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Revision 1.382 by root, Thu Sep 1 23:46:26 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 and POE are various supported	5	EV, Event, Glib, Tk, Perl, Event::Lib, Irssi, rxvt-unicode, IO::Async, Qt,
6	event loops.	6	FLTK and POE are various supported event loops/environments.
7		7
8	=head1 SYNOPSIS	8	=head1 SYNOPSIS
9		9
10	use AnyEvent;	10	use AnyEvent;
11		11
		12	# if you prefer function calls, look at the AE manpage for
		13	# an alternative API.
		14
12	# file descriptor readable	15	# file handle or descriptor readable
13	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });	16	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });
14		17
15	# one-shot or repeating timers	18	# one-shot or repeating timers
16	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });	19	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
17	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...	20	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...);
18		21
19	print AnyEvent->now; # prints current event loop time	22	print AnyEvent->now; # prints current event loop time
20	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.	23	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
21		24
22	# POSIX signal	25	# POSIX signal
…		…
40	=head1 INTRODUCTION/TUTORIAL	43	=head1 INTRODUCTION/TUTORIAL
41		44
42	This manpage is mainly a reference manual. If you are interested	45	This manpage is mainly a reference manual. If you are interested
43	in a tutorial or some gentle introduction, have a look at the	46	in a tutorial or some gentle introduction, have a look at the
44	L<AnyEvent::Intro> manpage.	47	L<AnyEvent::Intro> manpage.
		48
		49	=head1 SUPPORT
		50
		51	An FAQ document is available as L<AnyEvent::FAQ>.
		52
		53	There also is a mailinglist for discussing all things AnyEvent, and an IRC
		54	channel, too.
		55
		56	See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software
		57	Repository>, at L<http://anyevent.schmorp.de>, for more info.
45		58
46	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)	59	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
47		60
48	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen	61	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
49	nowadays. So what is different about AnyEvent?	62	nowadays. So what is different about AnyEvent?
…		…
65	module users into the same thing by forcing them to use the same event	78	module users into the same thing by forcing them to use the same event
66	model you use.	79	model you use.
67		80
68	For modules like POE or IO::Async (which is a total misnomer as it is	81	For modules like POE or IO::Async (which is a total misnomer as it is
69	actually doing all I/O I<synchronously>...), using them in your module is	82	actually doing all I/O I<synchronously>...), using them in your module is
70	like joining a cult: After you joined, you are dependent on them and you	83	like joining a cult: After you join, you are dependent on them and you
71	cannot use anything else, as they are simply incompatible to everything	84	cannot use anything else, as they are simply incompatible to everything
72	that isn't them. What's worse, all the potential users of your	85	that isn't them. What's worse, all the potential users of your
73	module are I<also> forced to use the same event loop you use.	86	module are I<also> forced to use the same event loop you use.
74		87
75	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works	88	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
76	fine. AnyEvent + Tk works fine etc. etc. but none of these work together	89	fine. AnyEvent + Tk works fine etc. etc. but none of these work together
77	with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if	90	with the rest: POE + EV? No go. Tk + Event? No go. Again: if your module
78	your module uses one of those, every user of your module has to use it,	91	uses one of those, every user of your module has to use it, too. But if
79	too. But if your module uses AnyEvent, it works transparently with all	92	your module uses AnyEvent, it works transparently with all event models it
80	event models it supports (including stuff like IO::Async, as long as those	93	supports (including stuff like IO::Async, as long as those use one of the
81	use one of the supported event loops. It is trivial to add new event loops	94	supported event loops. It is easy to add new event loops to AnyEvent, too,
82	to AnyEvent, too, so it is future-proof).	95	so it is future-proof).
83		96
84	In addition to being free of having to use I<the one and only true event	97	In addition to being free of having to use I<the one and only true event
85	model>, AnyEvent also is free of bloat and policy: with POE or similar	98	model>, AnyEvent also is free of bloat and policy: with POE or similar
86	modules, you get an enormous amount of code and strict rules you have to	99	modules, you get an enormous amount of code and strict rules you have to
87	follow. AnyEvent, on the other hand, is lean and up to the point, by only	100	follow. AnyEvent, on the other hand, is lean and to the point, by only
88	offering the functionality that is necessary, in as thin as a wrapper as	101	offering the functionality that is necessary, in as thin as a wrapper as
89	technically possible.	102	technically possible.
90		103
91	Of course, AnyEvent comes with a big (and fully optional!) toolbox	104	Of course, AnyEvent comes with a big (and fully optional!) toolbox
92	of useful functionality, such as an asynchronous DNS resolver, 100%	105	of useful functionality, such as an asynchronous DNS resolver, 100%
…		…
98	useful) and you want to force your users to use the one and only event	111	useful) and you want to force your users to use the one and only event
99	model, you should I<not> use this module.	112	model, you should I<not> use this module.
100		113
101	=head1 DESCRIPTION	114	=head1 DESCRIPTION
102		115
103	L<AnyEvent> provides an identical interface to multiple event loops. This	116	L<AnyEvent> provides a uniform interface to various event loops. This
104	allows module authors to utilise an event loop without forcing module	117	allows module authors to use event loop functionality without forcing
105	users to use the same event loop (as only a single event loop can coexist	118	module users to use a specific event loop implementation (since more
106	peacefully at any one time).	119	than one event loop cannot coexist peacefully).
107		120
108	The interface itself is vaguely similar, but not identical to the L<Event>	121	The interface itself is vaguely similar, but not identical to the L<Event>
109	module.	122	module.
110		123
111	During the first call of any watcher-creation method, the module tries	124	During the first call of any watcher-creation method, the module tries
112	to detect the currently loaded event loop by probing whether one of the	125	to detect the currently loaded event loop by probing whether one of the
113	following modules is already loaded: L<EV>,	126	following modules is already loaded: L<EV>, L<AnyEvent::Loop>,
114	L<Event>, L<Glib>, L<AnyEvent::Impl::Perl>, L<Tk>, L<Event::Lib>, L<Qt>,	127	L<Event>, L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. The first one
115	L<POE>. The first one found is used. If none are found, the module tries	128	found is used. If none are detected, the module tries to load the first
116	to load these modules (excluding Tk, Event::Lib, Qt and POE as the pure perl	129	four modules in the order given; but note that if L<EV> is not
117	adaptor should always succeed) in the order given. The first one that can	130	available, the pure-perl L<AnyEvent::Loop> should always work, so
118	be successfully loaded will be used. If, after this, still none could be	131	the other two are not normally tried.
119	found, AnyEvent will fall back to a pure-perl event loop, which is not
120	very efficient, but should work everywhere.
121		132
122	Because AnyEvent first checks for modules that are already loaded, loading	133	Because AnyEvent first checks for modules that are already loaded, loading
123	an event model explicitly before first using AnyEvent will likely make	134	an event model explicitly before first using AnyEvent will likely make
124	that model the default. For example:	135	that model the default. For example:
125		136
…		…
127	use AnyEvent;	138	use AnyEvent;
128		139
129	# .. AnyEvent will likely default to Tk	140	# .. AnyEvent will likely default to Tk
130		141
131	The I<likely> means that, if any module loads another event model and	142	The I<likely> means that, if any module loads another event model and
132	starts using it, all bets are off. Maybe you should tell their authors to	143	starts using it, all bets are off - this case should be very rare though,
133	use AnyEvent so their modules work together with others seamlessly...	144	as very few modules hardcode event loops without announcing this very
		145	loudly.
134		146
135	The pure-perl implementation of AnyEvent is called	147	The pure-perl implementation of AnyEvent is called C<AnyEvent::Loop>. Like
136	C<AnyEvent::Impl::Perl>. Like other event modules you can load it	148	other event modules you can load it explicitly and enjoy the high
137	explicitly and enjoy the high availability of that event loop :)	149	availability of that event loop :)
138		150
139	=head1 WATCHERS	151	=head1 WATCHERS
140		152
141	AnyEvent has the central concept of a I<watcher>, which is an object that	153	AnyEvent has the central concept of a I<watcher>, which is an object that
142	stores relevant data for each kind of event you are waiting for, such as	154	stores relevant data for each kind of event you are waiting for, such as
…		…
147	callback when the event occurs (of course, only when the event model	159	callback when the event occurs (of course, only when the event model
148	is in control).	160	is in control).
149		161
150	Note that B<callbacks must not permanently change global variables>	162	Note that B<callbacks must not permanently change global variables>
151	potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<	163	potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<
152	callbacks must not C<die> >>. The former is good programming practise in	164	callbacks must not C<die> >>. The former is good programming practice in
153	Perl and the latter stems from the fact that exception handling differs	165	Perl and the latter stems from the fact that exception handling differs
154	widely between event loops.	166	widely between event loops.
155		167
156	To disable the watcher you have to destroy it (e.g. by setting the	168	To disable a watcher you have to destroy it (e.g. by setting the
157	variable you store it in to C<undef> or otherwise deleting all references	169	variable you store it in to C<undef> or otherwise deleting all references
158	to it).	170	to it).
159		171
160	All watchers are created by calling a method on the C<AnyEvent> class.	172	All watchers are created by calling a method on the C<AnyEvent> class.
161		173
162	Many watchers either are used with "recursion" (repeating timers for	174	Many watchers either are used with "recursion" (repeating timers for
163	example), or need to refer to their watcher object in other ways.	175	example), or need to refer to their watcher object in other ways.
164		176
165	An any way to achieve that is this pattern:	177	One way to achieve that is this pattern:
166		178
167	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {	179	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
168	# you can use $w here, for example to undef it	180	# you can use $w here, for example to undef it
169	undef $w;	181	undef $w;
170	});	182	});
…		…
173	my variables are only visible after the statement in which they are	185	my variables are only visible after the statement in which they are
174	declared.	186	declared.
175		187
176	=head2 I/O WATCHERS	188	=head2 I/O WATCHERS
177		189
		190	$w = AnyEvent->io (
		191	fh => <filehandle_or_fileno>,
		192	poll => <"r" or "w">,
		193	cb => <callback>,
		194	);
		195
178	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	196	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
179	with the following mandatory key-value pairs as arguments:	197	with the following mandatory key-value pairs as arguments:
180		198
181	C<fh> is the Perl I<file handle> (I<not> file descriptor) to watch	199	C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch
182	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
183	handle). Note that only file handles pointing to things for which	201	handle). Note that only file handles pointing to things for which
184	non-blocking operation makes sense are allowed. This includes sockets,	202	non-blocking operation makes sense are allowed. This includes sockets,
185	most character devices, pipes, fifos and so on, but not for example files	203	most character devices, pipes, fifos and so on, but not for example files
186	or block devices.	204	or block devices.
…		…
196		214
197	The I/O watcher might use the underlying file descriptor or a copy of it.	215	The I/O watcher might use the underlying file descriptor or a copy of it.
198	You must not close a file handle as long as any watcher is active on the	216	You must not close a file handle as long as any watcher is active on the
199	underlying file descriptor.	217	underlying file descriptor.
200		218
201	Some event loops issue spurious readyness notifications, so you should	219	Some event loops issue spurious readiness notifications, so you should
202	always use non-blocking calls when reading/writing from/to your file	220	always use non-blocking calls when reading/writing from/to your file
203	handles.	221	handles.
204		222
205	Example: wait for readability of STDIN, then read a line and disable the	223	Example: wait for readability of STDIN, then read a line and disable the
206	watcher.	224	watcher.
…		…
211	undef $w;	229	undef $w;
212	});	230	});
213		231
214	=head2 TIME WATCHERS	232	=head2 TIME WATCHERS
215		233
		234	$w = AnyEvent->timer (after => <seconds>, cb => <callback>);
		235
		236	$w = AnyEvent->timer (
		237	after => <fractional_seconds>,
		238	interval => <fractional_seconds>,
		239	cb => <callback>,
		240	);
		241
216	You can create a time watcher by calling the C<< AnyEvent->timer >>	242	You can create a time watcher by calling the C<< AnyEvent->timer >>
217	method with the following mandatory arguments:	243	method with the following mandatory arguments:
218		244
219	C<after> specifies after how many seconds (fractional values are	245	C<after> specifies after how many seconds (fractional values are
220	supported) the callback should be invoked. C<cb> is the callback to invoke	246	supported) the callback should be invoked. C<cb> is the callback to invoke
…		…
222		248
223	Although the callback might get passed parameters, their value and	249	Although the callback might get passed parameters, their value and
224	presence is undefined and you cannot rely on them. Portable AnyEvent	250	presence is undefined and you cannot rely on them. Portable AnyEvent
225	callbacks cannot use arguments passed to time watcher callbacks.	251	callbacks cannot use arguments passed to time watcher callbacks.
226		252
227	The callback will normally be invoked once only. If you specify another	253	The callback will normally be invoked only once. If you specify another
228	parameter, C<interval>, as a strictly positive number (> 0), then the	254	parameter, C<interval>, as a strictly positive number (> 0), then the
229	callback will be invoked regularly at that interval (in fractional	255	callback will be invoked regularly at that interval (in fractional
230	seconds) after the first invocation. If C<interval> is specified with a	256	seconds) after the first invocation. If C<interval> is specified with a
231	false value, then it is treated as if it were missing.	257	false value, then it is treated as if it were not specified at all.
232		258
233	The callback will be rescheduled before invoking the callback, but no	259	The callback will be rescheduled before invoking the callback, but no
234	attempt is done to avoid timer drift in most backends, so the interval is	260	attempt is made to avoid timer drift in most backends, so the interval is
235	only approximate.	261	only approximate.
236		262
237	Example: fire an event after 7.7 seconds.	263	Example: fire an event after 7.7 seconds.
238		264
239	my $w = AnyEvent->timer (after => 7.7, cb => sub {	265	my $w = AnyEvent->timer (after => 7.7, cb => sub {
…		…
257		283
258	While most event loops expect timers to specified in a relative way, they	284	While most event loops expect timers to specified in a relative way, they
259	use absolute time internally. This makes a difference when your clock	285	use absolute time internally. This makes a difference when your clock
260	"jumps", for example, when ntp decides to set your clock backwards from	286	"jumps", for example, when ntp decides to set your clock backwards from
261	the wrong date of 2014-01-01 to 2008-01-01, a watcher that is supposed to	287	the wrong date of 2014-01-01 to 2008-01-01, a watcher that is supposed to
262	fire "after" a second might actually take six years to finally fire.	288	fire "after a second" might actually take six years to finally fire.
263		289
264	AnyEvent cannot compensate for this. The only event loop that is conscious	290	AnyEvent cannot compensate for this. The only event loop that is conscious
265	about these issues is L<EV>, which offers both relative (ev_timer, based	291	of these issues is L<EV>, which offers both relative (ev_timer, based
266	on true relative time) and absolute (ev_periodic, based on wallclock time)	292	on true relative time) and absolute (ev_periodic, based on wallclock time)
267	timers.	293	timers.
268		294
269	AnyEvent always prefers relative timers, if available, matching the	295	AnyEvent always prefers relative timers, if available, matching the
270	AnyEvent API.	296	AnyEvent API.
…		…
292	I<In almost all cases (in all cases if you don't care), this is the	318	I<In almost all cases (in all cases if you don't care), this is the
293	function to call when you want to know the current time.>	319	function to call when you want to know the current time.>
294		320
295	This function is also often faster then C<< AnyEvent->time >>, and	321	This function is also often faster then C<< AnyEvent->time >>, and
296	thus the preferred method if you want some timestamp (for example,	322	thus the preferred method if you want some timestamp (for example,
297	L<AnyEvent::Handle> uses this to update it's activity timeouts).	323	L<AnyEvent::Handle> uses this to update its activity timeouts).
298		324
299	The rest of this section is only of relevance if you try to be very exact	325	The rest of this section is only of relevance if you try to be very exact
300	with your timing, you can skip it without bad conscience.	326	with your timing; you can skip it without a bad conscience.
301		327
302	For a practical example of when these times differ, consider L<Event::Lib>	328	For a practical example of when these times differ, consider L<Event::Lib>
303	and L<EV> and the following set-up:	329	and L<EV> and the following set-up:
304		330
305	The event loop is running and has just invoked one of your callback at	331	The event loop is running and has just invoked one of your callbacks at
306	time=500 (assume no other callbacks delay processing). In your callback,	332	time=500 (assume no other callbacks delay processing). In your callback,
307	you wait a second by executing C<sleep 1> (blocking the process for a	333	you wait a second by executing C<sleep 1> (blocking the process for a
308	second) and then (at time=501) you create a relative timer that fires	334	second) and then (at time=501) you create a relative timer that fires
309	after three seconds.	335	after three seconds.
310		336
…		…
330	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into	356	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
331	account.	357	account.
332		358
333	=item AnyEvent->now_update	359	=item AnyEvent->now_update
334		360
335	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
336	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 >>,
337	AnyEvent->now >>, above).	363	above).
338		364
339	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
340	this "current" time will differ substantially from the real time, which	366	this "current" time will differ substantially from the real time, which
341	might affect timers and time-outs.	367	might affect timers and time-outs.
342		368
343	When this is the case, you can call this method, which will update the	369	When this is the case, you can call this method, which will update the
344	event loop's idea of "current time".	370	event loop's idea of "current time".
345		371
		372	A typical example would be a script in a web server (e.g. C<mod_perl>) -
		373	when mod_perl executes the script, then the event loop will have the wrong
		374	idea about the "current time" (being potentially far in the past, when the
		375	script ran the last time). In that case you should arrange a call to C<<
		376	AnyEvent->now_update >> each time the web server process wakes up again
		377	(e.g. at the start of your script, or in a handler).
		378
346	Note that updating the time I<might> cause some events to be handled.	379	Note that updating the time I<might> cause some events to be handled.
347		380
348	=back	381	=back
349		382
350	=head2 SIGNAL WATCHERS	383	=head2 SIGNAL WATCHERS
		384
		385	$w = AnyEvent->signal (signal => <uppercase_signal_name>, cb => <callback>);
351		386
352	You can watch for signals using a signal watcher, C<signal> is the signal	387	You can watch for signals using a signal watcher, C<signal> is the signal
353	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl	388	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
354	callback to be invoked whenever a signal occurs.	389	callback to be invoked whenever a signal occurs.
355		390
…		…
361	invocation, and callback invocation will be synchronous. Synchronous means	396	invocation, and callback invocation will be synchronous. Synchronous means
362	that it might take a while until the signal gets handled by the process,	397	that it might take a while until the signal gets handled by the process,
363	but it is guaranteed not to interrupt any other callbacks.	398	but it is guaranteed not to interrupt any other callbacks.
364		399
365	The main advantage of using these watchers is that you can share a signal	400	The main advantage of using these watchers is that you can share a signal
366	between multiple watchers.	401	between multiple watchers, and AnyEvent will ensure that signals will not
		402	interrupt your program at bad times.
367		403
368	This watcher might use C<%SIG>, so programs overwriting those signals	404	This watcher might use C<%SIG> (depending on the event loop used),
369	directly will likely not work correctly.	405	so programs overwriting those signals directly will likely not work
		406	correctly.
370		407
371	Example: exit on SIGINT	408	Example: exit on SIGINT
372		409
373	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });	410	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
374		411
		412	=head3 Restart Behaviour
		413
		414	While restart behaviour is up to the event loop implementation, most will
		415	not restart syscalls (that includes L<Async::Interrupt> and AnyEvent's
		416	pure perl implementation).
		417
		418	=head3 Safe/Unsafe Signals
		419
		420	Perl signals can be either "safe" (synchronous to opcode handling) or
		421	"unsafe" (asynchronous) - the former might get delayed indefinitely, the
		422	latter might corrupt your memory.
		423
		424	AnyEvent signal handlers are, in addition, synchronous to the event loop,
		425	i.e. they will not interrupt your running perl program but will only be
		426	called as part of the normal event handling (just like timer, I/O etc.
		427	callbacks, too).
		428
		429	=head3 Signal Races, Delays and Workarounds
		430
		431	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
		432	callbacks to signals in a generic way, which is a pity, as you cannot
		433	do race-free signal handling in perl, requiring C libraries for
		434	this. AnyEvent will try to do its best, which means in some cases,
		435	signals will be delayed. The maximum time a signal might be delayed is
		436	specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This
		437	variable can be changed only before the first signal watcher is created,
		438	and should be left alone otherwise. This variable determines how often
		439	AnyEvent polls for signals (in case a wake-up was missed). Higher values
		440	will cause fewer spurious wake-ups, which is better for power and CPU
		441	saving.
		442
		443	All these problems can be avoided by installing the optional
		444	L<Async::Interrupt> module, which works with most event loops. It will not
		445	work with inherently broken event loops such as L<Event> or L<Event::Lib>
		446	(and not with L<POE> currently, as POE does its own workaround with
		447	one-second latency). For those, you just have to suffer the delays.
		448
375	=head2 CHILD PROCESS WATCHERS	449	=head2 CHILD PROCESS WATCHERS
376		450
		451	$w = AnyEvent->child (pid => <process id>, cb => <callback>);
		452
377	You can also watch on a child process exit and catch its exit status.	453	You can also watch for a child process exit and catch its exit status.
378		454
379	The child process is specified by the C<pid> argument (if set to C<0>, it	455	The child process is specified by the C<pid> argument (on some backends,
380	watches for any child process exit). The watcher will triggered only when	456	using C<0> watches for any child process exit, on others this will
381	the child process has finished and an exit status is available, not on	457	croak). The watcher will be triggered only when the child process has
382	any trace events (stopped/continued).	458	finished and an exit status is available, not on any trace events
		459	(stopped/continued).
383		460
384	The callback will be called with the pid and exit status (as returned by	461	The callback will be called with the pid and exit status (as returned by
385	waitpid), so unlike other watcher types, you I<can> rely on child watcher	462	waitpid), so unlike other watcher types, you I<can> rely on child watcher
386	callback arguments.	463	callback arguments.
387		464
…		…
403		480
404	This means you cannot create a child watcher as the very first	481	This means you cannot create a child watcher as the very first
405	thing in an AnyEvent program, you I<have> to create at least one	482	thing in an AnyEvent program, you I<have> to create at least one
406	watcher before you C<fork> the child (alternatively, you can call	483	watcher before you C<fork> the child (alternatively, you can call
407	C<AnyEvent::detect>).	484	C<AnyEvent::detect>).
		485
		486	As most event loops do not support waiting for child events, they will be
		487	emulated by AnyEvent in most cases, in which case the latency and race
		488	problems mentioned in the description of signal watchers apply.
408		489
409	Example: fork a process and wait for it	490	Example: fork a process and wait for it
410		491
411	my $done = AnyEvent->condvar;	492	my $done = AnyEvent->condvar;
412		493
…		…
424	# do something else, then wait for process exit	505	# do something else, then wait for process exit
425	$done->recv;	506	$done->recv;
426		507
427	=head2 IDLE WATCHERS	508	=head2 IDLE WATCHERS
428		509
429	Sometimes there is a need to do something, but it is not so important	510	$w = AnyEvent->idle (cb => <callback>);
430	to do it instantly, but only when there is nothing better to do. This
431	"nothing better to do" is usually defined to be "no other events need
432	attention by the event loop".
433		511
434	Idle watchers ideally get invoked when the event loop has nothing	512	This will repeatedly invoke the callback after the process becomes idle,
435	better to do, just before it would block the process to wait for new	513	until either the watcher is destroyed or new events have been detected.
436	events. Instead of blocking, the idle watcher is invoked.
437		514
438	Most event loops unfortunately do not really support idle watchers (only	515	Idle watchers are useful when there is a need to do something, but it
		516	is not so important (or wise) to do it instantly. The callback will be
		517	invoked only when there is "nothing better to do", which is usually
		518	defined as "all outstanding events have been handled and no new events
		519	have been detected". That means that idle watchers ideally get invoked
		520	when the event loop has just polled for new events but none have been
		521	detected. Instead of blocking to wait for more events, the idle watchers
		522	will be invoked.
		523
		524	Unfortunately, most event loops do not really support idle watchers (only
439	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent	525	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
440	will simply call the callback "from time to time".	526	will simply call the callback "from time to time".
441		527
442	Example: read lines from STDIN, but only process them when the	528	Example: read lines from STDIN, but only process them when the
443	program is otherwise idle:	529	program is otherwise idle:
…		…
459	});	545	});
460	});	546	});
461		547
462	=head2 CONDITION VARIABLES	548	=head2 CONDITION VARIABLES
463		549
		550	$cv = AnyEvent->condvar;
		551
		552	$cv->send (<list>);
		553	my @res = $cv->recv;
		554
464	If you are familiar with some event loops you will know that all of them	555	If you are familiar with some event loops you will know that all of them
465	require you to run some blocking "loop", "run" or similar function that	556	require you to run some blocking "loop", "run" or similar function that
466	will actively watch for new events and call your callbacks.	557	will actively watch for new events and call your callbacks.
467		558
468	AnyEvent is different, it expects somebody else to run the event loop and	559	AnyEvent is slightly different: it expects somebody else to run the event
469	will only block when necessary (usually when told by the user).	560	loop and will only block when necessary (usually when told by the user).
470		561
471	The instrument to do that is called a "condition variable", so called	562	The tool to do that is called a "condition variable", so called because
472	because they represent a condition that must become true.	563	they represent a condition that must become true.
		564
		565	Now is probably a good time to look at the examples further below.
473		566
474	Condition variables can be created by calling the C<< AnyEvent->condvar	567	Condition variables can be created by calling the C<< AnyEvent->condvar
475	>> method, usually without arguments. The only argument pair allowed is	568	>> method, usually without arguments. The only argument pair allowed is
476
477	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
478	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
479	the results).	571	the results).
480		572
481	After creation, the condition variable is "false" until it becomes "true"	573	After creation, the condition variable is "false" until it becomes "true"
482	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
483	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<<
484	->send >> method).	576	->send >> method).
485		577
486	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
487	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:
488	in time where multiple outstanding events have been processed. And yet	580
489	another way to call them is transactions - each condition variable can be	581	=over 4
490	used to represent a transaction, which finishes at some point and delivers	582
491	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
492		601
493	Condition variables are very useful to signal that something has finished,	602	Condition variables are very useful to signal that something has finished,
494	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,
495	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
496	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
…		…
509		618
510	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
511	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
512	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
513	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
514	it's C<new> method in your own C<new> method.	623	its C<new> method in your own C<new> method.
515		624
516	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
517	eventually calls C<< -> send >>, and the "consumer side", which waits	626	eventually calls C<< -> send >>, and the "consumer side", which waits
518	for the send to occur.	627	for the send to occur.
519		628
520	Example: wait for a timer.	629	Example: wait for a timer.
521		630
522	# wait till the result is ready	631	# condition: "wait till the timer is fired"
523	my $result_ready = AnyEvent->condvar;	632	my $timer_fired = AnyEvent->condvar;
524		633
525	# do something such as adding a timer	634	# create the timer - we could wait for, say
526	# or socket watcher the calls $result_ready->send	635	# a handle becomign ready, or even an
527	# when the "result" is ready.	636	# AnyEvent::HTTP request to finish, but
528	# in this case, we simply use a timer:	637	# in this case, we simply use a timer:
529	my $w = AnyEvent->timer (	638	my $w = AnyEvent->timer (
530	after => 1,	639	after => 1,
531	cb => sub { $result_ready->send },	640	cb => sub { $timer_fired->send },
532	);	641	);
533		642
534	# this "blocks" (while handling events) till the callback	643	# this "blocks" (while handling events) till the callback
535	# calls send	644	# calls ->send
536	$result_ready->recv;	645	$timer_fired->recv;
537		646
538	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
539	condition variables are also code references.	648	variables are also callable directly.
540		649
541	my $done = AnyEvent->condvar;	650	my $done = AnyEvent->condvar;
542	my $delay = AnyEvent->timer (after => 5, cb => $done);	651	my $delay = AnyEvent->timer (after => 5, cb => $done);
543	$done->recv;	652	$done->recv;
544		653
…		…
550		659
551	...	660	...
552		661
553	my @info = $couchdb->info->recv;	662	my @info = $couchdb->info->recv;
554		663
555	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
556	results are available:	665	results are available:
557		666
558	$couchdb->info->cb (sub {	667	$couchdb->info->cb (sub {
559	my @info = $_[0]->recv;	668	my @info = $_[0]->recv;
560	});	669	});
…		…
578	immediately from within send.	687	immediately from within send.
579		688
580	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
581	future C<< ->recv >> calls.	690	future C<< ->recv >> calls.
582		691
583	Condition variables are overloaded so one can call them directly	692	Condition variables are overloaded so one can call them directly (as if
584	(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
585	C<send>. Note, however, that many C-based event loops do not handle	694	C<send>.
586	overloading, so as tempting as it may be, passing a condition variable
587	instead of a callback does not work. Both the pure perl and EV loops
588	support overloading, however, as well as all functions that use perl to
589	invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
590	example).
591		695
592	=item $cv->croak ($error)	696	=item $cv->croak ($error)
593		697
594	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
595	C<Carp::croak> with the given error message/object/scalar.	699	C<Carp::croak> with the given error message/object/scalar.
596		700
597	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
598	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.
599		707
600	=item $cv->begin ([group callback])	708	=item $cv->begin ([group callback])
601		709
602	=item $cv->end	710	=item $cv->end
603
604	These two methods are EXPERIMENTAL and MIGHT CHANGE.
605		711
606	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
607	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
608	to use a condition variable for the whole process.	714	to use a condition variable for the whole process.
609		715
610	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
611	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
612	>>, 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
613	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
614	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.
615		722
616	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:
617		730
618	my $cv = AnyEvent->condvar;	731	my $cv = AnyEvent->condvar;
619		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
620	my %result;	757	my %result;
621	$cv->begin (sub { $cv->send (\%result) });	758	$cv->begin (sub { shift->send (\%result) });
622		759
623	for my $host (@list_of_hosts) {	760	for my $host (@list_of_hosts) {
624	$cv->begin;	761	$cv->begin;
625	ping_host_then_call_callback $host, sub {	762	ping_host_then_call_callback $host, sub {
626	$result{$host} = ...;	763	$result{$host} = ...;
…		…
641	loop, which serves two important purposes: first, it sets the callback	778	loop, which serves two important purposes: first, it sets the callback
642	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
643	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
644	doesn't execute once).	781	doesn't execute once).
645		782
646	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
647	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
648	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
649	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>.
650		788
651	=back	789	=back
652		790
653	=head3 METHODS FOR CONSUMERS	791	=head3 METHODS FOR CONSUMERS
654		792
…		…
658	=over 4	796	=over 4
659		797
660	=item $cv->recv	798	=item $cv->recv
661		799
662	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak	800	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
663	>> methods have been called on c<$cv>, while servicing other watchers	801	>> methods have been called on C<$cv>, while servicing other watchers
664	normally.	802	normally.
665		803
666	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
667	will return immediately.	805	will return immediately.
668		806
…		…
670	function will call C<croak>.	808	function will call C<croak>.
671		809
672	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,
673	in scalar context only the first one will be returned.	811	in scalar context only the first one will be returned.
674		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
675	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
676	(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
677	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
678	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
679	condition variables with some kind of request results and supporting	824	condition variables with some kind of request results and supporting
680	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,
681	while still supporting blocking waits if the caller so desires).	826	while still supporting blocking waits if the caller so desires).
682		827
683	Another reason I<never> to C<< ->recv >> in a module is that you cannot
684	sensibly have two C<< ->recv >>'s in parallel, as that would require
685	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
686	can supply.
687
688	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
689	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
690	versions and also integrates coroutines into AnyEvent, making blocking
691	C<< ->recv >> calls perfectly safe as long as they are done from another
692	coroutine (one that doesn't run the event loop).
693
694	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
695	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
696	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
697	waits otherwise.	831	waits otherwise.
698		832
699	=item $bool = $cv->ready	833	=item $bool = $cv->ready
…		…
705		839
706	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
707	replaces it before doing so.	841	replaces it before doing so.
708		842
709	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
710	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
711	variable itself. Calling C<recv> inside the callback or at any later time	845	condition variable itself. If the condition is already true, the
712	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.
713		848
714	=back	849	=back
715		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::FLTK 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
716	=head1 GLOBAL VARIABLES AND FUNCTIONS	914	=head1 GLOBAL VARIABLES AND FUNCTIONS
717		915
		916	These are not normally required to use AnyEvent, but can be useful to
		917	write AnyEvent extension modules.
		918
718	=over 4	919	=over 4
719		920
720	=item $AnyEvent::MODEL	921	=item $AnyEvent::MODEL
721		922
722	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
723	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
724	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
725	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
726	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
727		930	will be C<urxvt::anyevent>).
728	The known classes so far are:
729
730	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
731	AnyEvent::Impl::Event based on Event, second best choice.
732	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
733	AnyEvent::Impl::Glib based on Glib, third-best choice.
734	AnyEvent::Impl::Tk based on Tk, very bad choice.
735	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
736	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
737	AnyEvent::Impl::POE based on POE, not generic enough for full support.
738
739	# warning, support for IO::Async is only partial, as it is too broken
740	# and limited toe ven support the AnyEvent API. See AnyEvent::Impl::Async.
741	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed (see its docs).
742
743	There is no support for WxWidgets, as WxWidgets has no support for
744	watching file handles. However, you can use WxWidgets through the
745	POE Adaptor, as POE has a Wx backend that simply polls 20 times per
746	second, which was considered to be too horrible to even consider for
747	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
748	it's adaptor.
749
750	AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
751	autodetecting them.
752		931
753	=item AnyEvent::detect	932	=item AnyEvent::detect
754		933
755	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	934	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
756	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
757	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
758	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>.
759		945
760	=item $guard = AnyEvent::post_detect { BLOCK }	946	=item $guard = AnyEvent::post_detect { BLOCK }
761		947
762	Arranges for the code block to be executed as soon as the event model is	948	Arranges for the code block to be executed as soon as the event model is
763	autodetected (or immediately if this has already happened).	949	autodetected (or immediately if that has already happened).
		950
		951	The block will be executed I<after> the actual backend has been detected
		952	(C<$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.
764		961
765	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
766	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
767	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 ||= $guard;
768		982
769	=item @AnyEvent::post_detect	983	=item @AnyEvent::post_detect
770		984
771	If there are any code references in this array (you can C<push> to it	985	If there are any code references in this array (you can C<push> to it
772	before or after loading AnyEvent), then they will called directly after	986	before or after loading AnyEvent), then they will be called directly
773	the event loop has been chosen.	987	after the event loop has been chosen.
774		988
775	You should check C<$AnyEvent::MODEL> before adding to this array, though:	989	You should check C<$AnyEvent::MODEL> before adding to this array, though:
776	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
777	and the array will be ignored.	991	array will be ignored.
778		992
779	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<$level>.
		1057
		1058	If L<AnyEvent::Log> is not loaded then this function makes a simple test
		1059	to see whether the message will be logged. If the test succeeds it will
		1060	load AnyEvent::Log and call C<AnyEvent::Log::log> - consequently, look at
		1061	the L<AnyEvent::Log> documentation for details.
		1062
		1063	If the test fails it will simply return. Right now this happens when a
		1064	numerical loglevel is used and it is larger than the level specified via
		1065	C<$ENV{PERL_ANYEVENT_VERBOSE}>.
		1066
		1067	If you want to sprinkle loads of logging calls around your code, consider
		1068	creating a logger callback with the C<AnyEvent::Log::logger> function,
		1069	which can reduce typing, codesize and can reduce the logging overhead
		1070	enourmously.
780		1071
781	=back	1072	=back
782		1073
783	=head1 WHAT TO DO IN A MODULE	1074	=head1 WHAT TO DO IN A MODULE
784		1075
…		…
795	because it will stall the whole program, and the whole point of using	1086	because it will stall the whole program, and the whole point of using
796	events is to stay interactive.	1087	events is to stay interactive.
797		1088
798	It is fine, however, to call C<< ->recv >> when the user of your module	1089	It is fine, however, to call C<< ->recv >> when the user of your module
799	requests it (i.e. if you create a http request object ad have a method	1090	requests it (i.e. if you create a http request object ad have a method
800	called C<results> that returns the results, it should call C<< ->recv >>	1091	called C<results> that returns the results, it may call C<< ->recv >>
801	freely, as the user of your module knows what she is doing. always).	1092	freely, as the user of your module knows what she is doing. Always).
802		1093
803	=head1 WHAT TO DO IN THE MAIN PROGRAM	1094	=head1 WHAT TO DO IN THE MAIN PROGRAM
804		1095
805	There will always be a single main program - the only place that should	1096	There will always be a single main program - the only place that should
806	dictate which event model to use.	1097	dictate which event model to use.
807		1098
808	If it doesn't care, it can just "use AnyEvent" and use it itself, or not	1099	If the program is not event-based, it need not do anything special, even
809	do anything special (it does not need to be event-based) and let AnyEvent	1100	when it depends on a module that uses an AnyEvent. If the program itself
810	decide which implementation to chose if some module relies on it.	1101	uses AnyEvent, but does not care which event loop is used, all it needs
		1102	to do is C<use AnyEvent>. In either case, AnyEvent will choose the best
		1103	available loop implementation.
811		1104
812	If the main program relies on a specific event model - for example, in	1105	If the main program relies on a specific event model - for example, in
813	Gtk2 programs you have to rely on the Glib module - you should load the	1106	Gtk2 programs you have to rely on the Glib module - you should load the
814	event module before loading AnyEvent or any module that uses it: generally	1107	event module before loading AnyEvent or any module that uses it: generally
815	speaking, you should load it as early as possible. The reason is that	1108	speaking, you should load it as early as possible. The reason is that
816	modules might create watchers when they are loaded, and AnyEvent will	1109	modules might create watchers when they are loaded, and AnyEvent will
817	decide on the event model to use as soon as it creates watchers, and it	1110	decide on the event model to use as soon as it creates watchers, and it
818	might chose the wrong one unless you load the correct one yourself.	1111	might choose the wrong one unless you load the correct one yourself.
819		1112
820	You can chose to use a pure-perl implementation by loading the	1113	You can chose to use a pure-perl implementation by loading the
821	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour	1114	C<AnyEvent::Loop> module, which gives you similar behaviour
822	everywhere, but letting AnyEvent chose the model is generally better.	1115	everywhere, but letting AnyEvent chose the model is generally better.
823		1116
824	=head2 MAINLOOP EMULATION	1117	=head2 MAINLOOP EMULATION
825		1118
826	Sometimes (often for short test scripts, or even standalone programs who	1119	Sometimes (often for short test scripts, or even standalone programs who
…		…
839		1132
840		1133
841	=head1 OTHER MODULES	1134	=head1 OTHER MODULES
842		1135
843	The following is a non-exhaustive list of additional modules that use	1136	The following is a non-exhaustive list of additional modules that use
844	AnyEvent and can therefore be mixed easily with other AnyEvent modules	1137	AnyEvent as a client and can therefore be mixed easily with other
845	in the same program. Some of the modules come with AnyEvent, some are	1138	AnyEvent modules and other event loops in the same program. Some of the
846	available via CPAN.	1139	modules come as part of AnyEvent, the others are available via CPAN (see
		1140	L<http://search.cpan.org/search?m=module&q=anyevent%3A%3A*> for
		1141	a longer non-exhaustive list), and the list is heavily biased towards
		1142	modules of the AnyEvent author himself :)
847		1143
848	=over 4	1144	=over 4
849		1145
850	=item L<AnyEvent::Util>	1146	=item L<AnyEvent::Util>
851		1147
852	Contains various utility functions that replace often-used but blocking	1148	Contains various utility functions that replace often-used blocking
853	functions such as C<inet_aton> by event-/callback-based versions.	1149	functions such as C<inet_aton> with event/callback-based versions.
854		1150
855	=item L<AnyEvent::Socket>	1151	=item L<AnyEvent::Socket>
856		1152
857	Provides various utility functions for (internet protocol) sockets,	1153	Provides various utility functions for (internet protocol) sockets,
858	addresses and name resolution. Also functions to create non-blocking tcp	1154	addresses and name resolution. Also functions to create non-blocking tcp
…		…
860		1156
861	=item L<AnyEvent::Handle>	1157	=item L<AnyEvent::Handle>
862		1158
863	Provide read and write buffers, manages watchers for reads and writes,	1159	Provide read and write buffers, manages watchers for reads and writes,
864	supports raw and formatted I/O, I/O queued and fully transparent and	1160	supports raw and formatted I/O, I/O queued and fully transparent and
865	non-blocking SSL/TLS.	1161	non-blocking SSL/TLS (via L<AnyEvent::TLS>).
866		1162
867	=item L<AnyEvent::DNS>	1163	=item L<AnyEvent::DNS>
868		1164
869	Provides rich asynchronous DNS resolver capabilities.	1165	Provides rich asynchronous DNS resolver capabilities.
870		1166
		1167	=item L<AnyEvent::HTTP>, L<AnyEvent::IRC>, L<AnyEvent::XMPP>, L<AnyEvent::GPSD>, L<AnyEvent::IGS>, L<AnyEvent::FCP>
		1168
		1169	Implement event-based interfaces to the protocols of the same name (for
		1170	the curious, IGS is the International Go Server and FCP is the Freenet
		1171	Client Protocol).
		1172
871	=item L<AnyEvent::HTTP>	1173	=item L<AnyEvent::AIO>
872		1174
873	A simple-to-use HTTP library that is capable of making a lot of concurrent	1175	Truly asynchronous (as opposed to non-blocking) I/O, should be in the
874	HTTP requests.	1176	toolbox of every event programmer. AnyEvent::AIO transparently fuses
		1177	L<IO::AIO> and AnyEvent together, giving AnyEvent access to event-based
		1178	file I/O, and much more.
		1179
		1180	=item L<AnyEvent::Filesys::Notify>
		1181
		1182	AnyEvent is good for non-blocking stuff, but it can't detect file or
		1183	path changes (e.g. "watch this directory for new files", "watch this
		1184	file for changes"). The L<AnyEvent::Filesys::Notify> module promises to
		1185	do just that in a portbale fashion, supporting inotify on GNU/Linux and
		1186	some weird, without doubt broken, stuff on OS X to monitor files. It can
		1187	fall back to blocking scans at regular intervals transparently on other
		1188	platforms, so it's about as portable as it gets.
		1189
		1190	(I haven't used it myself, but I haven't heard anybody complaining about
		1191	it yet).
		1192
		1193	=item L<AnyEvent::DBI>
		1194
		1195	Executes L<DBI> requests asynchronously in a proxy process for you,
		1196	notifying you in an event-based way when the operation is finished.
875		1197
876	=item L<AnyEvent::HTTPD>	1198	=item L<AnyEvent::HTTPD>
877		1199
878	Provides a simple web application server framework.	1200	A simple embedded webserver.
879		1201
880	=item L<AnyEvent::FastPing>	1202	=item L<AnyEvent::FastPing>
881		1203
882	The fastest ping in the west.	1204	The fastest ping in the west.
883		1205
884	=item L<AnyEvent::DBI>
885
886	Executes L<DBI> requests asynchronously in a proxy process.
887
888	=item L<AnyEvent::AIO>
889
890	Truly asynchronous I/O, should be in the toolbox of every event
891	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
892	together.
893
894	=item L<AnyEvent::BDB>
895
896	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
897	L<BDB> and AnyEvent together.
898
899	=item L<AnyEvent::GPSD>
900
901	A non-blocking interface to gpsd, a daemon delivering GPS information.
902
903	=item L<AnyEvent::IGS>
904
905	A non-blocking interface to the Internet Go Server protocol (used by
906	L<App::IGS>).
907
908	=item L<AnyEvent::IRC>
909
910	AnyEvent based IRC client module family (replacing the older Net::IRC3).
911
912	=item L<Net::XMPP2>
913
914	AnyEvent based XMPP (Jabber protocol) module family.
915
916	=item L<Net::FCP>
917
918	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
919	of AnyEvent.
920
921	=item L<Event::ExecFlow>
922
923	High level API for event-based execution flow control.
924
925	=item L<Coro>	1206	=item L<Coro>
926		1207
927	Has special support for AnyEvent via L<Coro::AnyEvent>.	1208	Has special support for AnyEvent via L<Coro::AnyEvent>, which allows you
		1209	to simply invert the flow control - don't call us, we will call you:
928		1210
929	=item L<IO::Lambda>	1211	async {
		1212	Coro::AnyEvent::sleep 5; # creates a 5s timer and waits for it
		1213	print "5 seconds later!\n";
930		1214
931	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.	1215	Coro::AnyEvent::readable *STDIN; # uses an I/O watcher
		1216	my $line = <STDIN>; # works for ttys
		1217
		1218	AnyEvent::HTTP::http_get "url", Coro::rouse_cb;
		1219	my ($body, $hdr) = Coro::rouse_wait;
		1220	};
932		1221
933	=back	1222	=back
934		1223
935	=cut	1224	=cut
936		1225
937	package AnyEvent;	1226	package AnyEvent;
938		1227
939	no warnings;	1228	# basically a tuned-down version of common::sense
940	use strict qw(vars subs);	1229	sub common_sense {
		1230	# from common:.sense 3.4
		1231	${^WARNING_BITS} ^= ${^WARNING_BITS} ^ "\x3c\x3f\x33\x00\x0f\xf0\x0f\xc0\xf0\xfc\x33\x00";
		1232	# use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)
		1233	$^H |= 0x00000600;
		1234	}
941		1235
		1236	BEGIN { AnyEvent::common_sense }
		1237
942	use Carp;	1238	use Carp ();
943		1239
944	our $VERSION = 4.412;	1240	our $VERSION = '6.02';
945	our $MODEL;	1241	our $MODEL;
946
947	our $AUTOLOAD;
948	our @ISA;	1242	our @ISA;
949
950	our @REGISTRY;	1243	our @REGISTRY;
951		1244	our $VERBOSE;
952	our $WIN32;	1245	our $MAX_SIGNAL_LATENCY = 10;
		1246	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
953		1247
954	BEGIN {	1248	BEGIN {
955	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";	1249	require "AnyEvent/constants.pl";
		1250
956	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";	1251	eval "sub TAINT (){" . (${^TAINT}*1) . "}";
957		1252
958	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}	1253	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
959	if ${^TAINT};	1254	if ${^TAINT};
960	}
961		1255
962	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1256	$ENV{"PERL_ANYEVENT_$_"} = $ENV{"AE_$_"}
		1257	for grep s/^AE_// && !exists $ENV{"PERL_ANYEVENT_$_"}, keys %ENV;
963		1258
964	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred	1259	@ENV{grep /^PERL_ANYEVENT_/, keys %ENV} = ()
		1260	if ${^TAINT};
965		1261
966	{	1262	# $ENV{PERL_ANYEVENT_xxx} now valid
		1263
		1264	$VERBOSE = length $ENV{PERL_ANYEVENT_VERBOSE} ? $ENV{PERL_ANYEVENT_VERBOSE}*1 : 3;
		1265
967	my $idx;	1266	my $idx;
968	$PROTOCOL{$_} = ++$idx	1267	$PROTOCOL{$_} = ++$idx
969	for reverse split /\s*,\s*/,	1268	for reverse split /\s*,\s*/,
970	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1269	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
971	}	1270	}
972		1271
		1272	our @post_detect;
		1273
		1274	sub post_detect(&) {
		1275	my ($cb) = @_;
		1276
		1277	push @post_detect, $cb;
		1278
		1279	defined wantarray
		1280	? bless \$cb, "AnyEvent::Util::postdetect"
		1281	: ()
		1282	}
		1283
		1284	sub AnyEvent::Util::postdetect::DESTROY {
		1285	@post_detect = grep $_ != ${$_[0]}, @post_detect;
		1286	}
		1287
		1288	our $POSTPONE_W;
		1289	our @POSTPONE;
		1290
		1291	sub _postpone_exec {
		1292	undef $POSTPONE_W;
		1293
		1294	&{ shift @POSTPONE }
		1295	while @POSTPONE;
		1296	}
		1297
		1298	sub postpone(&) {
		1299	push @POSTPONE, shift;
		1300
		1301	$POSTPONE_W ||= AE::timer (0, 0, \&_postpone_exec);
		1302
		1303	()
		1304	}
		1305
		1306	sub log($$;@) {
		1307	# only load the big bloated module when we actually are about to log something
		1308	if ($_[0] <= $VERBOSE) { # also catches non-numeric levels(!)
		1309	require AnyEvent::Log;
		1310	# AnyEvent::Log overwrites this function
		1311	goto &log;
		1312	}
		1313
		1314	0 # not logged
		1315	}
		1316
		1317	if (length $ENV{PERL_ANYEVENT_LOG}) {
		1318	require AnyEvent::Log; # AnyEvent::Log does the thing for us
		1319	}
		1320
973	my @models = (	1321	our @models = (
974	[EV:: => AnyEvent::Impl::EV::],	1322	[EV:: => AnyEvent::Impl::EV:: , 1],
975	[Event:: => AnyEvent::Impl::Event::],	1323	[AnyEvent::Loop:: => AnyEvent::Impl::Perl:: , 1],
976	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
977	# everything below here will not be autoprobed	1324	# everything below here will not (normally) be autoprobed
978	# as the pureperl backend should work everywhere	1325	# as the pure perl backend should work everywhere
979	# and is usually faster	1326	# and is usually faster
		1327	[Event:: => AnyEvent::Impl::Event::, 1],
		1328	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
		1329	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
		1330	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
980	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1331	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
981	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
982	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
983	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1332	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
984	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1333	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
985	[Wx:: => AnyEvent::Impl::POE::],	1334	[Wx:: => AnyEvent::Impl::POE::],
986	[Prima:: => AnyEvent::Impl::POE::],	1335	[Prima:: => AnyEvent::Impl::POE::],
987	# IO::Async is just too broken - we would need workaorunds for its	1336	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # a bitch to autodetect
988	# byzantine signal and broken child handling, among others.	1337	[Cocoa::EventLoop:: => AnyEvent::Impl::Cocoa::],
989	# IO::Async is rather hard to detect, as it doesn't have any	1338	[FLTK:: => AnyEvent::Impl::FLTK::],
990	# obvious default class.
991	# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
992	# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
993	# [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
994	);	1339	);
995		1340
996	our %method = map +($_ => 1),	1341	our @isa_hook;
		1342
		1343	sub _isa_set {
		1344	my @pkg = ("AnyEvent", (map $_->[0], grep defined, @isa_hook), $MODEL);
		1345
		1346	@{"$pkg[$_-1]::ISA"} = $pkg[$_]
		1347	for 1 .. $#pkg;
		1348
		1349	grep $_ && $_->[1], @isa_hook
		1350	and AE::_reset ();
		1351	}
		1352
		1353	# used for hooking AnyEvent::Strict and AnyEvent::Debug::Wrap into the class hierarchy
		1354	sub _isa_hook($$;$) {
		1355	my ($i, $pkg, $reset_ae) = @_;
		1356
		1357	$isa_hook[$i] = $pkg ? [$pkg, $reset_ae] : undef;
		1358
		1359	_isa_set;
		1360	}
		1361
		1362	# all autoloaded methods reserve the complete glob, not just the method slot.
		1363	# due to bugs in perls method cache implementation.
997	qw(io timer time now now_update signal child idle condvar one_event DESTROY);	1364	our @methods = qw(io timer time now now_update signal child idle condvar);
998		1365
999	our @post_detect;
1000
1001	sub post_detect(&) {	1366	sub detect() {
1002	my ($cb) = @_;	1367	return $MODEL if $MODEL; # some programs keep references to detect
1003		1368
1004	if ($MODEL) {	1369	local $!; # for good measure
1005	$cb->();	1370	local $SIG{__DIE__}; # we use eval
1006		1371
1007	1	1372	# free some memory
		1373	*detect = sub () { $MODEL };
		1374	# undef &func doesn't correctly update the method cache. grmbl.
		1375	# so we delete the whole glob. grmbl.
		1376	# otoh, perl doesn't let me undef an active usb, but it lets me free
		1377	# a glob with an active sub. hrm. i hope it works, but perl is
		1378	# usually buggy in this department. sigh.
		1379	delete @{"AnyEvent::"}{@methods};
		1380	undef @methods;
		1381
		1382	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z0-9:]+)$/) {
		1383	my $model = $1;
		1384	$model = "AnyEvent::Impl::$model" unless $model =~ s/::$//;
		1385	if (eval "require $model") {
		1386	AnyEvent::log 7 => "loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.";
		1387	$MODEL = $model;
1008	} else {	1388	} else {
1009	push @post_detect, $cb;	1389	AnyEvent::log 5 => "unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@";
1010		1390	}
1011	defined wantarray
1012	? bless \$cb, "AnyEvent::Util::postdetect"
1013	: ()
1014	}	1391	}
1015	}
1016		1392
1017	sub AnyEvent::Util::postdetect::DESTROY {	1393	# check for already loaded models
1018	@post_detect = grep $_ != ${$_[0]}, @post_detect;
1019	}
1020
1021	sub detect() {
1022	unless ($MODEL) {	1394	unless ($MODEL) {
1023	no strict 'refs';	1395	for (@REGISTRY, @models) {
1024	local $SIG{__DIE__};	1396	my ($package, $model) = @$_;
1025		1397	if (${"$package\::VERSION"} > 0) {
1026	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
1027	my $model = "AnyEvent::Impl::$1";
1028	if (eval "require $model") {	1398	if (eval "require $model") {
		1399	AnyEvent::log 7 => "autodetected model '$model', using it.";
1029	$MODEL = $model;	1400	$MODEL = $model;
1030	warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1;	1401	last;
1031	} else {	1402	}
1032	warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose;
1033	}	1403	}
1034	}	1404	}
1035		1405
1036	# check for already loaded models
1037	unless ($MODEL) {	1406	unless ($MODEL) {
		1407	# try to autoload a model
1038	for (@REGISTRY, @models) {	1408	for (@REGISTRY, @models) {
1039	my ($package, $model) = @$_;	1409	my ($package, $model, $autoload) = @$_;
		1410	if (
		1411	$autoload
		1412	and eval "require $package"
1040	if (${"$package\::VERSION"} > 0) {	1413	and ${"$package\::VERSION"} > 0
1041	if (eval "require $model") {	1414	and eval "require $model"
		1415	) {
		1416	AnyEvent::log 7 => "autoloaded model '$model', using it.";
1042	$MODEL = $model;	1417	$MODEL = $model;
1043	warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1;
1044	last;	1418	last;
1045	}
1046	}	1419	}
1047	}	1420	}
1048		1421
1049	unless ($MODEL) {
1050	# try to load a model
1051
1052	for (@REGISTRY, @models) {
1053	my ($package, $model) = @$_;
1054	if (eval "require $package"
1055	and ${"$package\::VERSION"} > 0
1056	and eval "require $model") {
1057	$MODEL = $model;
1058	warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1;
1059	last;
1060	}
1061	}
1062
1063	$MODEL	1422	$MODEL
1064	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";	1423	or die "AnyEvent: backend autodetection failed - did you properly install AnyEvent?";
1065	}
1066	}	1424	}
1067
1068	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1069
1070	unshift @ISA, $MODEL;
1071
1072	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
1073
1074	(shift @post_detect)->() while @post_detect;
1075	}	1425	}
1076		1426
		1427	# free memory only needed for probing
		1428	undef @models;
		1429	undef @REGISTRY;
		1430
		1431	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1432
		1433	# now nuke some methods that are overridden by the backend.
		1434	# SUPER usage is not allowed in these.
		1435	for (qw(time signal child idle)) {
		1436	undef &{"AnyEvent::Base::$_"}
		1437	if defined &{"$MODEL\::$_"};
		1438	}
		1439
		1440	_isa_set;
		1441
		1442	# we're officially open!
		1443
		1444	if ($ENV{PERL_ANYEVENT_STRICT}) {
		1445	require AnyEvent::Strict;
		1446	}
		1447
		1448	if ($ENV{PERL_ANYEVENT_DEBUG_WRAP}) {
		1449	require AnyEvent::Debug;
		1450	AnyEvent::Debug::wrap ($ENV{PERL_ANYEVENT_DEBUG_WRAP});
		1451	}
		1452
		1453	if (length $ENV{PERL_ANYEVENT_DEBUG_SHELL}) {
		1454	require AnyEvent::Socket;
		1455	require AnyEvent::Debug;
		1456
		1457	my $shell = $ENV{PERL_ANYEVENT_DEBUG_SHELL};
		1458	$shell =~ s/\$\$/$$/g;
		1459
		1460	my ($host, $service) = AnyEvent::Socket::parse_hostport ($shell);
		1461	$AnyEvent::Debug::SHELL = AnyEvent::Debug::shell ($host, $service);
		1462	}
		1463
		1464	# now the anyevent environment is set up as the user told us to, so
		1465	# call the actual user code - post detects
		1466
		1467	(shift @post_detect)->() while @post_detect;
		1468	undef @post_detect;
		1469
		1470	*post_detect = sub(&) {
		1471	shift->();
		1472
		1473	undef
		1474	};
		1475
1077	$MODEL	1476	$MODEL
1078	}	1477	}
1079		1478
1080	sub AUTOLOAD {	1479	for my $name (@methods) {
1081	(my $func = $AUTOLOAD) =~ s/.*://;	1480	*$name = sub {
1082		1481	detect;
1083	$method{$func}	1482	# we use goto because
1084	or croak "$func: not a valid method for AnyEvent objects";	1483	# a) it makes the thunk more transparent
1085		1484	# b) it allows us to delete the thunk later
1086	detect unless $MODEL;	1485	goto &{ UNIVERSAL::can AnyEvent => "SUPER::$name" }
1087		1486	};
1088	my $class = shift;
1089	$class->$func (@_);
1090	}	1487	}
1091		1488
1092	# utility function to dup a filehandle. this is used by many backends	1489	# utility function to dup a filehandle. this is used by many backends
1093	# to support binding more than one watcher per filehandle (they usually	1490	# to support binding more than one watcher per filehandle (they usually
1094	# allow only one watcher per fd, so we dup it to get a different one).	1491	# allow only one watcher per fd, so we dup it to get a different one).
1095	sub _dupfh($$;$$) {	1492	sub _dupfh($$;$$) {
1096	my ($poll, $fh, $r, $w) = @_;	1493	my ($poll, $fh, $r, $w) = @_;
1097		1494
1098	# cygwin requires the fh mode to be matching, unix doesn't	1495	# cygwin requires the fh mode to be matching, unix doesn't
1099	my ($rw, $mode) = $poll eq "r" ? ($r, "<")	1496	my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1100	: $poll eq "w" ? ($w, ">")
1101	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1102		1497
1103	open my $fh2, "$mode&" . fileno $fh	1498	open my $fh2, $mode, $fh
1104	or die "cannot dup() filehandle: $!,";	1499	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1105		1500
1106	# we assume CLOEXEC is already set by perl in all important cases	1501	# we assume CLOEXEC is already set by perl in all important cases
1107		1502
1108	($fh2, $rw)	1503	($fh2, $rw)
1109	}	1504	}
1110		1505
		1506	=head1 SIMPLIFIED AE API
		1507
		1508	Starting with version 5.0, AnyEvent officially supports a second, much
		1509	simpler, API that is designed to reduce the calling, typing and memory
		1510	overhead by using function call syntax and a fixed number of parameters.
		1511
		1512	See the L<AE> manpage for details.
		1513
		1514	=cut
		1515
		1516	package AE;
		1517
		1518	our $VERSION = $AnyEvent::VERSION;
		1519
		1520	sub _reset() {
		1521	eval q{
		1522	# fall back to the main API by default - backends and AnyEvent::Base
		1523	# implementations can overwrite these.
		1524
		1525	sub io($$$) {
		1526	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
		1527	}
		1528
		1529	sub timer($$$) {
		1530	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
		1531	}
		1532
		1533	sub signal($$) {
		1534	AnyEvent->signal (signal => $_[0], cb => $_[1])
		1535	}
		1536
		1537	sub child($$) {
		1538	AnyEvent->child (pid => $_[0], cb => $_[1])
		1539	}
		1540
		1541	sub idle($) {
		1542	AnyEvent->idle (cb => $_[0]);
		1543	}
		1544
		1545	sub cv(;&) {
		1546	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
		1547	}
		1548
		1549	sub now() {
		1550	AnyEvent->now
		1551	}
		1552
		1553	sub now_update() {
		1554	AnyEvent->now_update
		1555	}
		1556
		1557	sub time() {
		1558	AnyEvent->time
		1559	}
		1560
		1561	*postpone = \&AnyEvent::postpone;
		1562	*log = \&AnyEvent::log;
		1563	};
		1564	die if $@;
		1565	}
		1566
		1567	BEGIN { _reset }
		1568
1111	package AnyEvent::Base;	1569	package AnyEvent::Base;
1112		1570
1113	# default implementations for many methods	1571	# default implementations for many methods
1114		1572
1115	BEGIN {	1573	sub time {
		1574	eval q{ # poor man's autoloading {}
		1575	# probe for availability of Time::HiRes
1116	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {	1576	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1577	*time = sub { Time::HiRes::time () };
1117	*_time = \&Time::HiRes::time;	1578	*AE::time = \& Time::HiRes::time ;
		1579	*now = \&time;
		1580	AnyEvent::log 8 => "AnyEvent: using Time::HiRes for sub-second timing accuracy.";
1118	# if (eval "use POSIX (); (POSIX::times())...	1581	# if (eval "use POSIX (); (POSIX::times())...
1119	} else {	1582	} else {
1120	*_time = sub { time }; # epic fail	1583	*time = sub { CORE::time };
		1584	*AE::time = sub (){ CORE::time };
		1585	*now = \&time;
		1586	AnyEvent::log 3 => "using built-in time(), WARNING, no sub-second resolution!";
		1587	}
		1588	};
		1589	die if $@;
		1590
		1591	&time
		1592	}
		1593
		1594	*now = \&time;
		1595	sub now_update { }
		1596
		1597	sub _poll {
		1598	Carp::croak "$AnyEvent::MODEL does not support blocking waits. Caught";
		1599	}
		1600
		1601	# default implementation for ->condvar
		1602	# in fact, the default should not be overwritten
		1603
		1604	sub condvar {
		1605	eval q{ # poor man's autoloading {}
		1606	*condvar = sub {
		1607	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
		1608	};
		1609
		1610	*AE::cv = sub (;&) {
		1611	bless { @_ ? (_ae_cb => shift) : () }, "AnyEvent::CondVar"
		1612	};
		1613	};
		1614	die if $@;
		1615
		1616	&condvar
		1617	}
		1618
		1619	# default implementation for ->signal
		1620
		1621	our $HAVE_ASYNC_INTERRUPT;
		1622
		1623	sub _have_async_interrupt() {
		1624	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
		1625	&& eval "use Async::Interrupt 1.02 (); 1")
		1626	unless defined $HAVE_ASYNC_INTERRUPT;
		1627
		1628	$HAVE_ASYNC_INTERRUPT
		1629	}
		1630
		1631	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1632	our (%SIG_ASY, %SIG_ASY_W);
		1633	our ($SIG_COUNT, $SIG_TW);
		1634
		1635	# install a dummy wakeup watcher to reduce signal catching latency
		1636	# used by Impls
		1637	sub _sig_add() {
		1638	unless ($SIG_COUNT++) {
		1639	# try to align timer on a full-second boundary, if possible
		1640	my $NOW = AE::now;
		1641
		1642	$SIG_TW = AE::timer
		1643	$MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
		1644	$MAX_SIGNAL_LATENCY,
		1645	sub { } # just for the PERL_ASYNC_CHECK
		1646	;
1121	}	1647	}
1122	}	1648	}
1123		1649
1124	sub time { _time }	1650	sub _sig_del {
1125	sub now { _time }	1651	undef $SIG_TW
1126	sub now_update { }	1652	unless --$SIG_COUNT;
1127
1128	# default implementation for ->condvar
1129
1130	sub condvar {
1131	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1132	}	1653	}
1133		1654
1134	# default implementation for ->signal	1655	our $_sig_name_init; $_sig_name_init = sub {
		1656	eval q{ # poor man's autoloading {}
		1657	undef $_sig_name_init;
1135		1658
1136	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1659	if (_have_async_interrupt) {
		1660	*sig2num = \&Async::Interrupt::sig2num;
		1661	*sig2name = \&Async::Interrupt::sig2name;
		1662	} else {
		1663	require Config;
1137		1664
1138	sub _signal_exec {	1665	my %signame2num;
1139	sysread $SIGPIPE_R, my $dummy, 4;	1666	@signame2num{ split ' ', $Config::Config{sig_name} }
		1667	= split ' ', $Config::Config{sig_num};
1140		1668
1141	while (%SIG_EV) {	1669	my @signum2name;
1142	for (keys %SIG_EV) {	1670	@signum2name[values %signame2num] = keys %signame2num;
1143	delete $SIG_EV{$_};	1671
1144	$_->() for values %{ $SIG_CB{$_} || {} };	1672	*sig2num = sub($) {
		1673	$_[0] > 0 ? shift : $signame2num{+shift}
		1674	};
		1675	*sig2name = sub ($) {
		1676	$_[0] > 0 ? $signum2name[+shift] : shift
		1677	};
1145	}	1678	}
1146	}	1679	};
1147	}	1680	die if $@;
		1681	};
		1682
		1683	sub sig2num ($) { &$_sig_name_init; &sig2num }
		1684	sub sig2name($) { &$_sig_name_init; &sig2name }
1148		1685
1149	sub signal {	1686	sub signal {
1150	my (undef, %arg) = @_;	1687	eval q{ # poor man's autoloading {}
		1688	# probe for availability of Async::Interrupt
		1689	if (_have_async_interrupt) {
		1690	AnyEvent::log 8 => "using Async::Interrupt for race-free signal handling.";
1151		1691
1152	unless ($SIGPIPE_R) {	1692	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1153	require Fcntl;	1693	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1154		1694
1155	if (AnyEvent::WIN32) {
1156	require AnyEvent::Util;
1157
1158	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1159	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1160	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1161	} else {	1695	} else {
		1696	AnyEvent::log 8 => "using emulated perl signal handling with latency timer.";
		1697
		1698	if (AnyEvent::WIN32) {
		1699	require AnyEvent::Util;
		1700
		1701	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1702	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
		1703	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
		1704	} else {
1162	pipe $SIGPIPE_R, $SIGPIPE_W;	1705	pipe $SIGPIPE_R, $SIGPIPE_W;
1163	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;	1706	fcntl $SIGPIPE_R, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_R;
1164	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case	1707	fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case
1165		1708
1166	# not strictly required, as $^F is normally 2, but let's make sure...	1709	# not strictly required, as $^F is normally 2, but let's make sure...
1167	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1710	fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
1168	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1711	fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
		1712	}
		1713
		1714	$SIGPIPE_R
		1715	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1716
		1717	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
1169	}	1718	}
1170		1719
1171	$SIGPIPE_R	1720	*signal = $HAVE_ASYNC_INTERRUPT
1172	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";	1721	? sub {
		1722	my (undef, %arg) = @_;
1173		1723
1174	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);	1724	# async::interrupt
1175	}
1176
1177	my $signal = uc $arg{signal}	1725	my $signal = sig2num $arg{signal};
1178	or Carp::croak "required option 'signal' is missing";
1179
1180	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1726	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1727
		1728	$SIG_ASY{$signal} ||= new Async::Interrupt
		1729	cb => sub { undef $SIG_EV{$signal} },
		1730	signal => $signal,
		1731	pipe => [$SIGPIPE_R->filenos],
		1732	pipe_autodrain => 0,
		1733	;
		1734
		1735	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1736	}
		1737	: sub {
		1738	my (undef, %arg) = @_;
		1739
		1740	# pure perl
		1741	my $signal = sig2name $arg{signal};
		1742	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1743
1181	$SIG{$signal} ||= sub {	1744	$SIG{$signal} ||= sub {
1182	local $!;	1745	local $!;
1183	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;	1746	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1184	undef $SIG_EV{$signal};	1747	undef $SIG_EV{$signal};
		1748	};
		1749
		1750	# can't do signal processing without introducing races in pure perl,
		1751	# so limit the signal latency.
		1752	_sig_add;
		1753
		1754	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1755	}
		1756	;
		1757
		1758	*AnyEvent::Base::signal::DESTROY = sub {
		1759	my ($signal, $cb) = @{$_[0]};
		1760
		1761	_sig_del;
		1762
		1763	delete $SIG_CB{$signal}{$cb};
		1764
		1765	$HAVE_ASYNC_INTERRUPT
		1766	? delete $SIG_ASY{$signal}
		1767	: # delete doesn't work with older perls - they then
		1768	# print weird messages, or just unconditionally exit
		1769	# instead of getting the default action.
		1770	undef $SIG{$signal}
		1771	unless keys %{ $SIG_CB{$signal} };
		1772	};
		1773
		1774	*_signal_exec = sub {
		1775	$HAVE_ASYNC_INTERRUPT
		1776	? $SIGPIPE_R->drain
		1777	: sysread $SIGPIPE_R, (my $dummy), 9;
		1778
		1779	while (%SIG_EV) {
		1780	for (keys %SIG_EV) {
		1781	delete $SIG_EV{$_};
		1782	&$_ for values %{ $SIG_CB{$_} || {} };
		1783	}
		1784	}
		1785	};
1185	};	1786	};
		1787	die if $@;
1186		1788
1187	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"	1789	&signal
1188	}
1189
1190	sub AnyEvent::Base::signal::DESTROY {
1191	my ($signal, $cb) = @{$_[0]};
1192
1193	delete $SIG_CB{$signal}{$cb};
1194
1195	# delete doesn't work with older perls - they then
1196	# print weird messages, or just unconditionally exit
1197	# instead of getting the default action.
1198	undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
1199	}	1790	}
1200		1791
1201	# default implementation for ->child	1792	# default implementation for ->child
1202		1793
1203	our %PID_CB;	1794	our %PID_CB;
1204	our $CHLD_W;	1795	our $CHLD_W;
1205	our $CHLD_DELAY_W;	1796	our $CHLD_DELAY_W;
1206	our $WNOHANG;
1207		1797
1208	sub _sigchld {	1798	# used by many Impl's
1209	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1799	sub _emit_childstatus($$) {
		1800	my (undef, $rpid, $rstatus) = @_;
		1801
		1802	$_->($rpid, $rstatus)
1210	$_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),	1803	for values %{ $PID_CB{$rpid} || {} },
1211	(values %{ $PID_CB{0} || {} });	1804	values %{ $PID_CB{0} || {} };
1212	}
1213	}	1805	}
1214		1806
1215	sub child {	1807	sub child {
		1808	eval q{ # poor man's autoloading {}
		1809	*_sigchld = sub {
		1810	my $pid;
		1811
		1812	AnyEvent->_emit_childstatus ($pid, $?)
		1813	while ($pid = waitpid -1, WNOHANG) > 0;
		1814	};
		1815
		1816	*child = sub {
1216	my (undef, %arg) = @_;	1817	my (undef, %arg) = @_;
1217		1818
1218	defined (my $pid = $arg{pid} + 0)	1819	my $pid = $arg{pid};
1219	or Carp::croak "required option 'pid' is missing";	1820	my $cb = $arg{cb};
1220		1821
1221	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1822	$PID_CB{$pid}{$cb+0} = $cb;
1222		1823
1223	$WNOHANG ||= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1224
1225	unless ($CHLD_W) {	1824	unless ($CHLD_W) {
1226	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1825	$CHLD_W = AE::signal CHLD => \&_sigchld;
1227	# child could be a zombie already, so make at least one round	1826	# child could be a zombie already, so make at least one round
1228	&_sigchld;	1827	&_sigchld;
1229	}	1828	}
1230		1829
1231	bless [$pid, $arg{cb}], "AnyEvent::Base::child"	1830	bless [$pid, $cb+0], "AnyEvent::Base::child"
1232	}	1831	};
1233		1832
1234	sub AnyEvent::Base::child::DESTROY {	1833	*AnyEvent::Base::child::DESTROY = sub {
1235	my ($pid, $cb) = @{$_[0]};	1834	my ($pid, $icb) = @{$_[0]};
1236		1835
1237	delete $PID_CB{$pid}{$cb};	1836	delete $PID_CB{$pid}{$icb};
1238	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1837	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1239		1838
1240	undef $CHLD_W unless keys %PID_CB;	1839	undef $CHLD_W unless keys %PID_CB;
		1840	};
		1841	};
		1842	die if $@;
		1843
		1844	&child
1241	}	1845	}
1242		1846
1243	# idle emulation is done by simply using a timer, regardless	1847	# idle emulation is done by simply using a timer, regardless
1244	# of whether the process is idle or not, and not letting	1848	# of whether the process is idle or not, and not letting
1245	# the callback use more than 50% of the time.	1849	# the callback use more than 50% of the time.
1246	sub idle {	1850	sub idle {
		1851	eval q{ # poor man's autoloading {}
		1852	*idle = sub {
1247	my (undef, %arg) = @_;	1853	my (undef, %arg) = @_;
1248		1854
1249	my ($cb, $w, $rcb) = $arg{cb};	1855	my ($cb, $w, $rcb) = $arg{cb};
1250		1856
1251	$rcb = sub {	1857	$rcb = sub {
1252	if ($cb) {	1858	if ($cb) {
1253	$w = _time;	1859	$w = AE::time;
1254	&$cb;	1860	&$cb;
1255	$w = _time - $w;	1861	$w = AE::time - $w;
1256		1862
1257	# never use more then 50% of the time for the idle watcher,	1863	# never use more then 50% of the time for the idle watcher,
1258	# within some limits	1864	# within some limits
1259	$w = 0.0001 if $w < 0.0001;	1865	$w = 0.0001 if $w < 0.0001;
1260	$w = 5 if $w > 5;	1866	$w = 5 if $w > 5;
1261		1867
1262	$w = AnyEvent->timer (after => $w, cb => $rcb);	1868	$w = AE::timer $w, 0, $rcb;
1263	} else {	1869	} else {
1264	# clean up...	1870	# clean up...
1265	undef $w;	1871	undef $w;
1266	undef $rcb;	1872	undef $rcb;
		1873	}
		1874	};
		1875
		1876	$w = AE::timer 0.05, 0, $rcb;
		1877
		1878	bless \\$cb, "AnyEvent::Base::idle"
1267	}	1879	};
		1880
		1881	*AnyEvent::Base::idle::DESTROY = sub {
		1882	undef $${$_[0]};
		1883	};
1268	};	1884	};
		1885	die if $@;
1269		1886
1270	$w = AnyEvent->timer (after => 0.05, cb => $rcb);	1887	&idle
1271
1272	bless \\$cb, "AnyEvent::Base::idle"
1273	}
1274
1275	sub AnyEvent::Base::idle::DESTROY {
1276	undef $${$_[0]};
1277	}	1888	}
1278		1889
1279	package AnyEvent::CondVar;	1890	package AnyEvent::CondVar;
1280		1891
1281	our @ISA = AnyEvent::CondVar::Base::;	1892	our @ISA = AnyEvent::CondVar::Base::;
1282		1893
		1894	# only to be used for subclassing
		1895	sub new {
		1896	my $class = shift;
		1897	bless AnyEvent->condvar (@_), $class
		1898	}
		1899
1283	package AnyEvent::CondVar::Base;	1900	package AnyEvent::CondVar::Base;
1284		1901
1285	use overload	1902	#use overload
1286	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1903	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1287	fallback => 1;	1904	# fallback => 1;
		1905
		1906	# save 300+ kilobytes by dirtily hardcoding overloading
		1907	${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
		1908	*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
		1909	*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
		1910	${'AnyEvent::CondVar::Base::()'} = 1; # fallback
		1911
		1912	our $WAITING;
1288		1913
1289	sub _send {	1914	sub _send {
1290	# nop	1915	# nop
		1916	}
		1917
		1918	sub _wait {
		1919	AnyEvent->_poll until $_[0]{_ae_sent};
1291	}	1920	}
1292		1921
1293	sub send {	1922	sub send {
1294	my $cv = shift;	1923	my $cv = shift;
1295	$cv->{_ae_sent} = [@_];	1924	$cv->{_ae_sent} = [@_];
…		…
1304		1933
1305	sub ready {	1934	sub ready {
1306	$_[0]{_ae_sent}	1935	$_[0]{_ae_sent}
1307	}	1936	}
1308		1937
1309	sub _wait {
1310	AnyEvent->one_event while !$_[0]{_ae_sent};
1311	}
1312
1313	sub recv {	1938	sub recv {
		1939	unless ($_[0]{_ae_sent}) {
		1940	$WAITING
		1941	and Carp::croak "AnyEvent::CondVar: recursive blocking wait attempted";
		1942
		1943	local $WAITING = 1;
1314	$_[0]->_wait;	1944	$_[0]->_wait;
		1945	}
1315		1946
1316	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1947	$_[0]{_ae_croak}
1317	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1948	and Carp::croak $_[0]{_ae_croak};
		1949
		1950	wantarray
		1951	? @{ $_[0]{_ae_sent} }
		1952	: $_[0]{_ae_sent}[0]
1318	}	1953	}
1319		1954
1320	sub cb {	1955	sub cb {
1321	$_[0]{_ae_cb} = $_[1] if @_ > 1;	1956	my $cv = shift;
		1957
		1958	@_
		1959	and $cv->{_ae_cb} = shift
		1960	and $cv->{_ae_sent}
		1961	and (delete $cv->{_ae_cb})->($cv);
		1962
1322	$_[0]{_ae_cb}	1963	$cv->{_ae_cb}
1323	}	1964	}
1324		1965
1325	sub begin {	1966	sub begin {
1326	++$_[0]{_ae_counter};	1967	++$_[0]{_ae_counter};
1327	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;	1968	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
…		…
1332	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };	1973	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };
1333	}	1974	}
1334		1975
1335	# undocumented/compatibility with pre-3.4	1976	# undocumented/compatibility with pre-3.4
1336	*broadcast = \&send;	1977	*broadcast = \&send;
1337	*wait = \&_wait;	1978	*wait = \&recv;
1338		1979
1339	=head1 ERROR AND EXCEPTION HANDLING	1980	=head1 ERROR AND EXCEPTION HANDLING
1340		1981
1341	In general, AnyEvent does not do any error handling - it relies on the	1982	In general, AnyEvent does not do any error handling - it relies on the
1342	caller to do that if required. The L<AnyEvent::Strict> module (see also	1983	caller to do that if required. The L<AnyEvent::Strict> module (see also
…		…
1354	$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and	1995	$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and
1355	so on.	1996	so on.
1356		1997
1357	=head1 ENVIRONMENT VARIABLES	1998	=head1 ENVIRONMENT VARIABLES
1358		1999
1359	The following environment variables are used by this module or its	2000	AnyEvent supports a number of environment variables that tune the
1360	submodules.	2001	runtime behaviour. They are usually evaluated when AnyEvent is
		2002	loaded, initialised, or a submodule that uses them is loaded. Many of
		2003	them also cause AnyEvent to load additional modules - for example,
		2004	C<PERL_ANYEVENT_DEBUG_WRAP> causes the L<AnyEvent::Debug> module to be
		2005	loaded.
1361		2006
1362	Note that AnyEvent will remove I<all> environment variables starting with	2007	All the environment variables documented here start with
1363	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is	2008	C<PERL_ANYEVENT_>, which is what AnyEvent considers its own
1364	enabled.	2009	namespace. Other modules are encouraged (but by no means required) to use
		2010	C<PERL_ANYEVENT_SUBMODULE> if they have registered the AnyEvent::Submodule
		2011	namespace on CPAN, for any submodule. For example, L<AnyEvent::HTTP> could
		2012	be expected to use C<PERL_ANYEVENT_HTTP_PROXY> (it should not access env
		2013	variables starting with C<AE_>, see below).
		2014
		2015	All variables can also be set via the C<AE_> prefix, that is, instead
		2016	of setting C<PERL_ANYEVENT_VERBOSE> you can also set C<AE_VERBOSE>. In
		2017	case there is a clash btween anyevent and another program that uses
		2018	C<AE_something> you can set the corresponding C<PERL_ANYEVENT_something>
		2019	variable to the empty string, as those variables take precedence.
		2020
		2021	When AnyEvent is first loaded, it copies all C<AE_xxx> env variables
		2022	to their C<PERL_ANYEVENT_xxx> counterpart unless that variable already
		2023	exists. If taint mode is on, then AnyEvent will remove I<all> environment
		2024	variables starting with C<PERL_ANYEVENT_> from C<%ENV> (or replace them
		2025	with C<undef> or the empty string, if the corresaponding C<AE_> variable
		2026	is set).
		2027
		2028	The exact algorithm is currently:
		2029
		2030	1. if taint mode enabled, delete all PERL_ANYEVENT_xyz variables from %ENV
		2031	2. copy over AE_xyz to PERL_ANYEVENT_xyz unless the latter alraedy exists
		2032	3. if taint mode enabled, set all PERL_ANYEVENT_xyz variables to undef.
		2033
		2034	This ensures that child processes will not see the C<AE_> variables.
		2035
		2036	The following environment variables are currently known to AnyEvent:
1365		2037
1366	=over 4	2038	=over 4
1367		2039
1368	=item C<PERL_ANYEVENT_VERBOSE>	2040	=item C<PERL_ANYEVENT_VERBOSE>
1369		2041
1370	By default, AnyEvent will be completely silent except in fatal	2042	By default, AnyEvent will only log messages with loglevel C<3>
1371	conditions. You can set this environment variable to make AnyEvent more	2043	(C<critical>) or higher (see L<AnyEvent::Log>). You can set this
		2044	environment variable to a numerical loglevel to make AnyEvent more (or
1372	talkative.	2045	less) talkative.
1373		2046
		2047	If you want to do more than just set the global logging level
		2048	you should have a look at C<PERL_ANYEVENT_LOG>, which allows much more
		2049	complex specifications.
		2050
		2051	When set to C<0> (C<off>), then no messages whatsoever will be logged with
		2052	the default logging settings.
		2053
1374	When set to C<1> or higher, causes AnyEvent to warn about unexpected	2054	When set to C<5> or higher (C<warn>), causes AnyEvent to warn about
1375	conditions, such as not being able to load the event model specified by	2055	unexpected conditions, such as not being able to load the event model
1376	C<PERL_ANYEVENT_MODEL>.	2056	specified by C<PERL_ANYEVENT_MODEL>, or a guard callback throwing an
		2057	exception - this is the minimum recommended level.
1377		2058
1378	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	2059	When set to C<7> or higher (info), cause AnyEvent to report which event model it
1379	model it chooses.	2060	chooses.
		2061
		2062	When set to C<8> or higher (debug), then AnyEvent will report extra information on
		2063	which optional modules it loads and how it implements certain features.
		2064
		2065	=item C<PERL_ANYEVENT_LOG>
		2066
		2067	Accepts rather complex logging specifications. For example, you could log
		2068	all C<debug> messages of some module to stderr, warnings and above to
		2069	stderr, and errors and above to syslog, with:
		2070
		2071	PERL_ANYEVENT_LOG=Some::Module=debug,+log:filter=warn,+%syslog:%syslog=error,syslog
		2072
		2073	For the rather extensive details, see L<AnyEvent::Log>.
		2074
		2075	This variable is evaluated when AnyEvent (or L<AnyEvent::Log>) is loaded,
		2076	so will take effect even before AnyEvent has initialised itself.
		2077
		2078	Note that specifying this environment variable causes the L<AnyEvent::Log>
		2079	module to be loaded, while C<PERL_ANYEVENT_VERBOSE> does not, so only
		2080	using the latter saves a few hundred kB of memory until the first message
		2081	is being logged.
1380		2082
1381	=item C<PERL_ANYEVENT_STRICT>	2083	=item C<PERL_ANYEVENT_STRICT>
1382		2084
1383	AnyEvent does not do much argument checking by default, as thorough	2085	AnyEvent does not do much argument checking by default, as thorough
1384	argument checking is very costly. Setting this variable to a true value	2086	argument checking is very costly. Setting this variable to a true value
…		…
1386	check the arguments passed to most method calls. If it finds any problems,	2088	check the arguments passed to most method calls. If it finds any problems,
1387	it will croak.	2089	it will croak.
1388		2090
1389	In other words, enables "strict" mode.	2091	In other words, enables "strict" mode.
1390		2092
1391	Unlike C<use strict>, it is definitely recommended to keep it off in	2093	Unlike C<use strict> (or its modern cousin, C<< use L<common::sense>
1392	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while	2094	>>, it is definitely recommended to keep it off in production. Keeping
1393	developing programs can be very useful, however.	2095	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
		2096	can be very useful, however.
		2097
		2098	=item C<PERL_ANYEVENT_DEBUG_SHELL>
		2099
		2100	If this env variable is set, then its contents will be interpreted by
		2101	C<AnyEvent::Socket::parse_hostport> (after replacing every occurance of
		2102	C<$$> by the process pid) and an C<AnyEvent::Debug::shell> is bound on
		2103	that port. The shell object is saved in C<$AnyEvent::Debug::SHELL>.
		2104
		2105	This happens when the first watcher is created.
		2106
		2107	For example, to bind a debug shell on a unix domain socket in
		2108	F<< /tmp/debug<pid>.sock >>, you could use this:
		2109
		2110	PERL_ANYEVENT_DEBUG_SHELL=/tmp/debug\$\$.sock perlprog
		2111
		2112	Note that creating sockets in F</tmp> is very unsafe on multiuser
		2113	systems.
		2114
		2115	=item C<PERL_ANYEVENT_DEBUG_WRAP>
		2116
		2117	Can be set to C<0>, C<1> or C<2> and enables wrapping of all watchers for
		2118	debugging purposes. See C<AnyEvent::Debug::wrap> for details.
1394		2119
1395	=item C<PERL_ANYEVENT_MODEL>	2120	=item C<PERL_ANYEVENT_MODEL>
1396		2121
1397	This can be used to specify the event model to be used by AnyEvent, before	2122	This can be used to specify the event model to be used by AnyEvent, before
1398	auto detection and -probing kicks in. It must be a string consisting	2123	auto detection and -probing kicks in.
1399	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended	2124
		2125	It normally is a string consisting entirely of ASCII letters (e.g. C<EV>
		2126	or C<IOAsync>). The string C<AnyEvent::Impl::> gets prepended and the
1400	and the resulting module name is loaded and if the load was successful,	2127	resulting module name is loaded and - if the load was successful - used as
1401	used as event model. If it fails to load AnyEvent will proceed with	2128	event model backend. If it fails to load then AnyEvent will proceed with
1402	auto detection and -probing.	2129	auto detection and -probing.
1403		2130
1404	This functionality might change in future versions.	2131	If the string ends with C<::> instead (e.g. C<AnyEvent::Impl::EV::>) then
		2132	nothing gets prepended and the module name is used as-is (hint: C<::> at
		2133	the end of a string designates a module name and quotes it appropriately).
1405		2134
1406	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you	2135	For example, to force the pure perl model (L<AnyEvent::Loop::Perl>) you
1407	could start your program like this:	2136	could start your program like this:
1408		2137
1409	PERL_ANYEVENT_MODEL=Perl perl ...	2138	PERL_ANYEVENT_MODEL=Perl perl ...
1410		2139
1411	=item C<PERL_ANYEVENT_PROTOCOLS>	2140	=item C<PERL_ANYEVENT_PROTOCOLS>
…		…
1427	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>	2156	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1428	- only support IPv4, never try to resolve or contact IPv6	2157	- only support IPv4, never try to resolve or contact IPv6
1429	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or	2158	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1430	IPv6, but prefer IPv6 over IPv4.	2159	IPv6, but prefer IPv6 over IPv4.
1431		2160
		2161	=item C<PERL_ANYEVENT_HOSTS>
		2162
		2163	This variable, if specified, overrides the F</etc/hosts> file used by
		2164	L<AnyEvent::Socket>C<::resolve_sockaddr>, i.e. hosts aliases will be read
		2165	from that file instead.
		2166
1432	=item C<PERL_ANYEVENT_EDNS0>	2167	=item C<PERL_ANYEVENT_EDNS0>
1433		2168
1434	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension	2169	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension for
1435	for DNS. This extension is generally useful to reduce DNS traffic, but	2170	DNS. This extension is generally useful to reduce DNS traffic, especially
1436	some (broken) firewalls drop such DNS packets, which is why it is off by	2171	when DNSSEC is involved, but some (broken) firewalls drop such DNS
1437	default.	2172	packets, which is why it is off by default.
1438		2173
1439	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce	2174	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1440	EDNS0 in its DNS requests.	2175	EDNS0 in its DNS requests.
1441		2176
1442	=item C<PERL_ANYEVENT_MAX_FORKS>	2177	=item C<PERL_ANYEVENT_MAX_FORKS>
1443		2178
1444	The maximum number of child processes that C<AnyEvent::Util::fork_call>	2179	The maximum number of child processes that C<AnyEvent::Util::fork_call>
1445	will create in parallel.	2180	will create in parallel.
		2181
		2182	=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
		2183
		2184	The default value for the C<max_outstanding> parameter for the default DNS
		2185	resolver - this is the maximum number of parallel DNS requests that are
		2186	sent to the DNS server.
		2187
		2188	=item C<PERL_ANYEVENT_RESOLV_CONF>
		2189
		2190	The absolute path to a F<resolv.conf>-style file to use instead of
		2191	F</etc/resolv.conf> (or the OS-specific configuration) in the default
		2192	resolver, or the empty string to select the default configuration.
		2193
		2194	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
		2195
		2196	When neither C<ca_file> nor C<ca_path> was specified during
		2197	L<AnyEvent::TLS> context creation, and either of these environment
		2198	variables are nonempty, they will be used to specify CA certificate
		2199	locations instead of a system-dependent default.
		2200
		2201	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
		2202
		2203	When these are set to C<1>, then the respective modules are not
		2204	loaded. Mostly good for testing AnyEvent itself.
1446		2205
1447	=back	2206	=back
1448		2207
1449	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	2208	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1450		2209
…		…
1508	warn "read: $input\n"; # output what has been read	2267	warn "read: $input\n"; # output what has been read
1509	$cv->send if $input =~ /^q/i; # quit program if /^q/i	2268	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1510	},	2269	},
1511	);	2270	);
1512		2271
1513	my $time_watcher; # can only be used once
1514
1515	sub new_timer {
1516	$timer = AnyEvent->timer (after => 1, cb => sub {	2272	my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1517	warn "timeout\n"; # print 'timeout' about every second	2273	warn "timeout\n"; # print 'timeout' at most every second
1518	&new_timer; # and restart the time
1519	});	2274	});
1520	}
1521
1522	new_timer; # create first timer
1523		2275
1524	$cv->recv; # wait until user enters /^q/i	2276	$cv->recv; # wait until user enters /^q/i
1525		2277
1526	=head1 REAL-WORLD EXAMPLE	2278	=head1 REAL-WORLD EXAMPLE
1527		2279
…		…
1600		2352
1601	The actual code goes further and collects all errors (C<die>s, exceptions)	2353	The actual code goes further and collects all errors (C<die>s, exceptions)
1602	that occurred during request processing. The C<result> method detects	2354	that occurred during request processing. The C<result> method detects
1603	whether an exception as thrown (it is stored inside the $txn object)	2355	whether an exception as thrown (it is stored inside the $txn object)
1604	and just throws the exception, which means connection errors and other	2356	and just throws the exception, which means connection errors and other
1605	problems get reported tot he code that tries to use the result, not in a	2357	problems get reported to the code that tries to use the result, not in a
1606	random callback.	2358	random callback.
1607		2359
1608	All of this enables the following usage styles:	2360	All of this enables the following usage styles:
1609		2361
1610	1. Blocking:	2362	1. Blocking:
…		…
1658	through AnyEvent. The benchmark creates a lot of timers (with a zero	2410	through AnyEvent. The benchmark creates a lot of timers (with a zero
1659	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	2411	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1660	which it is), lets them fire exactly once and destroys them again.	2412	which it is), lets them fire exactly once and destroys them again.
1661		2413
1662	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	2414	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1663	distribution.	2415	distribution. It uses the L<AE> interface, which makes a real difference
		2416	for the EV and Perl backends only.
1664		2417
1665	=head3 Explanation of the columns	2418	=head3 Explanation of the columns
1666		2419
1667	I<watcher> is the number of event watchers created/destroyed. Since	2420	I<watcher> is the number of event watchers created/destroyed. Since
1668	different event models feature vastly different performances, each event	2421	different event models feature vastly different performances, each event
…		…
1689	watcher.	2442	watcher.
1690		2443
1691	=head3 Results	2444	=head3 Results
1692		2445
1693	name watchers bytes create invoke destroy comment	2446	name watchers bytes create invoke destroy comment
1694	EV/EV 400000 224 0.47 0.35 0.27 EV native interface	2447	EV/EV 100000 223 0.47 0.43 0.27 EV native interface
1695	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	2448	EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
1696	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal	2449	Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
1697	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation	2450	Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
1698	Event/Event 16000 517 32.20 31.80 0.81 Event native interface	2451	Event/Event 16000 516 31.16 31.84 0.82 Event native interface
1699	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers	2452	Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
1700	IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll	2453	IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
1701	IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll	2454	IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
1702	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour	2455	Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
1703	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers	2456	Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
1704	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event	2457	POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
1705	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select	2458	POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
1706		2459
1707	=head3 Discussion	2460	=head3 Discussion
1708		2461
1709	The benchmark does I<not> measure scalability of the event loop very	2462	The benchmark does I<not> measure scalability of the event loop very
1710	well. For example, a select-based event loop (such as the pure perl one)	2463	well. For example, a select-based event loop (such as the pure perl one)
…		…
1722	benchmark machine, handling an event takes roughly 1600 CPU cycles with	2475	benchmark machine, handling an event takes roughly 1600 CPU cycles with
1723	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU	2476	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
1724	cycles with POE.	2477	cycles with POE.
1725		2478
1726	C<EV> is the sole leader regarding speed and memory use, which are both	2479	C<EV> is the sole leader regarding speed and memory use, which are both
1727	maximal/minimal, respectively. Even when going through AnyEvent, it uses	2480	maximal/minimal, respectively. When using the L<AE> API there is zero
		2481	overhead (when going through the AnyEvent API create is about 5-6 times
		2482	slower, with other times being equal, so still uses far less memory than
1728	far less memory than any other event loop and is still faster than Event	2483	any other event loop and is still faster than Event natively).
1729	natively.
1730		2484
1731	The pure perl implementation is hit in a few sweet spots (both the	2485	The pure perl implementation is hit in a few sweet spots (both the
1732	constant timeout and the use of a single fd hit optimisations in the perl	2486	constant timeout and the use of a single fd hit optimisations in the perl
1733	interpreter and the backend itself). Nevertheless this shows that it	2487	interpreter and the backend itself). Nevertheless this shows that it
1734	adds very little overhead in itself. Like any select-based backend its	2488	adds very little overhead in itself. Like any select-based backend its
…		…
1782	(even when used without AnyEvent), but most event loops have acceptable	2536	(even when used without AnyEvent), but most event loops have acceptable
1783	performance with or without AnyEvent.	2537	performance with or without AnyEvent.
1784		2538
1785	=item * The overhead AnyEvent adds is usually much smaller than the overhead of	2539	=item * The overhead AnyEvent adds is usually much smaller than the overhead of
1786	the actual event loop, only with extremely fast event loops such as EV	2540	the actual event loop, only with extremely fast event loops such as EV
1787	adds AnyEvent significant overhead.	2541	does AnyEvent add significant overhead.
1788		2542
1789	=item * You should avoid POE like the plague if you want performance or	2543	=item * You should avoid POE like the plague if you want performance or
1790	reasonable memory usage.	2544	reasonable memory usage.
1791		2545
1792	=back	2546	=back
…		…
1808	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100	2562	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1809	(1%) are active. This mirrors the activity of large servers with many	2563	(1%) are active. This mirrors the activity of large servers with many
1810	connections, most of which are idle at any one point in time.	2564	connections, most of which are idle at any one point in time.
1811		2565
1812	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	2566	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1813	distribution.	2567	distribution. It uses the L<AE> interface, which makes a real difference
		2568	for the EV and Perl backends only.
1814		2569
1815	=head3 Explanation of the columns	2570	=head3 Explanation of the columns
1816		2571
1817	I<sockets> is the number of sockets, and twice the number of "servers" (as	2572	I<sockets> is the number of sockets, and twice the number of "servers" (as
1818	each server has a read and write socket end).	2573	each server has a read and write socket end).
…		…
1826	a new one that moves the timeout into the future.	2581	a new one that moves the timeout into the future.
1827		2582
1828	=head3 Results	2583	=head3 Results
1829		2584
1830	name sockets create request	2585	name sockets create request
1831	EV 20000 69.01 11.16	2586	EV 20000 62.66 7.99
1832	Perl 20000 73.32 35.87	2587	Perl 20000 68.32 32.64
1833	IOAsync 20000 157.00 98.14 epoll	2588	IOAsync 20000 174.06 101.15 epoll
1834	IOAsync 20000 159.31 616.06 poll	2589	IOAsync 20000 174.67 610.84 poll
1835	Event 20000 212.62 257.32	2590	Event 20000 202.69 242.91
1836	Glib 20000 651.16 1896.30	2591	Glib 20000 557.01 1689.52
1837	POE 20000 349.67 12317.24 uses POE::Loop::Event	2592	POE 20000 341.54 12086.32 uses POE::Loop::Event
1838		2593
1839	=head3 Discussion	2594	=head3 Discussion
1840		2595
1841	This benchmark I<does> measure scalability and overall performance of the	2596	This benchmark I<does> measure scalability and overall performance of the
1842	particular event loop.	2597	particular event loop.
…		…
1968	As you can see, the AnyEvent + EV combination even beats the	2723	As you can see, the AnyEvent + EV combination even beats the
1969	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl	2724	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
1970	backend easily beats IO::Lambda and POE.	2725	backend easily beats IO::Lambda and POE.
1971		2726
1972	And even the 100% non-blocking version written using the high-level (and	2727	And even the 100% non-blocking version written using the high-level (and
1973	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a	2728	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
1974	large margin, even though it does all of DNS, tcp-connect and socket I/O	2729	higher level ("unoptimised") abstractions by a large margin, even though
1975	in a non-blocking way.	2730	it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
1976		2731
1977	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and	2732	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
1978	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are	2733	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
1979	part of the IO::lambda distribution and were used without any changes.	2734	part of the IO::Lambda distribution and were used without any changes.
1980		2735
1981		2736
1982	=head1 SIGNALS	2737	=head1 SIGNALS
1983		2738
1984	AnyEvent currently installs handlers for these signals:	2739	AnyEvent currently installs handlers for these signals:
…		…
1989		2744
1990	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher	2745	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
1991	emulation for event loops that do not support them natively. Also, some	2746	emulation for event loops that do not support them natively. Also, some
1992	event loops install a similar handler.	2747	event loops install a similar handler.
1993		2748
1994	If, when AnyEvent is loaded, SIGCHLD is set to IGNORE, then AnyEvent will	2749	Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
1995	reset it to default, to avoid losing child exit statuses.	2750	AnyEvent will reset it to default, to avoid losing child exit statuses.
1996		2751
1997	=item SIGPIPE	2752	=item SIGPIPE
1998		2753
1999	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>	2754	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
2000	when AnyEvent gets loaded.	2755	when AnyEvent gets loaded.
…		…
2018	if $SIG{CHLD} eq 'IGNORE';	2773	if $SIG{CHLD} eq 'IGNORE';
2019		2774
2020	$SIG{PIPE} = sub { }	2775	$SIG{PIPE} = sub { }
2021	unless defined $SIG{PIPE};	2776	unless defined $SIG{PIPE};
2022		2777
		2778	=head1 RECOMMENDED/OPTIONAL MODULES
		2779
		2780	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
		2781	its built-in modules) are required to use it.
		2782
		2783	That does not mean that AnyEvent won't take advantage of some additional
		2784	modules if they are installed.
		2785
		2786	This section explains which additional modules will be used, and how they
		2787	affect AnyEvent's operation.
		2788
		2789	=over 4
		2790
		2791	=item L<Async::Interrupt>
		2792
		2793	This slightly arcane module is used to implement fast signal handling: To
		2794	my knowledge, there is no way to do completely race-free and quick
		2795	signal handling in pure perl. To ensure that signals still get
		2796	delivered, AnyEvent will start an interval timer to wake up perl (and
		2797	catch the signals) with some delay (default is 10 seconds, look for
		2798	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
		2799
		2800	If this module is available, then it will be used to implement signal
		2801	catching, which means that signals will not be delayed, and the event loop
		2802	will not be interrupted regularly, which is more efficient (and good for
		2803	battery life on laptops).
		2804
		2805	This affects not just the pure-perl event loop, but also other event loops
		2806	that have no signal handling on their own (e.g. Glib, Tk, Qt).
		2807
		2808	Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
		2809	and either employ their own workarounds (POE) or use AnyEvent's workaround
		2810	(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
		2811	does nothing for those backends.
		2812
		2813	=item L<EV>
		2814
		2815	This module isn't really "optional", as it is simply one of the backend
		2816	event loops that AnyEvent can use. However, it is simply the best event
		2817	loop available in terms of features, speed and stability: It supports
		2818	the AnyEvent API optimally, implements all the watcher types in XS, does
		2819	automatic timer adjustments even when no monotonic clock is available,
		2820	can take avdantage of advanced kernel interfaces such as C<epoll> and
		2821	C<kqueue>, and is the fastest backend I<by far>. You can even embed
		2822	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
		2823
		2824	If you only use backends that rely on another event loop (e.g. C<Tk>),
		2825	then this module will do nothing for you.
		2826
		2827	=item L<Guard>
		2828
		2829	The guard module, when used, will be used to implement
		2830	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
		2831	lot less memory), but otherwise doesn't affect guard operation much. It is
		2832	purely used for performance.
		2833
		2834	=item L<JSON> and L<JSON::XS>
		2835
		2836	One of these modules is required when you want to read or write JSON data
		2837	via L<AnyEvent::Handle>. L<JSON> is also written in pure-perl, but can take
		2838	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
		2839
		2840	=item L<Net::SSLeay>
		2841
		2842	Implementing TLS/SSL in Perl is certainly interesting, but not very
		2843	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
		2844	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
		2845
		2846	=item L<Time::HiRes>
		2847
		2848	This module is part of perl since release 5.008. It will be used when the
		2849	chosen event library does not come with a timing source of its own. The
		2850	pure-perl event loop (L<AnyEvent::Loop>) will additionally load it to
		2851	try to use a monotonic clock for timing stability.
		2852
		2853	=back
		2854
		2855
2023	=head1 FORK	2856	=head1 FORK
2024		2857
2025	Most event libraries are not fork-safe. The ones who are usually are	2858	Most event libraries are not fork-safe. The ones who are usually are
2026	because they rely on inefficient but fork-safe C<select> or C<poll>	2859	because they rely on inefficient but fork-safe C<select> or C<poll> calls
2027	calls. Only L<EV> is fully fork-aware.	2860	- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
		2861	are usually badly thought-out hacks that are incompatible with fork in
		2862	one way or another. Only L<EV> is fully fork-aware and ensures that you
		2863	continue event-processing in both parent and child (or both, if you know
		2864	what you are doing).
		2865
		2866	This means that, in general, you cannot fork and do event processing in
		2867	the child if the event library was initialised before the fork (which
		2868	usually happens when the first AnyEvent watcher is created, or the library
		2869	is loaded).
2028		2870
2029	If you have to fork, you must either do so I<before> creating your first	2871	If you have to fork, you must either do so I<before> creating your first
2030	watcher OR you must not use AnyEvent at all in the child.	2872	watcher OR you must not use AnyEvent at all in the child OR you must do
		2873	something completely out of the scope of AnyEvent.
		2874
		2875	The problem of doing event processing in the parent I<and> the child
		2876	is much more complicated: even for backends that I<are> fork-aware or
		2877	fork-safe, their behaviour is not usually what you want: fork clones all
		2878	watchers, that means all timers, I/O watchers etc. are active in both
		2879	parent and child, which is almost never what you want. USing C<exec>
		2880	to start worker children from some kind of manage rprocess is usually
		2881	preferred, because it is much easier and cleaner, at the expense of having
		2882	to have another binary.
2031		2883
2032		2884
2033	=head1 SECURITY CONSIDERATIONS	2885	=head1 SECURITY CONSIDERATIONS
2034		2886
2035	AnyEvent can be forced to load any event model via	2887	AnyEvent can be forced to load any event model via
…		…
2065	pronounced).	2917	pronounced).
2066		2918
2067		2919
2068	=head1 SEE ALSO	2920	=head1 SEE ALSO
2069		2921
2070	Utility functions: L<AnyEvent::Util>.	2922	Tutorial/Introduction: L<AnyEvent::Intro>.
2071		2923
2072	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,	2924	FAQ: L<AnyEvent::FAQ>.
2073	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2925
		2926	Utility functions: L<AnyEvent::Util> (misc. grab-bag), L<AnyEvent::Log>
		2927	(simply logging).
		2928
		2929	Development/Debugging: L<AnyEvent::Strict> (stricter checking),
		2930	L<AnyEvent::Debug> (interactive shell, watcher tracing).
		2931
		2932	Supported event modules: L<AnyEvent::Loop>, L<EV>, L<EV::Glib>,
		2933	L<Glib::EV>, L<Event>, L<Glib::Event>, L<Glib>, L<Tk>, L<Event::Lib>,
		2934	L<Qt>, L<POE>, L<FLTK>.
2074		2935
2075	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2936	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
2076	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2937	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
2077	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2938	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
		2939	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>,
2078	L<AnyEvent::Impl::POE>.	2940	L<AnyEvent::Impl::FLTK>.
2079		2941
2080	Non-blocking file handles, sockets, TCP clients and	2942	Non-blocking handles, pipes, stream sockets, TCP clients and
2081	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.	2943	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2082		2944
2083	Asynchronous DNS: L<AnyEvent::DNS>.	2945	Asynchronous DNS: L<AnyEvent::DNS>.
2084		2946
2085	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,	2947	Thread support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>.
2086		2948
2087	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.	2949	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::IRC>,
		2950	L<AnyEvent::HTTP>.
2088		2951
2089		2952
2090	=head1 AUTHOR	2953	=head1 AUTHOR
2091		2954
2092	Marc Lehmann <schmorp@schmorp.de>	2955	Marc Lehmann <schmorp@schmorp.de>

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