANYEGENT_STRICT}.	2809	$ENV{PERL_ANYEVENT_STRICT}.
		2810
		2811	Note that AnyEvent will remove I<all> environment variables starting with
		2812	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		2813	enabled.
1890		2814
1891		2815
1892	=head1 BUGS	2816	=head1 BUGS
1893		2817
1894	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard	2818	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
…		…
1898	pronounced).	2822	pronounced).
1899		2823
1900		2824
1901	=head1 SEE ALSO	2825	=head1 SEE ALSO
1902		2826
1903	Utility functions: L<AnyEvent::Util>.	2827	Tutorial/Introduction: L<AnyEvent::Intro>.
1904		2828
1905	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,	2829	FAQ: L<AnyEvent::FAQ>.
1906	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2830
		2831	Utility functions: L<AnyEvent::Util> (misc. grab-bag), L<AnyEvent::Log>
		2832	(simply logging).
		2833
		2834	Development/Debugging: L<AnyEvent::Strict> (stricter checking),
		2835	L<AnyEvent::Debug> (interactive shell, watcher tracing).
		2836
		2837	Supported event modules: L<AnyEvent::Loop>, L<EV>, L<EV::Glib>,
		2838	L<Glib::EV>, L<Event>, L<Glib::Event>, L<Glib>, L<Tk>, L<Event::Lib>,
		2839	L<Qt>, L<POE>, L<FLTK>.
1907		2840
1908	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2841	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1909	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2842	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1910	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2843	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
		2844	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>,
1911	L<AnyEvent::Impl::POE>.	2845	L<AnyEvent::Impl::FLTK>.
1912		2846
1913	Non-blocking file handles, sockets, TCP clients and	2847	Non-blocking handles, pipes, stream sockets, TCP clients and
1914	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.	2848	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
1915		2849
1916	Asynchronous DNS: L<AnyEvent::DNS>.	2850	Asynchronous DNS: L<AnyEvent::DNS>.
1917		2851
1918	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,	2852	Thread support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>.
1919		2853
1920	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.	2854	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::IRC>,
		2855	L<AnyEvent::HTTP>.
1921		2856
1922		2857
1923	=head1 AUTHOR	2858	=head1 AUTHOR
1924		2859
1925	Marc Lehmann <schmorp@schmorp.de>	2860	Marc Lehmann <schmorp@schmorp.de>

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