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Revision 1.330 by root, Tue Aug 31 00:59:55 2010 UTC

1	=head1 NAME	1	=head1 NAME
2		2
3	AnyEvent - provide framework for multiple event loops	3	AnyEvent - the DBI of event loop programming
4		4
5	EV, Event, Glib, Tk, Perl, Event::Lib, Qt and POE are various supported	5	EV, Event, Glib, Tk, Perl, Event::Lib, Irssi, rxvt-unicode, IO::Async, Qt
6	event loops.	6	and POE are various supported event loops/environments.
7		7
8	=head1 SYNOPSIS	8	=head1 SYNOPSIS
9		9
10	use AnyEvent;	10	use AnyEvent;
11		11
		12	# if you prefer function calls, look at the AE manpage for
		13	# an alternative API.
		14
12	# file descriptor readable	15	# file handle or descriptor readable
13	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });	16	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });
14		17
15	# one-shot or repeating timers	18	# one-shot or repeating timers
16	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });	19	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
17	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...	20	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...);
18		21
19	print AnyEvent->now; # prints current event loop time	22	print AnyEvent->now; # prints current event loop time
20	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.	23	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
21		24
22	# POSIX signal	25	# POSIX signal
…		…
40	=head1 INTRODUCTION/TUTORIAL	43	=head1 INTRODUCTION/TUTORIAL
41		44
42	This manpage is mainly a reference manual. If you are interested	45	This manpage is mainly a reference manual. If you are interested
43	in a tutorial or some gentle introduction, have a look at the	46	in a tutorial or some gentle introduction, have a look at the
44	L<AnyEvent::Intro> manpage.	47	L<AnyEvent::Intro> manpage.
		48
		49	=head1 SUPPORT
		50
		51	There is a mailinglist for discussing all things AnyEvent, and an IRC
		52	channel, too.
		53
		54	See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software
		55	Repository>, at L<http://anyevent.schmorp.de>, for more info.
45		56
46	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)	57	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
47		58
48	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen	59	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
49	nowadays. So what is different about AnyEvent?	60	nowadays. So what is different about AnyEvent?
…		…
65	module users into the same thing by forcing them to use the same event	76	module users into the same thing by forcing them to use the same event
66	model you use.	77	model you use.
67		78
68	For modules like POE or IO::Async (which is a total misnomer as it is	79	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	80	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	81	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	82	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	83	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.	84	module are I<also> forced to use the same event loop you use.
74		85
75	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works	86	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
76	fine. AnyEvent + Tk works fine etc. etc. but none of these work together	87	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	88	with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if
78	your module uses one of those, every user of your module has to use it,	89	your module uses one of those, every user of your module has to use it,
79	too. But if your module uses AnyEvent, it works transparently with all	90	too. But if your module uses AnyEvent, it works transparently with all
80	event models it supports (including stuff like IO::Async, as long as those	91	event models it supports (including stuff like IO::Async, as long as those
81	use one of the supported event loops. It is trivial to add new event loops	92	use one of the supported event loops. It is easy to add new event loops
82	to AnyEvent, too, so it is future-proof).	93	to AnyEvent, too, so it is future-proof).
83		94
84	In addition to being free of having to use I<the one and only true event	95	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	96	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	97	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	98	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	99	offering the functionality that is necessary, in as thin as a wrapper as
89	technically possible.	100	technically possible.
90		101
91	Of course, AnyEvent comes with a big (and fully optional!) toolbox	102	Of course, AnyEvent comes with a big (and fully optional!) toolbox
92	of useful functionality, such as an asynchronous DNS resolver, 100%	103	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	109	useful) and you want to force your users to use the one and only event
99	model, you should I<not> use this module.	110	model, you should I<not> use this module.
100		111
101	=head1 DESCRIPTION	112	=head1 DESCRIPTION
102		113
103	L<AnyEvent> provides an identical interface to multiple event loops. This	114	L<AnyEvent> provides a uniform interface to various event loops. This
104	allows module authors to utilise an event loop without forcing module	115	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	116	module users to use a specific event loop implementation (since more
106	peacefully at any one time).	117	than one event loop cannot coexist peacefully).
107		118
108	The interface itself is vaguely similar, but not identical to the L<Event>	119	The interface itself is vaguely similar, but not identical to the L<Event>
109	module.	120	module.
110		121
111	During the first call of any watcher-creation method, the module tries	122	During the first call of any watcher-creation method, the module tries
…		…
127	use AnyEvent;	138	use AnyEvent;
128		139
129	# .. AnyEvent will likely default to Tk	140	# .. AnyEvent will likely default to Tk
130		141
131	The I<likely> means that, if any module loads another event model and	142	The I<likely> means that, if any module loads another event model and
132	starts using it, all bets are off. Maybe you should tell their authors to	143	starts using it, all bets are off - this case should be very rare though,
133	use AnyEvent so their modules work together with others seamlessly...	144	as very few modules hardcode event loops without announcing this very
		145	loudly.
134		146
135	The pure-perl implementation of AnyEvent is called	147	The pure-perl implementation of AnyEvent is called
136	C<AnyEvent::Impl::Perl>. Like other event modules you can load it	148	C<AnyEvent::Impl::Perl>. Like other event modules you can load it
137	explicitly and enjoy the high availability of that event loop :)	149	explicitly and enjoy the high availability of that event loop :)
138		150
…		…
147	callback when the event occurs (of course, only when the event model	159	callback when the event occurs (of course, only when the event model
148	is in control).	160	is in control).
149		161
150	Note that B<callbacks must not permanently change global variables>	162	Note that B<callbacks must not permanently change global variables>
151	potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<	163	potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<
152	callbacks must not C<die> >>. The former is good programming practise in	164	callbacks must not C<die> >>. The former is good programming practice in
153	Perl and the latter stems from the fact that exception handling differs	165	Perl and the latter stems from the fact that exception handling differs
154	widely between event loops.	166	widely between event loops.
155		167
156	To disable the watcher you have to destroy it (e.g. by setting the	168	To disable a watcher you have to destroy it (e.g. by setting the
157	variable you store it in to C<undef> or otherwise deleting all references	169	variable you store it in to C<undef> or otherwise deleting all references
158	to it).	170	to it).
159		171
160	All watchers are created by calling a method on the C<AnyEvent> class.	172	All watchers are created by calling a method on the C<AnyEvent> class.
161		173
162	Many watchers either are used with "recursion" (repeating timers for	174	Many watchers either are used with "recursion" (repeating timers for
163	example), or need to refer to their watcher object in other ways.	175	example), or need to refer to their watcher object in other ways.
164		176
165	An any way to achieve that is this pattern:	177	One way to achieve that is this pattern:
166		178
167	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {	179	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
168	# you can use $w here, for example to undef it	180	# you can use $w here, for example to undef it
169	undef $w;	181	undef $w;
170	});	182	});
…		…
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
…		…
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
…		…
392		469
393	There is a slight catch to child watchers, however: you usually start them	470	There is a slight catch to child watchers, however: you usually start them
394	I<after> the child process was created, and this means the process could	471	I<after> the child process was created, and this means the process could
395	have exited already (and no SIGCHLD will be sent anymore).	472	have exited already (and no SIGCHLD will be sent anymore).
396		473
397	Not all event models handle this correctly (POE doesn't), but even for	474	Not all event models handle this correctly (neither POE nor IO::Async do,
		475	see their AnyEvent::Impl manpages for details), but even for event models
398	event models that I<do> handle this correctly, they usually need to be	476	that I<do> handle this correctly, they usually need to be loaded before
399	loaded before the process exits (i.e. before you fork in the first place).	477	the process exits (i.e. before you fork in the first place). AnyEvent's
		478	pure perl event loop handles all cases correctly regardless of when you
		479	start the watcher.
400		480
401	This means you cannot create a child watcher as the very first thing in an	481	This means you cannot create a child watcher as the very first
402	AnyEvent program, you I<have> to create at least one watcher before you	482	thing in an AnyEvent program, you I<have> to create at least one
403	C<fork> the child (alternatively, you can call C<AnyEvent::detect>).	483	watcher before you C<fork> the child (alternatively, you can call
		484	C<AnyEvent::detect>).
		485
		486	As most event loops do not support waiting for child events, they will be
		487	emulated by AnyEvent in most cases, in which the latency and race problems
		488	mentioned in the description of signal watchers apply.
404		489
405	Example: fork a process and wait for it	490	Example: fork a process and wait for it
406		491
407	my $done = AnyEvent->condvar;	492	my $done = AnyEvent->condvar;
408		493
…		…
420	# do something else, then wait for process exit	505	# do something else, then wait for process exit
421	$done->recv;	506	$done->recv;
422		507
423	=head2 IDLE WATCHERS	508	=head2 IDLE WATCHERS
424		509
425	Sometimes there is a need to do something, but it is not so important	510	$w = AnyEvent->idle (cb => <callback>);
426	to do it instantly, but only when there is nothing better to do. This
427	"nothing better to do" is usually defined to be "no other events need
428	attention by the event loop".
429		511
430	Idle watchers ideally get invoked when the event loop has nothing	512	This will repeatedly invoke the callback after the process becomes idle,
431	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.
432	events. Instead of blocking, the idle watcher is invoked.
433		514
434	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
435	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
436	will simply call the callback "from time to time".	526	will simply call the callback "from time to time".
437		527
438	Example: read lines from STDIN, but only process them when the	528	Example: read lines from STDIN, but only process them when the
439	program is otherwise idle:	529	program is otherwise idle:
…		…
455	});	545	});
456	});	546	});
457		547
458	=head2 CONDITION VARIABLES	548	=head2 CONDITION VARIABLES
459		549
		550	$cv = AnyEvent->condvar;
		551
		552	$cv->send (<list>);
		553	my @res = $cv->recv;
		554
460	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
461	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
462	will actively watch for new events and call your callbacks.	557	will actively watch for new events and call your callbacks.
463		558
464	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
465	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).
466		561
467	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
468	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.
469		566
470	Condition variables can be created by calling the C<< AnyEvent->condvar	567	Condition variables can be created by calling the C<< AnyEvent->condvar
471	>> method, usually without arguments. The only argument pair allowed is	568	>> method, usually without arguments. The only argument pair allowed is
472
473	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
474	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
475	the results).	571	the results).
476		572
477	After creation, the condition variable is "false" until it becomes "true"	573	After creation, the condition variable is "false" until it becomes "true"
478	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
479	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<<
480	->send >> method).	576	->send >> method).
481		577
482	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
483	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:
484	in time where multiple outstanding events have been processed. And yet	580
485	another way to call them is transactions - each condition variable can be	581	=over 4
486	used to represent a transaction, which finishes at some point and delivers	582
487	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
488		601
489	Condition variables are very useful to signal that something has finished,	602	Condition variables are very useful to signal that something has finished,
490	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,
491	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
492	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
…		…
505		618
506	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
507	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
508	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
509	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
510	it's C<new> method in your own C<new> method.	623	its C<new> method in your own C<new> method.
511		624
512	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
513	eventually calls C<< -> send >>, and the "consumer side", which waits	626	eventually calls C<< -> send >>, and the "consumer side", which waits
514	for the send to occur.	627	for the send to occur.
515		628
516	Example: wait for a timer.	629	Example: wait for a timer.
517		630
518	# wait till the result is ready	631	# condition: "wait till the timer is fired"
519	my $result_ready = AnyEvent->condvar;	632	my $timer_fired = AnyEvent->condvar;
520		633
521	# do something such as adding a timer	634	# create the timer - we could wait for, say
522	# or socket watcher the calls $result_ready->send	635	# a handle becomign ready, or even an
523	# when the "result" is ready.	636	# AnyEvent::HTTP request to finish, but
524	# in this case, we simply use a timer:	637	# in this case, we simply use a timer:
525	my $w = AnyEvent->timer (	638	my $w = AnyEvent->timer (
526	after => 1,	639	after => 1,
527	cb => sub { $result_ready->send },	640	cb => sub { $timer_fired->send },
528	);	641	);
529		642
530	# this "blocks" (while handling events) till the callback	643	# this "blocks" (while handling events) till the callback
531	# calls send	644	# calls ->send
532	$result_ready->recv;	645	$timer_fired->recv;
533		646
534	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
535	condition variables are also code references.	648	variables are also callable directly.
536		649
537	my $done = AnyEvent->condvar;	650	my $done = AnyEvent->condvar;
538	my $delay = AnyEvent->timer (after => 5, cb => $done);	651	my $delay = AnyEvent->timer (after => 5, cb => $done);
539	$done->recv;	652	$done->recv;
540		653
…		…
546		659
547	...	660	...
548		661
549	my @info = $couchdb->info->recv;	662	my @info = $couchdb->info->recv;
550		663
551	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
552	results are available:	665	results are available:
553		666
554	$couchdb->info->cb (sub {	667	$couchdb->info->cb (sub {
555	my @info = $_[0]->recv;	668	my @info = $_[0]->recv;
556	});	669	});
…		…
574	immediately from within send.	687	immediately from within send.
575		688
576	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
577	future C<< ->recv >> calls.	690	future C<< ->recv >> calls.
578		691
579	Condition variables are overloaded so one can call them directly	692	Condition variables are overloaded so one can call them directly (as if
580	(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
581	C<send>. Note, however, that many C-based event loops do not handle	694	C<send>.
582	overloading, so as tempting as it may be, passing a condition variable
583	instead of a callback does not work. Both the pure perl and EV loops
584	support overloading, however, as well as all functions that use perl to
585	invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
586	example).
587		695
588	=item $cv->croak ($error)	696	=item $cv->croak ($error)
589		697
590	Similar to send, but causes all call's to C<< ->recv >> to invoke	698	Similar to send, but causes all calls to C<< ->recv >> to invoke
591	C<Carp::croak> with the given error message/object/scalar.	699	C<Carp::croak> with the given error message/object/scalar.
592		700
593	This can be used to signal any errors to the condition variable	701	This can be used to signal any errors to the condition variable
594	user/consumer.	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.
595		707
596	=item $cv->begin ([group callback])	708	=item $cv->begin ([group callback])
597		709
598	=item $cv->end	710	=item $cv->end
599
600	These two methods are EXPERIMENTAL and MIGHT CHANGE.
601		711
602	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
603	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
604	to use a condition variable for the whole process.	714	to use a condition variable for the whole process.
605		715
606	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
607	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
608	>>, 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
609	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
610	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.
611		722
612	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:
613		730
614	my $cv = AnyEvent->condvar;	731	my $cv = AnyEvent->condvar;
615		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
616	my %result;	757	my %result;
617	$cv->begin (sub { $cv->send (\%result) });	758	$cv->begin (sub { shift->send (\%result) });
618		759
619	for my $host (@list_of_hosts) {	760	for my $host (@list_of_hosts) {
620	$cv->begin;	761	$cv->begin;
621	ping_host_then_call_callback $host, sub {	762	ping_host_then_call_callback $host, sub {
622	$result{$host} = ...;	763	$result{$host} = ...;
…		…
637	loop, which serves two important purposes: first, it sets the callback	778	loop, which serves two important purposes: first, it sets the callback
638	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
639	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
640	doesn't execute once).	781	doesn't execute once).
641		782
642	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
643	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
644	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
645	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>.
646		788
647	=back	789	=back
648		790
649	=head3 METHODS FOR CONSUMERS	791	=head3 METHODS FOR CONSUMERS
650		792
…		…
654	=over 4	796	=over 4
655		797
656	=item $cv->recv	798	=item $cv->recv
657		799
658	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak	800	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
659	>> methods have been called on c<$cv>, while servicing other watchers	801	>> methods have been called on C<$cv>, while servicing other watchers
660	normally.	802	normally.
661		803
662	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
663	will return immediately.	805	will return immediately.
664		806
…		…
666	function will call C<croak>.	808	function will call C<croak>.
667		809
668	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,
669	in scalar context only the first one will be returned.	811	in scalar context only the first one will be returned.
670		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
671	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
672	(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
673	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
674	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
675	condition variables with some kind of request results and supporting	824	condition variables with some kind of request results and supporting
676	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,
677	while still supporting blocking waits if the caller so desires).	826	while still supporting blocking waits if the caller so desires).
678		827
679	Another reason I<never> to C<< ->recv >> in a module is that you cannot
680	sensibly have two C<< ->recv >>'s in parallel, as that would require
681	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
682	can supply.
683
684	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
685	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
686	versions and also integrates coroutines into AnyEvent, making blocking
687	C<< ->recv >> calls perfectly safe as long as they are done from another
688	coroutine (one that doesn't run the event loop).
689
690	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
691	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
692	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
693	waits otherwise.	831	waits otherwise.
694		832
695	=item $bool = $cv->ready	833	=item $bool = $cv->ready
…		…
701		839
702	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
703	replaces it before doing so.	841	replaces it before doing so.
704		842
705	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
706	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
707	variable itself. Calling C<recv> inside the callback or at any later time	845	condition variable itself. If the condition is already true, the
708	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.
709		848
710	=back	849	=back
711		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 implementation, 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
		882	=item Backends with special needs.
		883
		884	Qt requires the Qt::Application to be instantiated first, but will
		885	otherwise be picked up automatically. As long as the main program
		886	instantiates the application before any AnyEvent watchers are created,
		887	everything should just work.
		888
		889	AnyEvent::Impl::Qt based on Qt.
		890
		891	Support for IO::Async can only be partial, as it is too broken and
		892	architecturally limited to even support the AnyEvent API. It also
		893	is the only event loop that needs the loop to be set explicitly, so
		894	it can only be used by a main program knowing about AnyEvent. See
		895	L<AnyEvent::Impl::IOAsync> for the gory details.
		896
		897	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
		898
		899	=item Event loops that are indirectly supported via other backends.
		900
		901	Some event loops can be supported via other modules:
		902
		903	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
		904
		905	B<WxWidgets> has no support for watching file handles. However, you can
		906	use WxWidgets through the POE adaptor, as POE has a Wx backend that simply
		907	polls 20 times per second, which was considered to be too horrible to even
		908	consider for AnyEvent.
		909
		910	B<Prima> is not supported as nobody seems to be using it, but it has a POE
		911	backend, so it can be supported through POE.
		912
		913	AnyEvent knows about both L<Prima> and L<Wx>, however, and will try to
		914	load L<POE> when detecting them, in the hope that POE will pick them up,
		915	in which case everything will be automatic.
		916
		917	=back
		918
712	=head1 GLOBAL VARIABLES AND FUNCTIONS	919	=head1 GLOBAL VARIABLES AND FUNCTIONS
713		920
		921	These are not normally required to use AnyEvent, but can be useful to
		922	write AnyEvent extension modules.
		923
714	=over 4	924	=over 4
715		925
716	=item $AnyEvent::MODEL	926	=item $AnyEvent::MODEL
717		927
718	Contains C<undef> until the first watcher is being created. Then it	928	Contains C<undef> until the first watcher is being created, before the
		929	backend has been autodetected.
		930
719	contains the event model that is being used, which is the name of the	931	Afterwards it contains the event model that is being used, which is the
720	Perl class implementing the model. This class is usually one of the	932	name of the Perl class implementing the model. This class is usually one
721	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	933	of the C<AnyEvent::Impl::xxx> modules, but can be any other class in the
722	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	934	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
723		935	will be C<urxvt::anyevent>).
724	The known classes so far are:
725
726	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
727	AnyEvent::Impl::Event based on Event, second best choice.
728	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
729	AnyEvent::Impl::Glib based on Glib, third-best choice.
730	AnyEvent::Impl::Tk based on Tk, very bad choice.
731	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
732	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
733	AnyEvent::Impl::POE based on POE, not generic enough for full support.
734
735	There is no support for WxWidgets, as WxWidgets has no support for
736	watching file handles. However, you can use WxWidgets through the
737	POE Adaptor, as POE has a Wx backend that simply polls 20 times per
738	second, which was considered to be too horrible to even consider for
739	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
740	it's adaptor.
741
742	AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
743	autodetecting them.
744		936
745	=item AnyEvent::detect	937	=item AnyEvent::detect
746		938
747	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	939	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
748	if necessary. You should only call this function right before you would	940	if necessary. You should only call this function right before you would
749	have created an AnyEvent watcher anyway, that is, as late as possible at	941	have created an AnyEvent watcher anyway, that is, as late as possible at
750	runtime.	942	runtime, and not e.g. during initialisation of your module.
		943
		944	If you need to do some initialisation before AnyEvent watchers are
		945	created, use C<post_detect>.
751		946
752	=item $guard = AnyEvent::post_detect { BLOCK }	947	=item $guard = AnyEvent::post_detect { BLOCK }
753		948
754	Arranges for the code block to be executed as soon as the event model is	949	Arranges for the code block to be executed as soon as the event model is
755	autodetected (or immediately if this has already happened).	950	autodetected (or immediately if that has already happened).
		951
		952	The block will be executed I<after> the actual backend has been detected
		953	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
		954	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
		955	other initialisations - see the sources of L<AnyEvent::Strict> or
		956	L<AnyEvent::AIO> to see how this is used.
		957
		958	The most common usage is to create some global watchers, without forcing
		959	event module detection too early, for example, L<AnyEvent::AIO> creates
		960	and installs the global L<IO::AIO> watcher in a C<post_detect> block to
		961	avoid autodetecting the event module at load time.
756		962
757	If called in scalar or list context, then it creates and returns an object	963	If called in scalar or list context, then it creates and returns an object
758	that automatically removes the callback again when it is destroyed. See	964	that automatically removes the callback again when it is destroyed (or
		965	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
759	L<Coro::BDB> for a case where this is useful.	966	a case where this is useful.
		967
		968	Example: Create a watcher for the IO::AIO module and store it in
		969	C<$WATCHER>, but do so only do so after the event loop is initialised.
		970
		971	our WATCHER;
		972
		973	my $guard = AnyEvent::post_detect {
		974	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
		975	};
		976
		977	# the ||= is important in case post_detect immediately runs the block,
		978	# as to not clobber the newly-created watcher. assigning both watcher and
		979	# post_detect guard to the same variable has the advantage of users being
		980	# able to just C<undef $WATCHER> if the watcher causes them grief.
		981
		982	$WATCHER ||= $guard;
760		983
761	=item @AnyEvent::post_detect	984	=item @AnyEvent::post_detect
762		985
763	If there are any code references in this array (you can C<push> to it	986	If there are any code references in this array (you can C<push> to it
764	before or after loading AnyEvent), then they will called directly after	987	before or after loading AnyEvent), then they will be called directly
765	the event loop has been chosen.	988	after the event loop has been chosen.
766		989
767	You should check C<$AnyEvent::MODEL> before adding to this array, though:	990	You should check C<$AnyEvent::MODEL> before adding to this array, though:
768	if it contains a true value then the event loop has already been detected,	991	if it is defined then the event loop has already been detected, and the
769	and the array will be ignored.	992	array will be ignored.
770		993
771	Best use C<AnyEvent::post_detect { BLOCK }> instead.	994	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
		995	it, as it takes care of these details.
		996
		997	This variable is mainly useful for modules that can do something useful
		998	when AnyEvent is used and thus want to know when it is initialised, but do
		999	not need to even load it by default. This array provides the means to hook
		1000	into AnyEvent passively, without loading it.
		1001
		1002	Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used
		1003	together, you could put this into Coro (this is the actual code used by
		1004	Coro to accomplish this):
		1005
		1006	if (defined $AnyEvent::MODEL) {
		1007	# AnyEvent already initialised, so load Coro::AnyEvent
		1008	require Coro::AnyEvent;
		1009	} else {
		1010	# AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
		1011	# as soon as it is
		1012	push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
		1013	}
772		1014
773	=back	1015	=back
774		1016
775	=head1 WHAT TO DO IN A MODULE	1017	=head1 WHAT TO DO IN A MODULE
776		1018
…		…
787	because it will stall the whole program, and the whole point of using	1029	because it will stall the whole program, and the whole point of using
788	events is to stay interactive.	1030	events is to stay interactive.
789		1031
790	It is fine, however, to call C<< ->recv >> when the user of your module	1032	It is fine, however, to call C<< ->recv >> when the user of your module
791	requests it (i.e. if you create a http request object ad have a method	1033	requests it (i.e. if you create a http request object ad have a method
792	called C<results> that returns the results, it should call C<< ->recv >>	1034	called C<results> that returns the results, it may call C<< ->recv >>
793	freely, as the user of your module knows what she is doing. always).	1035	freely, as the user of your module knows what she is doing. Always).
794		1036
795	=head1 WHAT TO DO IN THE MAIN PROGRAM	1037	=head1 WHAT TO DO IN THE MAIN PROGRAM
796		1038
797	There will always be a single main program - the only place that should	1039	There will always be a single main program - the only place that should
798	dictate which event model to use.	1040	dictate which event model to use.
799		1041
800	If it doesn't care, it can just "use AnyEvent" and use it itself, or not	1042	If the program is not event-based, it need not do anything special, even
801	do anything special (it does not need to be event-based) and let AnyEvent	1043	when it depends on a module that uses an AnyEvent. If the program itself
802	decide which implementation to chose if some module relies on it.	1044	uses AnyEvent, but does not care which event loop is used, all it needs
		1045	to do is C<use AnyEvent>. In either case, AnyEvent will choose the best
		1046	available loop implementation.
803		1047
804	If the main program relies on a specific event model - for example, in	1048	If the main program relies on a specific event model - for example, in
805	Gtk2 programs you have to rely on the Glib module - you should load the	1049	Gtk2 programs you have to rely on the Glib module - you should load the
806	event module before loading AnyEvent or any module that uses it: generally	1050	event module before loading AnyEvent or any module that uses it: generally
807	speaking, you should load it as early as possible. The reason is that	1051	speaking, you should load it as early as possible. The reason is that
808	modules might create watchers when they are loaded, and AnyEvent will	1052	modules might create watchers when they are loaded, and AnyEvent will
809	decide on the event model to use as soon as it creates watchers, and it	1053	decide on the event model to use as soon as it creates watchers, and it
810	might chose the wrong one unless you load the correct one yourself.	1054	might choose the wrong one unless you load the correct one yourself.
811		1055
812	You can chose to use a pure-perl implementation by loading the	1056	You can chose to use a pure-perl implementation by loading the
813	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour	1057	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour
814	everywhere, but letting AnyEvent chose the model is generally better.	1058	everywhere, but letting AnyEvent chose the model is generally better.
815		1059
…		…
831		1075
832		1076
833	=head1 OTHER MODULES	1077	=head1 OTHER MODULES
834		1078
835	The following is a non-exhaustive list of additional modules that use	1079	The following is a non-exhaustive list of additional modules that use
836	AnyEvent and can therefore be mixed easily with other AnyEvent modules	1080	AnyEvent as a client and can therefore be mixed easily with other AnyEvent
837	in the same program. Some of the modules come with AnyEvent, some are	1081	modules and other event loops in the same program. Some of the modules
838	available via CPAN.	1082	come as part of AnyEvent, the others are available via CPAN.
839		1083
840	=over 4	1084	=over 4
841		1085
842	=item L<AnyEvent::Util>	1086	=item L<AnyEvent::Util>
843		1087
844	Contains various utility functions that replace often-used but blocking	1088	Contains various utility functions that replace often-used blocking
845	functions such as C<inet_aton> by event-/callback-based versions.	1089	functions such as C<inet_aton> with event/callback-based versions.
846		1090
847	=item L<AnyEvent::Socket>	1091	=item L<AnyEvent::Socket>
848		1092
849	Provides various utility functions for (internet protocol) sockets,	1093	Provides various utility functions for (internet protocol) sockets,
850	addresses and name resolution. Also functions to create non-blocking tcp	1094	addresses and name resolution. Also functions to create non-blocking tcp
…		…
852		1096
853	=item L<AnyEvent::Handle>	1097	=item L<AnyEvent::Handle>
854		1098
855	Provide read and write buffers, manages watchers for reads and writes,	1099	Provide read and write buffers, manages watchers for reads and writes,
856	supports raw and formatted I/O, I/O queued and fully transparent and	1100	supports raw and formatted I/O, I/O queued and fully transparent and
857	non-blocking SSL/TLS.	1101	non-blocking SSL/TLS (via L<AnyEvent::TLS>).
858		1102
859	=item L<AnyEvent::DNS>	1103	=item L<AnyEvent::DNS>
860		1104
861	Provides rich asynchronous DNS resolver capabilities.	1105	Provides rich asynchronous DNS resolver capabilities.
862		1106
		1107	=item L<AnyEvent::HTTP>, L<AnyEvent::IRC>, L<AnyEvent::XMPP>, L<AnyEvent::GPSD>, L<AnyEvent::IGS>, L<AnyEvent::FCP>
		1108
		1109	Implement event-based interfaces to the protocols of the same name (for
		1110	the curious, IGS is the International Go Server and FCP is the Freenet
		1111	Client Protocol).
		1112
		1113	=item L<AnyEvent::Handle::UDP>
		1114
		1115	Here be danger!
		1116
		1117	As Pauli would put it, "Not only is it not right, it's not even wrong!" -
		1118	there are so many things wrong with AnyEvent::Handle::UDP, most notably
		1119	its use of a stream-based API with a protocol that isn't streamable, that
		1120	the only way to improve it is to delete it.
		1121
		1122	It features data corruption (but typically only under load) and general
		1123	confusion. On top, the author is not only clueless about UDP but also
		1124	fact-resistant - some gems of his understanding: "connect doesn't work
		1125	with UDP", "UDP packets are not IP packets", "UDP only has datagrams, not
		1126	packets", "I don't need to implement proper error checking as UDP doesn't
		1127	support error checking" and so on - he doesn't even understand what's
		1128	wrong with his module when it is explained to him.
		1129
863	=item L<AnyEvent::HTTP>	1130	=item L<AnyEvent::DBI>
864		1131
865	A simple-to-use HTTP library that is capable of making a lot of concurrent	1132	Executes L<DBI> requests asynchronously in a proxy process for you,
866	HTTP requests.	1133	notifying you in an event-based way when the operation is finished.
		1134
		1135	=item L<AnyEvent::AIO>
		1136
		1137	Truly asynchronous (as opposed to non-blocking) I/O, should be in the
		1138	toolbox of every event programmer. AnyEvent::AIO transparently fuses
		1139	L<IO::AIO> and AnyEvent together, giving AnyEvent access to event-based
		1140	file I/O, and much more.
867		1141
868	=item L<AnyEvent::HTTPD>	1142	=item L<AnyEvent::HTTPD>
869		1143
870	Provides a simple web application server framework.	1144	A simple embedded webserver.
871		1145
872	=item L<AnyEvent::FastPing>	1146	=item L<AnyEvent::FastPing>
873		1147
874	The fastest ping in the west.	1148	The fastest ping in the west.
875		1149
876	=item L<AnyEvent::DBI>
877
878	Executes L<DBI> requests asynchronously in a proxy process.
879
880	=item L<AnyEvent::AIO>
881
882	Truly asynchronous I/O, should be in the toolbox of every event
883	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
884	together.
885
886	=item L<AnyEvent::BDB>
887
888	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
889	L<BDB> and AnyEvent together.
890
891	=item L<AnyEvent::GPSD>
892
893	A non-blocking interface to gpsd, a daemon delivering GPS information.
894
895	=item L<AnyEvent::IGS>
896
897	A non-blocking interface to the Internet Go Server protocol (used by
898	L<App::IGS>).
899
900	=item L<AnyEvent::IRC>
901
902	AnyEvent based IRC client module family (replacing the older Net::IRC3).
903
904	=item L<Net::XMPP2>
905
906	AnyEvent based XMPP (Jabber protocol) module family.
907
908	=item L<Net::FCP>
909
910	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
911	of AnyEvent.
912
913	=item L<Event::ExecFlow>
914
915	High level API for event-based execution flow control.
916
917	=item L<Coro>	1150	=item L<Coro>
918		1151
919	Has special support for AnyEvent via L<Coro::AnyEvent>.	1152	Has special support for AnyEvent via L<Coro::AnyEvent>.
920		1153
921	=item L<IO::Lambda>
922
923	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
924
925	=back	1154	=back
926		1155
927	=cut	1156	=cut
928		1157
929	package AnyEvent;	1158	package AnyEvent;
930		1159
931	no warnings;	1160	# basically a tuned-down version of common::sense
932	use strict qw(vars subs);	1161	sub common_sense {
		1162	# from common:.sense 1.0
		1163	${^WARNING_BITS} = "\xfc\x3f\x33\x00\x0f\xf3\xcf\xc0\xf3\xfc\x33\x00";
		1164	# use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)
		1165	$^H |= 0x00000600;
		1166	}
933		1167
		1168	BEGIN { AnyEvent::common_sense }
		1169
934	use Carp;	1170	use Carp ();
935		1171
936	our $VERSION = 4.411;	1172	our $VERSION = '5.271';
937	our $MODEL;	1173	our $MODEL;
938		1174
939	our $AUTOLOAD;	1175	our $AUTOLOAD;
940	our @ISA;	1176	our @ISA;
941		1177
942	our @REGISTRY;	1178	our @REGISTRY;
943		1179
944	our $WIN32;	1180	our $VERBOSE;
945		1181
946	BEGIN {	1182	BEGIN {
947	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";	1183	require "AnyEvent/constants.pl";
		1184
948	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";	1185	eval "sub TAINT (){" . (${^TAINT}*1) . "}";
949		1186
950	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}	1187	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
951	if ${^TAINT};	1188	if ${^TAINT};
952	}
953		1189
954	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1190	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
		1191
		1192	}
		1193
		1194	our $MAX_SIGNAL_LATENCY = 10;
955		1195
956	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred	1196	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
957		1197
958	{	1198	{
959	my $idx;	1199	my $idx;
…		…
961	for reverse split /\s*,\s*/,	1201	for reverse split /\s*,\s*/,
962	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1202	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
963	}	1203	}
964		1204
965	my @models = (	1205	my @models = (
966	[EV:: => AnyEvent::Impl::EV::],	1206	[EV:: => AnyEvent::Impl::EV:: , 1],
967	[Event:: => AnyEvent::Impl::Event::],
968	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	1207	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],
969	# everything below here will not be autoprobed	1208	# everything below here will not (normally) be autoprobed
970	# as the pureperl backend should work everywhere	1209	# as the pureperl backend should work everywhere
971	# and is usually faster	1210	# and is usually faster
		1211	[Event:: => AnyEvent::Impl::Event::, 1],
		1212	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
		1213	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
		1214	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
972	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1215	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
973	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
974	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
975	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1216	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
976	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1217	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
977	[Wx:: => AnyEvent::Impl::POE::],	1218	[Wx:: => AnyEvent::Impl::POE::],
978	[Prima:: => AnyEvent::Impl::POE::],	1219	[Prima:: => AnyEvent::Impl::POE::],
		1220	# IO::Async is just too broken - we would need workarounds for its
		1221	# byzantine signal and broken child handling, among others.
		1222	# IO::Async is rather hard to detect, as it doesn't have any
		1223	# obvious default class.
		1224	[IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1225	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1226	[IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1227	[AnyEvent::Impl::IOAsync:: => AnyEvent::Impl::IOAsync::], # requires special main program
979	);	1228	);
980		1229
981	our %method = map +($_ => 1),	1230	our %method = map +($_ => 1),
982	qw(io timer time now now_update signal child idle condvar one_event DESTROY);	1231	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
983		1232
984	our @post_detect;	1233	our @post_detect;
985		1234
986	sub post_detect(&) {	1235	sub post_detect(&) {
987	my ($cb) = @_;	1236	my ($cb) = @_;
988		1237
989	if ($MODEL) {
990	$cb->();
991
992	1
993	} else {
994	push @post_detect, $cb;	1238	push @post_detect, $cb;
995		1239
996	defined wantarray	1240	defined wantarray
997	? bless \$cb, "AnyEvent::Util::postdetect"	1241	? bless \$cb, "AnyEvent::Util::postdetect"
998	: ()	1242	: ()
999	}
1000	}	1243	}
1001		1244
1002	sub AnyEvent::Util::postdetect::DESTROY {	1245	sub AnyEvent::Util::postdetect::DESTROY {
1003	@post_detect = grep $_ != ${$_[0]}, @post_detect;	1246	@post_detect = grep $_ != ${$_[0]}, @post_detect;
1004	}	1247	}
1005		1248
1006	sub detect() {	1249	sub detect() {
		1250	# free some memory
		1251	*detect = sub () { $MODEL };
		1252
		1253	local $!; # for good measure
		1254	local $SIG{__DIE__};
		1255
		1256	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
		1257	my $model = "AnyEvent::Impl::$1";
		1258	if (eval "require $model") {
		1259	$MODEL = $model;
		1260	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
		1261	} else {
		1262	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
		1263	}
		1264	}
		1265
		1266	# check for already loaded models
1007	unless ($MODEL) {	1267	unless ($MODEL) {
1008	no strict 'refs';	1268	for (@REGISTRY, @models) {
1009	local $SIG{__DIE__};	1269	my ($package, $model) = @$_;
1010		1270	if (${"$package\::VERSION"} > 0) {
1011	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
1012	my $model = "AnyEvent::Impl::$1";
1013	if (eval "require $model") {	1271	if (eval "require $model") {
1014	$MODEL = $model;	1272	$MODEL = $model;
1015	warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1;	1273	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1016	} else {	1274	last;
1017	warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose;	1275	}
1018	}	1276	}
1019	}	1277	}
1020		1278
1021	# check for already loaded models
1022	unless ($MODEL) {	1279	unless ($MODEL) {
		1280	# try to autoload a model
1023	for (@REGISTRY, @models) {	1281	for (@REGISTRY, @models) {
1024	my ($package, $model) = @$_;	1282	my ($package, $model, $autoload) = @$_;
		1283	if (
		1284	$autoload
		1285	and eval "require $package"
1025	if (${"$package\::VERSION"} > 0) {	1286	and ${"$package\::VERSION"} > 0
1026	if (eval "require $model") {	1287	and eval "require $model"
		1288	) {
1027	$MODEL = $model;	1289	$MODEL = $model;
1028	warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1;	1290	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
1029	last;	1291	last;
1030	}
1031	}	1292	}
1032	}	1293	}
1033		1294
1034	unless ($MODEL) {
1035	# try to load a model
1036
1037	for (@REGISTRY, @models) {
1038	my ($package, $model) = @$_;
1039	if (eval "require $package"
1040	and ${"$package\::VERSION"} > 0
1041	and eval "require $model") {
1042	$MODEL = $model;
1043	warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1;
1044	last;
1045	}
1046	}
1047
1048	$MODEL	1295	$MODEL
1049	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";	1296	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
1050	}
1051	}	1297	}
1052
1053	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1054
1055	unshift @ISA, $MODEL;
1056
1057	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
1058
1059	(shift @post_detect)->() while @post_detect;
1060	}	1298	}
		1299
		1300	@models = (); # free probe data
		1301
		1302	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1303	unshift @ISA, $MODEL;
		1304
		1305	# now nuke some methods that are overriden by the backend.
		1306	# SUPER is not allowed.
		1307	for (qw(time signal child idle)) {
		1308	undef &{"AnyEvent::Base::$_"}
		1309	if defined &{"$MODEL\::$_"};
		1310	}
		1311
		1312	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
		1313
		1314	(shift @post_detect)->() while @post_detect;
		1315
		1316	*post_detect = sub(&) {
		1317	shift->();
		1318
		1319	undef
		1320	};
1061		1321
1062	$MODEL	1322	$MODEL
1063	}	1323	}
1064		1324
1065	sub AUTOLOAD {	1325	sub AUTOLOAD {
1066	(my $func = $AUTOLOAD) =~ s/.*://;	1326	(my $func = $AUTOLOAD) =~ s/.*://;
1067		1327
1068	$method{$func}	1328	$method{$func}
1069	or croak "$func: not a valid method for AnyEvent objects";	1329	or Carp::croak "$func: not a valid AnyEvent class method";
1070		1330
1071	detect unless $MODEL;	1331	detect;
1072		1332
1073	my $class = shift;	1333	my $class = shift;
1074	$class->$func (@_);	1334	$class->$func (@_);
1075	}	1335	}
1076		1336
1077	# utility function to dup a filehandle. this is used by many backends	1337	# utility function to dup a filehandle. this is used by many backends
1078	# to support binding more than one watcher per filehandle (they usually	1338	# to support binding more than one watcher per filehandle (they usually
1079	# allow only one watcher per fd, so we dup it to get a different one).	1339	# allow only one watcher per fd, so we dup it to get a different one).
1080	sub _dupfh($$$$) {	1340	sub _dupfh($$;$$) {
1081	my ($poll, $fh, $r, $w) = @_;	1341	my ($poll, $fh, $r, $w) = @_;
1082		1342
1083	# cygwin requires the fh mode to be matching, unix doesn't	1343	# cygwin requires the fh mode to be matching, unix doesn't
1084	my ($rw, $mode) = $poll eq "r" ? ($r, "<")	1344	my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1085	: $poll eq "w" ? ($w, ">")
1086	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1087		1345
1088	open my $fh2, "$mode&" . fileno $fh	1346	open my $fh2, $mode, $fh
1089	or die "cannot dup() filehandle: $!,";	1347	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1090		1348
1091	# we assume CLOEXEC is already set by perl in all important cases	1349	# we assume CLOEXEC is already set by perl in all important cases
1092		1350
1093	($fh2, $rw)	1351	($fh2, $rw)
1094	}	1352	}
1095		1353
		1354	=head1 SIMPLIFIED AE API
		1355
		1356	Starting with version 5.0, AnyEvent officially supports a second, much
		1357	simpler, API that is designed to reduce the calling, typing and memory
		1358	overhead by using function call syntax and a fixed number of parameters.
		1359
		1360	See the L<AE> manpage for details.
		1361
		1362	=cut
		1363
		1364	package AE;
		1365
		1366	our $VERSION = $AnyEvent::VERSION;
		1367
		1368	# fall back to the main API by default - backends and AnyEvent::Base
		1369	# implementations can overwrite these.
		1370
		1371	sub io($$$) {
		1372	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
		1373	}
		1374
		1375	sub timer($$$) {
		1376	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
		1377	}
		1378
		1379	sub signal($$) {
		1380	AnyEvent->signal (signal => $_[0], cb => $_[1])
		1381	}
		1382
		1383	sub child($$) {
		1384	AnyEvent->child (pid => $_[0], cb => $_[1])
		1385	}
		1386
		1387	sub idle($) {
		1388	AnyEvent->idle (cb => $_[0])
		1389	}
		1390
		1391	sub cv(;&) {
		1392	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
		1393	}
		1394
		1395	sub now() {
		1396	AnyEvent->now
		1397	}
		1398
		1399	sub now_update() {
		1400	AnyEvent->now_update
		1401	}
		1402
		1403	sub time() {
		1404	AnyEvent->time
		1405	}
		1406
1096	package AnyEvent::Base;	1407	package AnyEvent::Base;
1097		1408
1098	# default implementations for many methods	1409	# default implementations for many methods
1099		1410
1100	BEGIN {	1411	sub time {
		1412	eval q{ # poor man's autoloading {}
		1413	# probe for availability of Time::HiRes
1101	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {	1414	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1415	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1102	*_time = \&Time::HiRes::time;	1416	*AE::time = \&Time::HiRes::time;
1103	# if (eval "use POSIX (); (POSIX::times())...	1417	# if (eval "use POSIX (); (POSIX::times())...
1104	} else {	1418	} else {
		1419	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1105	*_time = sub { time }; # epic fail	1420	*AE::time = sub (){ time }; # epic fail
		1421	}
		1422
		1423	*time = sub { AE::time }; # different prototypes
		1424	};
		1425	die if $@;
		1426
		1427	&time
		1428	}
		1429
		1430	*now = \&time;
		1431
		1432	sub now_update { }
		1433
		1434	# default implementation for ->condvar
		1435
		1436	sub condvar {
		1437	eval q{ # poor man's autoloading {}
		1438	*condvar = sub {
		1439	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
		1440	};
		1441
		1442	*AE::cv = sub (;&) {
		1443	bless { @_ ? (_ae_cb => shift) : () }, "AnyEvent::CondVar"
		1444	};
		1445	};
		1446	die if $@;
		1447
		1448	&condvar
		1449	}
		1450
		1451	# default implementation for ->signal
		1452
		1453	our $HAVE_ASYNC_INTERRUPT;
		1454
		1455	sub _have_async_interrupt() {
		1456	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
		1457	&& eval "use Async::Interrupt 1.02 (); 1")
		1458	unless defined $HAVE_ASYNC_INTERRUPT;
		1459
		1460	$HAVE_ASYNC_INTERRUPT
		1461	}
		1462
		1463	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1464	our (%SIG_ASY, %SIG_ASY_W);
		1465	our ($SIG_COUNT, $SIG_TW);
		1466
		1467	# install a dummy wakeup watcher to reduce signal catching latency
		1468	# used by Impls
		1469	sub _sig_add() {
		1470	unless ($SIG_COUNT++) {
		1471	# try to align timer on a full-second boundary, if possible
		1472	my $NOW = AE::now;
		1473
		1474	$SIG_TW = AE::timer
		1475	$MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
		1476	$MAX_SIGNAL_LATENCY,
		1477	sub { } # just for the PERL_ASYNC_CHECK
		1478	;
1106	}	1479	}
1107	}	1480	}
1108		1481
1109	sub time { _time }	1482	sub _sig_del {
1110	sub now { _time }	1483	undef $SIG_TW
1111	sub now_update { }	1484	unless --$SIG_COUNT;
1112
1113	# default implementation for ->condvar
1114
1115	sub condvar {
1116	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1117	}	1485	}
1118		1486
1119	# default implementation for ->signal	1487	our $_sig_name_init; $_sig_name_init = sub {
		1488	eval q{ # poor man's autoloading {}
		1489	undef $_sig_name_init;
1120		1490
1121	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1491	if (_have_async_interrupt) {
		1492	*sig2num = \&Async::Interrupt::sig2num;
		1493	*sig2name = \&Async::Interrupt::sig2name;
		1494	} else {
		1495	require Config;
1122		1496
1123	sub _signal_exec {	1497	my %signame2num;
1124	sysread $SIGPIPE_R, my $dummy, 4;	1498	@signame2num{ split ' ', $Config::Config{sig_name} }
		1499	= split ' ', $Config::Config{sig_num};
1125		1500
1126	while (%SIG_EV) {	1501	my @signum2name;
1127	for (keys %SIG_EV) {	1502	@signum2name[values %signame2num] = keys %signame2num;
1128	delete $SIG_EV{$_};	1503
1129	$_->() for values %{ $SIG_CB{$_} || {} };	1504	*sig2num = sub($) {
		1505	$_[0] > 0 ? shift : $signame2num{+shift}
		1506	};
		1507	*sig2name = sub ($) {
		1508	$_[0] > 0 ? $signum2name[+shift] : shift
		1509	};
1130	}	1510	}
1131	}	1511	};
1132	}	1512	die if $@;
		1513	};
		1514
		1515	sub sig2num ($) { &$_sig_name_init; &sig2num }
		1516	sub sig2name($) { &$_sig_name_init; &sig2name }
1133		1517
1134	sub signal {	1518	sub signal {
1135	my (undef, %arg) = @_;	1519	eval q{ # poor man's autoloading {}
		1520	# probe for availability of Async::Interrupt
		1521	if (_have_async_interrupt) {
		1522	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1136		1523
1137	unless ($SIGPIPE_R) {	1524	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1138	require Fcntl;	1525	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1139		1526
1140	if (AnyEvent::WIN32) {
1141	require AnyEvent::Util;
1142
1143	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1144	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1145	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1146	} else {	1527	} else {
		1528	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
		1529
		1530	if (AnyEvent::WIN32) {
		1531	require AnyEvent::Util;
		1532
		1533	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1534	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
		1535	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
		1536	} else {
1147	pipe $SIGPIPE_R, $SIGPIPE_W;	1537	pipe $SIGPIPE_R, $SIGPIPE_W;
1148	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;	1538	fcntl $SIGPIPE_R, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_R;
1149	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case	1539	fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case
1150		1540
1151	# not strictly required, as $^F is normally 2, but let's make sure...	1541	# not strictly required, as $^F is normally 2, but let's make sure...
1152	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1542	fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
1153	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1543	fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
		1544	}
		1545
		1546	$SIGPIPE_R
		1547	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1548
		1549	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
1154	}	1550	}
1155		1551
1156	$SIGPIPE_R	1552	*signal = $HAVE_ASYNC_INTERRUPT
1157	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";	1553	? sub {
		1554	my (undef, %arg) = @_;
1158		1555
1159	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);	1556	# async::interrupt
1160	}
1161
1162	my $signal = uc $arg{signal}	1557	my $signal = sig2num $arg{signal};
1163	or Carp::croak "required option 'signal' is missing";
1164
1165	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1558	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1559
		1560	$SIG_ASY{$signal} ||= new Async::Interrupt
		1561	cb => sub { undef $SIG_EV{$signal} },
		1562	signal => $signal,
		1563	pipe => [$SIGPIPE_R->filenos],
		1564	pipe_autodrain => 0,
		1565	;
		1566
		1567	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1568	}
		1569	: sub {
		1570	my (undef, %arg) = @_;
		1571
		1572	# pure perl
		1573	my $signal = sig2name $arg{signal};
		1574	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1575
1166	$SIG{$signal} ||= sub {	1576	$SIG{$signal} ||= sub {
1167	local $!;	1577	local $!;
1168	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;	1578	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1169	undef $SIG_EV{$signal};	1579	undef $SIG_EV{$signal};
		1580	};
		1581
		1582	# can't do signal processing without introducing races in pure perl,
		1583	# so limit the signal latency.
		1584	_sig_add;
		1585
		1586	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1587	}
		1588	;
		1589
		1590	*AnyEvent::Base::signal::DESTROY = sub {
		1591	my ($signal, $cb) = @{$_[0]};
		1592
		1593	_sig_del;
		1594
		1595	delete $SIG_CB{$signal}{$cb};
		1596
		1597	$HAVE_ASYNC_INTERRUPT
		1598	? delete $SIG_ASY{$signal}
		1599	: # delete doesn't work with older perls - they then
		1600	# print weird messages, or just unconditionally exit
		1601	# instead of getting the default action.
		1602	undef $SIG{$signal}
		1603	unless keys %{ $SIG_CB{$signal} };
		1604	};
		1605
		1606	*_signal_exec = sub {
		1607	$HAVE_ASYNC_INTERRUPT
		1608	? $SIGPIPE_R->drain
		1609	: sysread $SIGPIPE_R, (my $dummy), 9;
		1610
		1611	while (%SIG_EV) {
		1612	for (keys %SIG_EV) {
		1613	delete $SIG_EV{$_};
		1614	$_->() for values %{ $SIG_CB{$_} || {} };
		1615	}
		1616	}
		1617	};
1170	};	1618	};
		1619	die if $@;
1171		1620
1172	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"	1621	&signal
1173	}
1174
1175	sub AnyEvent::Base::signal::DESTROY {
1176	my ($signal, $cb) = @{$_[0]};
1177
1178	delete $SIG_CB{$signal}{$cb};
1179
1180	# delete doesn't work with older perls - they then
1181	# print weird messages, or just unconditionally exit
1182	# instead of getting the default action.
1183	undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
1184	}	1622	}
1185		1623
1186	# default implementation for ->child	1624	# default implementation for ->child
1187		1625
1188	our %PID_CB;	1626	our %PID_CB;
1189	our $CHLD_W;	1627	our $CHLD_W;
1190	our $CHLD_DELAY_W;	1628	our $CHLD_DELAY_W;
1191	our $WNOHANG;	1629	our $WNOHANG;
1192		1630
1193	sub _sigchld {	1631	# used by many Impl's
1194	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1632	sub _emit_childstatus($$) {
		1633	my (undef, $rpid, $rstatus) = @_;
		1634
		1635	$_->($rpid, $rstatus)
1195	$_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),	1636	for values %{ $PID_CB{$rpid} || {} },
1196	(values %{ $PID_CB{0} || {} });	1637	values %{ $PID_CB{0} || {} };
1197	}
1198	}	1638	}
1199		1639
1200	sub child {	1640	sub child {
		1641	eval q{ # poor man's autoloading {}
		1642	*_sigchld = sub {
		1643	my $pid;
		1644
		1645	AnyEvent->_emit_childstatus ($pid, $?)
		1646	while ($pid = waitpid -1, $WNOHANG) > 0;
		1647	};
		1648
		1649	*child = sub {
1201	my (undef, %arg) = @_;	1650	my (undef, %arg) = @_;
1202		1651
1203	defined (my $pid = $arg{pid} + 0)	1652	defined (my $pid = $arg{pid} + 0)
1204	or Carp::croak "required option 'pid' is missing";	1653	or Carp::croak "required option 'pid' is missing";
1205		1654
1206	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1655	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1207		1656
		1657	# WNOHANG is almost cetrainly 1 everywhere
		1658	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
		1659	? 1
1208	$WNOHANG ||= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;	1660	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1209		1661
1210	unless ($CHLD_W) {	1662	unless ($CHLD_W) {
1211	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1663	$CHLD_W = AE::signal CHLD => \&_sigchld;
1212	# child could be a zombie already, so make at least one round	1664	# child could be a zombie already, so make at least one round
1213	&_sigchld;	1665	&_sigchld;
1214	}	1666	}
1215		1667
1216	bless [$pid, $arg{cb}], "AnyEvent::Base::child"	1668	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1217	}	1669	};
1218		1670
1219	sub AnyEvent::Base::child::DESTROY {	1671	*AnyEvent::Base::child::DESTROY = sub {
1220	my ($pid, $cb) = @{$_[0]};	1672	my ($pid, $cb) = @{$_[0]};
1221		1673
1222	delete $PID_CB{$pid}{$cb};	1674	delete $PID_CB{$pid}{$cb};
1223	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1675	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1224		1676
1225	undef $CHLD_W unless keys %PID_CB;	1677	undef $CHLD_W unless keys %PID_CB;
		1678	};
		1679	};
		1680	die if $@;
		1681
		1682	&child
1226	}	1683	}
1227		1684
1228	# idle emulation is done by simply using a timer, regardless	1685	# idle emulation is done by simply using a timer, regardless
1229	# of whether the process is idle or not, and not letting	1686	# of whether the process is idle or not, and not letting
1230	# the callback use more than 50% of the time.	1687	# the callback use more than 50% of the time.
1231	sub idle {	1688	sub idle {
		1689	eval q{ # poor man's autoloading {}
		1690	*idle = sub {
1232	my (undef, %arg) = @_;	1691	my (undef, %arg) = @_;
1233		1692
1234	my ($cb, $w, $rcb) = $arg{cb};	1693	my ($cb, $w, $rcb) = $arg{cb};
1235		1694
1236	$rcb = sub {	1695	$rcb = sub {
1237	if ($cb) {	1696	if ($cb) {
1238	$w = _time;	1697	$w = _time;
1239	&$cb;	1698	&$cb;
1240	$w = _time - $w;	1699	$w = _time - $w;
1241		1700
1242	# never use more then 50% of the time for the idle watcher,	1701	# never use more then 50% of the time for the idle watcher,
1243	# within some limits	1702	# within some limits
1244	$w = 0.0001 if $w < 0.0001;	1703	$w = 0.0001 if $w < 0.0001;
1245	$w = 5 if $w > 5;	1704	$w = 5 if $w > 5;
1246		1705
1247	$w = AnyEvent->timer (after => $w, cb => $rcb);	1706	$w = AE::timer $w, 0, $rcb;
1248	} else {	1707	} else {
1249	# clean up...	1708	# clean up...
1250	undef $w;	1709	undef $w;
1251	undef $rcb;	1710	undef $rcb;
		1711	}
		1712	};
		1713
		1714	$w = AE::timer 0.05, 0, $rcb;
		1715
		1716	bless \\$cb, "AnyEvent::Base::idle"
1252	}	1717	};
		1718
		1719	*AnyEvent::Base::idle::DESTROY = sub {
		1720	undef $${$_[0]};
		1721	};
1253	};	1722	};
		1723	die if $@;
1254		1724
1255	$w = AnyEvent->timer (after => 0.05, cb => $rcb);	1725	&idle
1256
1257	bless \\$cb, "AnyEvent::Base::idle"
1258	}
1259
1260	sub AnyEvent::Base::idle::DESTROY {
1261	undef $${$_[0]};
1262	}	1726	}
1263		1727
1264	package AnyEvent::CondVar;	1728	package AnyEvent::CondVar;
1265		1729
1266	our @ISA = AnyEvent::CondVar::Base::;	1730	our @ISA = AnyEvent::CondVar::Base::;
1267		1731
1268	package AnyEvent::CondVar::Base;	1732	package AnyEvent::CondVar::Base;
1269		1733
1270	use overload	1734	#use overload
1271	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1735	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1272	fallback => 1;	1736	# fallback => 1;
		1737
		1738	# save 300+ kilobytes by dirtily hardcoding overloading
		1739	${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
		1740	*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
		1741	*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
		1742	${'AnyEvent::CondVar::Base::()'} = 1; # fallback
		1743
		1744	our $WAITING;
1273		1745
1274	sub _send {	1746	sub _send {
1275	# nop	1747	# nop
1276	}	1748	}
1277		1749
…		…
1290	sub ready {	1762	sub ready {
1291	$_[0]{_ae_sent}	1763	$_[0]{_ae_sent}
1292	}	1764	}
1293		1765
1294	sub _wait {	1766	sub _wait {
		1767	$WAITING
		1768	and !$_[0]{_ae_sent}
		1769	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
		1770
		1771	local $WAITING = 1;
1295	AnyEvent->one_event while !$_[0]{_ae_sent};	1772	AnyEvent->one_event while !$_[0]{_ae_sent};
1296	}	1773	}
1297		1774
1298	sub recv {	1775	sub recv {
1299	$_[0]->_wait;	1776	$_[0]->_wait;
…		…
1301	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1778	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
1302	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1779	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
1303	}	1780	}
1304		1781
1305	sub cb {	1782	sub cb {
1306	$_[0]{_ae_cb} = $_[1] if @_ > 1;	1783	my $cv = shift;
		1784
		1785	@_
		1786	and $cv->{_ae_cb} = shift
		1787	and $cv->{_ae_sent}
		1788	and (delete $cv->{_ae_cb})->($cv);
		1789
1307	$_[0]{_ae_cb}	1790	$cv->{_ae_cb}
1308	}	1791	}
1309		1792
1310	sub begin {	1793	sub begin {
1311	++$_[0]{_ae_counter};	1794	++$_[0]{_ae_counter};
1312	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;	1795	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
…		…
1361	C<PERL_ANYEVENT_MODEL>.	1844	C<PERL_ANYEVENT_MODEL>.
1362		1845
1363	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	1846	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1364	model it chooses.	1847	model it chooses.
1365		1848
		1849	When set to C<8> or higher, then AnyEvent will report extra information on
		1850	which optional modules it loads and how it implements certain features.
		1851
1366	=item C<PERL_ANYEVENT_STRICT>	1852	=item C<PERL_ANYEVENT_STRICT>
1367		1853
1368	AnyEvent does not do much argument checking by default, as thorough	1854	AnyEvent does not do much argument checking by default, as thorough
1369	argument checking is very costly. Setting this variable to a true value	1855	argument checking is very costly. Setting this variable to a true value
1370	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly	1856	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1371	check the arguments passed to most method calls. If it finds any problems	1857	check the arguments passed to most method calls. If it finds any problems,
1372	it will croak.	1858	it will croak.
1373		1859
1374	In other words, enables "strict" mode.	1860	In other words, enables "strict" mode.
1375		1861
1376	Unlike C<use strict>, it is definitely recommended ot keep it off in	1862	Unlike C<use strict> (or its modern cousin, C<< use L<common::sense>
1377	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while	1863	>>, it is definitely recommended to keep it off in production. Keeping
1378	developing programs can be very useful, however.	1864	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
		1865	can be very useful, however.
1379		1866
1380	=item C<PERL_ANYEVENT_MODEL>	1867	=item C<PERL_ANYEVENT_MODEL>
1381		1868
1382	This can be used to specify the event model to be used by AnyEvent, before	1869	This can be used to specify the event model to be used by AnyEvent, before
1383	auto detection and -probing kicks in. It must be a string consisting	1870	auto detection and -probing kicks in. It must be a string consisting
…		…
1426		1913
1427	=item C<PERL_ANYEVENT_MAX_FORKS>	1914	=item C<PERL_ANYEVENT_MAX_FORKS>
1428		1915
1429	The maximum number of child processes that C<AnyEvent::Util::fork_call>	1916	The maximum number of child processes that C<AnyEvent::Util::fork_call>
1430	will create in parallel.	1917	will create in parallel.
		1918
		1919	=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
		1920
		1921	The default value for the C<max_outstanding> parameter for the default DNS
		1922	resolver - this is the maximum number of parallel DNS requests that are
		1923	sent to the DNS server.
		1924
		1925	=item C<PERL_ANYEVENT_RESOLV_CONF>
		1926
		1927	The file to use instead of F</etc/resolv.conf> (or OS-specific
		1928	configuration) in the default resolver. When set to the empty string, no
		1929	default config will be used.
		1930
		1931	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
		1932
		1933	When neither C<ca_file> nor C<ca_path> was specified during
		1934	L<AnyEvent::TLS> context creation, and either of these environment
		1935	variables exist, they will be used to specify CA certificate locations
		1936	instead of a system-dependent default.
		1937
		1938	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
		1939
		1940	When these are set to C<1>, then the respective modules are not
		1941	loaded. Mostly good for testing AnyEvent itself.
1431		1942
1432	=back	1943	=back
1433		1944
1434	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1945	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1435		1946
…		…
1493	warn "read: $input\n"; # output what has been read	2004	warn "read: $input\n"; # output what has been read
1494	$cv->send if $input =~ /^q/i; # quit program if /^q/i	2005	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1495	},	2006	},
1496	);	2007	);
1497		2008
1498	my $time_watcher; # can only be used once
1499
1500	sub new_timer {
1501	$timer = AnyEvent->timer (after => 1, cb => sub {	2009	my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1502	warn "timeout\n"; # print 'timeout' about every second	2010	warn "timeout\n"; # print 'timeout' at most every second
1503	&new_timer; # and restart the time
1504	});	2011	});
1505	}
1506
1507	new_timer; # create first timer
1508		2012
1509	$cv->recv; # wait until user enters /^q/i	2013	$cv->recv; # wait until user enters /^q/i
1510		2014
1511	=head1 REAL-WORLD EXAMPLE	2015	=head1 REAL-WORLD EXAMPLE
1512		2016
…		…
1585		2089
1586	The actual code goes further and collects all errors (C<die>s, exceptions)	2090	The actual code goes further and collects all errors (C<die>s, exceptions)
1587	that occurred during request processing. The C<result> method detects	2091	that occurred during request processing. The C<result> method detects
1588	whether an exception as thrown (it is stored inside the $txn object)	2092	whether an exception as thrown (it is stored inside the $txn object)
1589	and just throws the exception, which means connection errors and other	2093	and just throws the exception, which means connection errors and other
1590	problems get reported tot he code that tries to use the result, not in a	2094	problems get reported to the code that tries to use the result, not in a
1591	random callback.	2095	random callback.
1592		2096
1593	All of this enables the following usage styles:	2097	All of this enables the following usage styles:
1594		2098
1595	1. Blocking:	2099	1. Blocking:
…		…
1643	through AnyEvent. The benchmark creates a lot of timers (with a zero	2147	through AnyEvent. The benchmark creates a lot of timers (with a zero
1644	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	2148	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1645	which it is), lets them fire exactly once and destroys them again.	2149	which it is), lets them fire exactly once and destroys them again.
1646		2150
1647	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	2151	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1648	distribution.	2152	distribution. It uses the L<AE> interface, which makes a real difference
		2153	for the EV and Perl backends only.
1649		2154
1650	=head3 Explanation of the columns	2155	=head3 Explanation of the columns
1651		2156
1652	I<watcher> is the number of event watchers created/destroyed. Since	2157	I<watcher> is the number of event watchers created/destroyed. Since
1653	different event models feature vastly different performances, each event	2158	different event models feature vastly different performances, each event
…		…
1674	watcher.	2179	watcher.
1675		2180
1676	=head3 Results	2181	=head3 Results
1677		2182
1678	name watchers bytes create invoke destroy comment	2183	name watchers bytes create invoke destroy comment
1679	EV/EV 400000 224 0.47 0.35 0.27 EV native interface	2184	EV/EV 100000 223 0.47 0.43 0.27 EV native interface
1680	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	2185	EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
1681	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal	2186	Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
1682	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation	2187	Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
1683	Event/Event 16000 517 32.20 31.80 0.81 Event native interface	2188	Event/Event 16000 516 31.16 31.84 0.82 Event native interface
1684	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers	2189	Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
		2190	IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
		2191	IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
1685	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour	2192	Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
1686	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers	2193	Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
1687	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event	2194	POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
1688	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select	2195	POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
1689		2196
1690	=head3 Discussion	2197	=head3 Discussion
1691		2198
1692	The benchmark does I<not> measure scalability of the event loop very	2199	The benchmark does I<not> measure scalability of the event loop very
1693	well. For example, a select-based event loop (such as the pure perl one)	2200	well. For example, a select-based event loop (such as the pure perl one)
…		…
1705	benchmark machine, handling an event takes roughly 1600 CPU cycles with	2212	benchmark machine, handling an event takes roughly 1600 CPU cycles with
1706	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU	2213	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
1707	cycles with POE.	2214	cycles with POE.
1708		2215
1709	C<EV> is the sole leader regarding speed and memory use, which are both	2216	C<EV> is the sole leader regarding speed and memory use, which are both
1710	maximal/minimal, respectively. Even when going through AnyEvent, it uses	2217	maximal/minimal, respectively. When using the L<AE> API there is zero
		2218	overhead (when going through the AnyEvent API create is about 5-6 times
		2219	slower, with other times being equal, so still uses far less memory than
1711	far less memory than any other event loop and is still faster than Event	2220	any other event loop and is still faster than Event natively).
1712	natively.
1713		2221
1714	The pure perl implementation is hit in a few sweet spots (both the	2222	The pure perl implementation is hit in a few sweet spots (both the
1715	constant timeout and the use of a single fd hit optimisations in the perl	2223	constant timeout and the use of a single fd hit optimisations in the perl
1716	interpreter and the backend itself). Nevertheless this shows that it	2224	interpreter and the backend itself). Nevertheless this shows that it
1717	adds very little overhead in itself. Like any select-based backend its	2225	adds very little overhead in itself. Like any select-based backend its
1718	performance becomes really bad with lots of file descriptors (and few of	2226	performance becomes really bad with lots of file descriptors (and few of
1719	them active), of course, but this was not subject of this benchmark.	2227	them active), of course, but this was not subject of this benchmark.
1720		2228
1721	The C<Event> module has a relatively high setup and callback invocation	2229	The C<Event> module has a relatively high setup and callback invocation
1722	cost, but overall scores in on the third place.	2230	cost, but overall scores in on the third place.
		2231
		2232	C<IO::Async> performs admirably well, about on par with C<Event>, even
		2233	when using its pure perl backend.
1723		2234
1724	C<Glib>'s memory usage is quite a bit higher, but it features a	2235	C<Glib>'s memory usage is quite a bit higher, but it features a
1725	faster callback invocation and overall ends up in the same class as	2236	faster callback invocation and overall ends up in the same class as
1726	C<Event>. However, Glib scales extremely badly, doubling the number of	2237	C<Event>. However, Glib scales extremely badly, doubling the number of
1727	watchers increases the processing time by more than a factor of four,	2238	watchers increases the processing time by more than a factor of four,
…		…
1788	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100	2299	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1789	(1%) are active. This mirrors the activity of large servers with many	2300	(1%) are active. This mirrors the activity of large servers with many
1790	connections, most of which are idle at any one point in time.	2301	connections, most of which are idle at any one point in time.
1791		2302
1792	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	2303	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1793	distribution.	2304	distribution. It uses the L<AE> interface, which makes a real difference
		2305	for the EV and Perl backends only.
1794		2306
1795	=head3 Explanation of the columns	2307	=head3 Explanation of the columns
1796		2308
1797	I<sockets> is the number of sockets, and twice the number of "servers" (as	2309	I<sockets> is the number of sockets, and twice the number of "servers" (as
1798	each server has a read and write socket end).	2310	each server has a read and write socket end).
…		…
1805	it to another server. This includes deleting the old timeout and creating	2317	it to another server. This includes deleting the old timeout and creating
1806	a new one that moves the timeout into the future.	2318	a new one that moves the timeout into the future.
1807		2319
1808	=head3 Results	2320	=head3 Results
1809		2321
1810	name sockets create request	2322	name sockets create request
1811	EV 20000 69.01 11.16	2323	EV 20000 62.66 7.99
1812	Perl 20000 73.32 35.87	2324	Perl 20000 68.32 32.64
1813	Event 20000 212.62 257.32	2325	IOAsync 20000 174.06 101.15 epoll
1814	Glib 20000 651.16 1896.30	2326	IOAsync 20000 174.67 610.84 poll
		2327	Event 20000 202.69 242.91
		2328	Glib 20000 557.01 1689.52
1815	POE 20000 349.67 12317.24 uses POE::Loop::Event	2329	POE 20000 341.54 12086.32 uses POE::Loop::Event
1816		2330
1817	=head3 Discussion	2331	=head3 Discussion
1818		2332
1819	This benchmark I<does> measure scalability and overall performance of the	2333	This benchmark I<does> measure scalability and overall performance of the
1820	particular event loop.	2334	particular event loop.
…		…
1822	EV is again fastest. Since it is using epoll on my system, the setup time	2336	EV is again fastest. Since it is using epoll on my system, the setup time
1823	is relatively high, though.	2337	is relatively high, though.
1824		2338
1825	Perl surprisingly comes second. It is much faster than the C-based event	2339	Perl surprisingly comes second. It is much faster than the C-based event
1826	loops Event and Glib.	2340	loops Event and Glib.
		2341
		2342	IO::Async performs very well when using its epoll backend, and still quite
		2343	good compared to Glib when using its pure perl backend.
1827		2344
1828	Event suffers from high setup time as well (look at its code and you will	2345	Event suffers from high setup time as well (look at its code and you will
1829	understand why). Callback invocation also has a high overhead compared to	2346	understand why). Callback invocation also has a high overhead compared to
1830	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event	2347	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
1831	uses select or poll in basically all documented configurations.	2348	uses select or poll in basically all documented configurations.
…		…
1900		2417
1901	Recently I was told about the benchmark in the IO::Lambda manpage, which	2418	Recently I was told about the benchmark in the IO::Lambda manpage, which
1902	could be misinterpreted to make AnyEvent look bad. In fact, the benchmark	2419	could be misinterpreted to make AnyEvent look bad. In fact, the benchmark
1903	simply compares IO::Lambda with POE, and IO::Lambda looks better (which	2420	simply compares IO::Lambda with POE, and IO::Lambda looks better (which
1904	shouldn't come as a surprise to anybody). As such, the benchmark is	2421	shouldn't come as a surprise to anybody). As such, the benchmark is
1905	fine, and shows that the AnyEvent backend from IO::Lambda isn't very	2422	fine, and mostly shows that the AnyEvent backend from IO::Lambda isn't
1906	optimal. But how would AnyEvent compare when used without the extra	2423	very optimal. But how would AnyEvent compare when used without the extra
1907	baggage? To explore this, I wrote the equivalent benchmark for AnyEvent.	2424	baggage? To explore this, I wrote the equivalent benchmark for AnyEvent.
1908		2425
1909	The benchmark itself creates an echo-server, and then, for 500 times,	2426	The benchmark itself creates an echo-server, and then, for 500 times,
1910	connects to the echo server, sends a line, waits for the reply, and then	2427	connects to the echo server, sends a line, waits for the reply, and then
1911	creates the next connection. This is a rather bad benchmark, as it doesn't	2428	creates the next connection. This is a rather bad benchmark, as it doesn't
1912	test the efficiency of the framework, but it is a benchmark nevertheless.	2429	test the efficiency of the framework or much non-blocking I/O, but it is a
		2430	benchmark nevertheless.
1913		2431
1914	name runtime	2432	name runtime
1915	Lambda/select 0.330 sec	2433	Lambda/select 0.330 sec
1916	+ optimized 0.122 sec	2434	+ optimized 0.122 sec
1917	Lambda/AnyEvent 0.327 sec	2435	Lambda/AnyEvent 0.327 sec
…		…
1923		2441
1924	AnyEvent/select/nb 0.085 sec	2442	AnyEvent/select/nb 0.085 sec
1925	AnyEvent/EV/nb 0.068 sec	2443	AnyEvent/EV/nb 0.068 sec
1926	+state machine 0.134 sec	2444	+state machine 0.134 sec
1927		2445
1928	The benchmark is also a bit unfair (my fault) - the IO::Lambda	2446	The benchmark is also a bit unfair (my fault): the IO::Lambda/POE
1929	benchmarks actually make blocking connects and use 100% blocking I/O,	2447	benchmarks actually make blocking connects and use 100% blocking I/O,
1930	defeating the purpose of an event-based solution. All of the newly	2448	defeating the purpose of an event-based solution. All of the newly
1931	written AnyEvent benchmarks use 100% non-blocking connects (using	2449	written AnyEvent benchmarks use 100% non-blocking connects (using
1932	AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS	2450	AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS
1933	resolver), so AnyEvent is at a disadvantage here as non-blocking connects	2451	resolver), so AnyEvent is at a disadvantage here, as non-blocking connects
1934	generally require a lot more bookkeeping and event handling than blocking	2452	generally require a lot more bookkeeping and event handling than blocking
1935	connects (which involve a single syscall only).	2453	connects (which involve a single syscall only).
1936		2454
1937	The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which	2455	The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which
1938	offers similar expressive power as POE and IO::Lambda (using conventional	2456	offers similar expressive power as POE and IO::Lambda, using conventional
1939	Perl syntax), which means both the echo server and the client are 100%	2457	Perl syntax. This means that both the echo server and the client are 100%
1940	non-blocking w.r.t. I/O, further placing it at a disadvantage.	2458	non-blocking, further placing it at a disadvantage.
1941		2459
1942	As you can see, AnyEvent + EV even beats the hand-optimised "raw sockets	2460	As you can see, the AnyEvent + EV combination even beats the
1943	benchmark", while AnyEvent + its pure perl backend easily beats	2461	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
1944	IO::Lambda and POE.	2462	backend easily beats IO::Lambda and POE.
1945		2463
1946	And even the 100% non-blocking version written using the high-level (and	2464	And even the 100% non-blocking version written using the high-level (and
1947	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda,	2465	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
		2466	higher level ("unoptimised") abstractions by a large margin, even though
1948	even thought it does all of DNS, tcp-connect and socket I/O in a	2467	it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
1949	non-blocking way.	2468
		2469	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
		2470	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
		2471	part of the IO::Lambda distribution and were used without any changes.
1950		2472
1951		2473
1952	=head1 SIGNALS	2474	=head1 SIGNALS
1953		2475
1954	AnyEvent currently installs handlers for these signals:	2476	AnyEvent currently installs handlers for these signals:
…		…
1958	=item SIGCHLD	2480	=item SIGCHLD
1959		2481
1960	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher	2482	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
1961	emulation for event loops that do not support them natively. Also, some	2483	emulation for event loops that do not support them natively. Also, some
1962	event loops install a similar handler.	2484	event loops install a similar handler.
		2485
		2486	Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
		2487	AnyEvent will reset it to default, to avoid losing child exit statuses.
1963		2488
1964	=item SIGPIPE	2489	=item SIGPIPE
1965		2490
1966	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>	2491	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
1967	when AnyEvent gets loaded.	2492	when AnyEvent gets loaded.
…		…
1979		2504
1980	=back	2505	=back
1981		2506
1982	=cut	2507	=cut
1983		2508
		2509	undef $SIG{CHLD}
		2510	if $SIG{CHLD} eq 'IGNORE';
		2511
1984	$SIG{PIPE} = sub { }	2512	$SIG{PIPE} = sub { }
1985	unless defined $SIG{PIPE};	2513	unless defined $SIG{PIPE};
1986		2514
		2515	=head1 RECOMMENDED/OPTIONAL MODULES
		2516
		2517	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
		2518	its built-in modules) are required to use it.
		2519
		2520	That does not mean that AnyEvent won't take advantage of some additional
		2521	modules if they are installed.
		2522
		2523	This section explains which additional modules will be used, and how they
		2524	affect AnyEvent's operation.
		2525
		2526	=over 4
		2527
		2528	=item L<Async::Interrupt>
		2529
		2530	This slightly arcane module is used to implement fast signal handling: To
		2531	my knowledge, there is no way to do completely race-free and quick
		2532	signal handling in pure perl. To ensure that signals still get
		2533	delivered, AnyEvent will start an interval timer to wake up perl (and
		2534	catch the signals) with some delay (default is 10 seconds, look for
		2535	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
		2536
		2537	If this module is available, then it will be used to implement signal
		2538	catching, which means that signals will not be delayed, and the event loop
		2539	will not be interrupted regularly, which is more efficient (and good for
		2540	battery life on laptops).
		2541
		2542	This affects not just the pure-perl event loop, but also other event loops
		2543	that have no signal handling on their own (e.g. Glib, Tk, Qt).
		2544
		2545	Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
		2546	and either employ their own workarounds (POE) or use AnyEvent's workaround
		2547	(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
		2548	does nothing for those backends.
		2549
		2550	=item L<EV>
		2551
		2552	This module isn't really "optional", as it is simply one of the backend
		2553	event loops that AnyEvent can use. However, it is simply the best event
		2554	loop available in terms of features, speed and stability: It supports
		2555	the AnyEvent API optimally, implements all the watcher types in XS, does
		2556	automatic timer adjustments even when no monotonic clock is available,
		2557	can take avdantage of advanced kernel interfaces such as C<epoll> and
		2558	C<kqueue>, and is the fastest backend I<by far>. You can even embed
		2559	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
		2560
		2561	If you only use backends that rely on another event loop (e.g. C<Tk>),
		2562	then this module will do nothing for you.
		2563
		2564	=item L<Guard>
		2565
		2566	The guard module, when used, will be used to implement
		2567	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
		2568	lot less memory), but otherwise doesn't affect guard operation much. It is
		2569	purely used for performance.
		2570
		2571	=item L<JSON> and L<JSON::XS>
		2572
		2573	One of these modules is required when you want to read or write JSON data
		2574	via L<AnyEvent::Handle>. L<JSON> is also written in pure-perl, but can take
		2575	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
		2576
		2577	=item L<Net::SSLeay>
		2578
		2579	Implementing TLS/SSL in Perl is certainly interesting, but not very
		2580	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
		2581	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
		2582
		2583	=item L<Time::HiRes>
		2584
		2585	This module is part of perl since release 5.008. It will be used when the
		2586	chosen event library does not come with a timing source of its own. The
		2587	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
		2588	try to use a monotonic clock for timing stability.
		2589
		2590	=back
		2591
1987		2592
1988	=head1 FORK	2593	=head1 FORK
1989		2594
1990	Most event libraries are not fork-safe. The ones who are usually are	2595	Most event libraries are not fork-safe. The ones who are usually are
1991	because they rely on inefficient but fork-safe C<select> or C<poll>	2596	because they rely on inefficient but fork-safe C<select> or C<poll> calls
1992	calls. Only L<EV> is fully fork-aware.	2597	- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
		2598	are usually badly thought-out hacks that are incompatible with fork in
		2599	one way or another. Only L<EV> is fully fork-aware and ensures that you
		2600	continue event-processing in both parent and child (or both, if you know
		2601	what you are doing).
		2602
		2603	This means that, in general, you cannot fork and do event processing in
		2604	the child if the event library was initialised before the fork (which
		2605	usually happens when the first AnyEvent watcher is created, or the library
		2606	is loaded).
1993		2607
1994	If you have to fork, you must either do so I<before> creating your first	2608	If you have to fork, you must either do so I<before> creating your first
1995	watcher OR you must not use AnyEvent at all in the child.	2609	watcher OR you must not use AnyEvent at all in the child OR you must do
		2610	something completely out of the scope of AnyEvent.
		2611
		2612	The problem of doing event processing in the parent I<and> the child
		2613	is much more complicated: even for backends that I<are> fork-aware or
		2614	fork-safe, their behaviour is not usually what you want: fork clones all
		2615	watchers, that means all timers, I/O watchers etc. are active in both
		2616	parent and child, which is almost never what you want. USing C<exec>
		2617	to start worker children from some kind of manage rprocess is usually
		2618	preferred, because it is much easier and cleaner, at the expense of having
		2619	to have another binary.
1996		2620
1997		2621
1998	=head1 SECURITY CONSIDERATIONS	2622	=head1 SECURITY CONSIDERATIONS
1999		2623
2000	AnyEvent can be forced to load any event model via	2624	AnyEvent can be forced to load any event model via
…		…
2014	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	2638	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
2015	be used to probe what backend is used and gain other information (which is	2639	be used to probe what backend is used and gain other information (which is
2016	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and	2640	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
2017	$ENV{PERL_ANYEVENT_STRICT}.	2641	$ENV{PERL_ANYEVENT_STRICT}.
2018		2642
		2643	Note that AnyEvent will remove I<all> environment variables starting with
		2644	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		2645	enabled.
		2646
2019		2647
2020	=head1 BUGS	2648	=head1 BUGS
2021		2649
2022	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard	2650	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
2023	to work around. If you suffer from memleaks, first upgrade to Perl 5.10	2651	to work around. If you suffer from memleaks, first upgrade to Perl 5.10
…		…
2034	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2662	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
2035		2663
2036	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2664	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
2037	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2665	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
2038	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2666	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
2039	L<AnyEvent::Impl::POE>.	2667	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.
2040		2668
2041	Non-blocking file handles, sockets, TCP clients and	2669	Non-blocking file handles, sockets, TCP clients and
2042	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.	2670	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2043		2671
2044	Asynchronous DNS: L<AnyEvent::DNS>.	2672	Asynchronous DNS: L<AnyEvent::DNS>.
2045		2673
2046	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,	2674	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,
		2675	L<Coro::Event>,
2047		2676
2048	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.	2677	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,
		2678	L<AnyEvent::HTTP>.
2049		2679
2050		2680
2051	=head1 AUTHOR	2681	=head1 AUTHOR
2052		2682
2053	Marc Lehmann <schmorp@schmorp.de>	2683	Marc Lehmann <schmorp@schmorp.de>

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