[ViewVC] Diff of: cvs/AnyEvent/lib/AnyEvent.pm

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.143 by root, Wed May 28 23:57:38 2008 UTC vs.
Revision 1.194 by root, Sun Mar 22 03:56:37 2009 UTC

…		…
1	=head1 => NAME	1	=head1 NAME
2		2
3	AnyEvent - provide framework for multiple event loops	3	AnyEvent - provide framework for multiple event loops
4		4
5	EV, Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event loops	5	EV, Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event loops
6		6
7	=head1 SYNOPSIS	7	=head1 SYNOPSIS
8		8
9	use AnyEvent;	9	use AnyEvent;
10		10
11	my $w = AnyEvent->io (fh => $fh, poll => "r\|w", cb => sub {	11	my $w = AnyEvent->io (fh => $fh, poll => "r\|w", cb => sub { ... });
12	...
13	});
14		12
15	my $w = AnyEvent->timer (after => $seconds, cb => sub {	13	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
		14	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...
		15
		16	print AnyEvent->now; # prints current event loop time
		17	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
		18
		19	my $w = AnyEvent->signal (signal => "TERM", cb => sub { ... });
		20
		21	my $w = AnyEvent->child (pid => $pid, cb => sub {
		22	my ($pid, $status) = @_;
16	...	23	...
17	});	24	});
18		25
19	my $w = AnyEvent->condvar; # stores whether a condition was flagged	26	my $w = AnyEvent->condvar; # stores whether a condition was flagged
20	$w->send; # wake up current and all future recv's	27	$w->send; # wake up current and all future recv's
21	$w->recv; # enters "main loop" till $condvar gets ->send	28	$w->recv; # enters "main loop" till $condvar gets ->send
		29	# use a condvar in callback mode:
		30	$w->cb (sub { $_[0]->recv });
		31
		32	=head1 INTRODUCTION/TUTORIAL
		33
		34	This manpage is mainly a reference manual. If you are interested
		35	in a tutorial or some gentle introduction, have a look at the
		36	L<AnyEvent::Intro> manpage.
22		37
23	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)	38	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
24		39
25	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen	40	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
26	nowadays. So what is different about AnyEvent?	41	nowadays. So what is different about AnyEvent?
27		42
28	Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of	43	Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of
29	policy> and AnyEvent is I<small and efficient>.	44	policy> and AnyEvent is I<small and efficient>.
30		45
31	First and foremost, I<AnyEvent is not an event model> itself, it only	46	First and foremost, I<AnyEvent is not an event model> itself, it only
32	interfaces to whatever event model the main program happens to use in a	47	interfaces to whatever event model the main program happens to use, in a
33	pragmatic way. For event models and certain classes of immortals alike,	48	pragmatic way. For event models and certain classes of immortals alike,
34	the statement "there can only be one" is a bitter reality: In general,	49	the statement "there can only be one" is a bitter reality: In general,
35	only one event loop can be active at the same time in a process. AnyEvent	50	only one event loop can be active at the same time in a process. AnyEvent
36	helps hiding the differences between those event loops.	51	cannot change this, but it can hide the differences between those event
		52	loops.
37		53
38	The goal of AnyEvent is to offer module authors the ability to do event	54	The goal of AnyEvent is to offer module authors the ability to do event
39	programming (waiting for I/O or timer events) without subscribing to a	55	programming (waiting for I/O or timer events) without subscribing to a
40	religion, a way of living, and most importantly: without forcing your	56	religion, a way of living, and most importantly: without forcing your
41	module users into the same thing by forcing them to use the same event	57	module users into the same thing by forcing them to use the same event
42	model you use.	58	model you use.
43		59
44	For modules like POE or IO::Async (which is a total misnomer as it is	60	For modules like POE or IO::Async (which is a total misnomer as it is
45	actually doing all I/O I<synchronously>...), using them in your module is	61	actually doing all I/O I<synchronously>...), using them in your module is
46	like joining a cult: After you joined, you are dependent on them and you	62	like joining a cult: After you joined, you are dependent on them and you
47	cannot use anything else, as it is simply incompatible to everything that	63	cannot use anything else, as they are simply incompatible to everything
48	isn't itself. What's worse, all the potential users of your module are	64	that isn't them. What's worse, all the potential users of your
49	I<also> forced to use the same event loop you use.	65	module are I<also> forced to use the same event loop you use.
50		66
51	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works	67	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
52	fine. AnyEvent + Tk works fine etc. etc. but none of these work together	68	fine. AnyEvent + Tk works fine etc. etc. but none of these work together
53	with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if	69	with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if
54	your module uses one of those, every user of your module has to use it,	70	your module uses one of those, every user of your module has to use it,
55	too. But if your module uses AnyEvent, it works transparently with all	71	too. But if your module uses AnyEvent, it works transparently with all
56	event models it supports (including stuff like POE and IO::Async, as long	72	event models it supports (including stuff like IO::Async, as long as those
57	as those use one of the supported event loops. It is trivial to add new	73	use one of the supported event loops. It is trivial to add new event loops
58	event loops to AnyEvent, too, so it is future-proof).	74	to AnyEvent, too, so it is future-proof).
59		75
60	In addition to being free of having to use I<the one and only true event	76	In addition to being free of having to use I<the one and only true event
61	model>, AnyEvent also is free of bloat and policy: with POE or similar	77	model>, AnyEvent also is free of bloat and policy: with POE or similar
62	modules, you get an enormous amount of code and strict rules you have to	78	modules, you get an enormous amount of code and strict rules you have to
63	follow. AnyEvent, on the other hand, is lean and up to the point, by only	79	follow. AnyEvent, on the other hand, is lean and up to the point, by only
132	Many watchers either are used with "recursion" (repeating timers for	148	Many watchers either are used with "recursion" (repeating timers for
133	example), or need to refer to their watcher object in other ways.	149	example), or need to refer to their watcher object in other ways.
134		150
135	An any way to achieve that is this pattern:	151	An any way to achieve that is this pattern:
136		152
137	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {	153	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
138	# you can use $w here, for example to undef it	154	# you can use $w here, for example to undef it
139	undef $w;	155	undef $w;
140	});	156	});
141		157
142	Note that C<my $w; $w => combination. This is necessary because in Perl,	158	Note that C<my $w; $w => combination. This is necessary because in Perl,
143	my variables are only visible after the statement in which they are	159	my variables are only visible after the statement in which they are
144	declared.	160	declared.
145		161
146	=head2 I/O WATCHERS	162	=head2 I/O WATCHERS
147		163
148	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	164	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
149	with the following mandatory key-value pairs as arguments:	165	with the following mandatory key-value pairs as arguments:
150		166
151	C<fh> the Perl I<file handle> (I<not> file descriptor) to watch	167	C<fh> the Perl I<file handle> (I<not> file descriptor) to watch for events
152	for events. C<poll> must be a string that is either C<r> or C<w>,	168	(AnyEvent might or might not keep a reference to this file handle). C<poll>
153	which creates a watcher waiting for "r"eadable or "w"ritable events,	169	must be a string that is either C<r> or C<w>, which creates a watcher
154	respectively. C<cb> is the callback to invoke each time the file handle	170	waiting for "r"eadable or "w"ritable events, respectively. C<cb> is the
155	becomes ready.	171	callback to invoke each time the file handle becomes ready.
156		172
157	Although the callback might get passed parameters, their value and	173	Although the callback might get passed parameters, their value and
158	presence is undefined and you cannot rely on them. Portable AnyEvent	174	presence is undefined and you cannot rely on them. Portable AnyEvent
159	callbacks cannot use arguments passed to I/O watcher callbacks.	175	callbacks cannot use arguments passed to I/O watcher callbacks.
160		176
…		…
164		180
165	Some event loops issue spurious readyness notifications, so you should	181	Some event loops issue spurious readyness notifications, so you should
166	always use non-blocking calls when reading/writing from/to your file	182	always use non-blocking calls when reading/writing from/to your file
167	handles.	183	handles.
168		184
169	Example:
170
171	# wait for readability of STDIN, then read a line and disable the watcher	185	Example: wait for readability of STDIN, then read a line and disable the
		186	watcher.
		187
172	my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {	188	my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
173	chomp (my $input = <STDIN>);	189	chomp (my $input = <STDIN>);
174	warn "read: $input\n";	190	warn "read: $input\n";
175	undef $w;	191	undef $w;
176	});	192	});
…		…
186		202
187	Although the callback might get passed parameters, their value and	203	Although the callback might get passed parameters, their value and
188	presence is undefined and you cannot rely on them. Portable AnyEvent	204	presence is undefined and you cannot rely on them. Portable AnyEvent
189	callbacks cannot use arguments passed to time watcher callbacks.	205	callbacks cannot use arguments passed to time watcher callbacks.
190		206
191	The timer callback will be invoked at most once: if you want a repeating	207	The callback will normally be invoked once only. If you specify another
192	timer you have to create a new watcher (this is a limitation by both Tk	208	parameter, C<interval>, as a strictly positive number (> 0), then the
193	and Glib).	209	callback will be invoked regularly at that interval (in fractional
		210	seconds) after the first invocation. If C<interval> is specified with a
		211	false value, then it is treated as if it were missing.
194		212
195	Example:	213	The callback will be rescheduled before invoking the callback, but no
		214	attempt is done to avoid timer drift in most backends, so the interval is
		215	only approximate.
196		216
197	# fire an event after 7.7 seconds	217	Example: fire an event after 7.7 seconds.
		218
198	my $w = AnyEvent->timer (after => 7.7, cb => sub {	219	my $w = AnyEvent->timer (after => 7.7, cb => sub {
199	warn "timeout\n";	220	warn "timeout\n";
200	});	221	});
201		222
202	# to cancel the timer:	223	# to cancel the timer:
203	undef $w;	224	undef $w;
204		225
205	Example 2:
206
207	# fire an event after 0.5 seconds, then roughly every second	226	Example 2: fire an event after 0.5 seconds, then roughly every second.
208	my $w;
209		227
210	my $cb = sub {
211	# cancel the old timer while creating a new one
212	$w = AnyEvent->timer (after => 1, cb => $cb);	228	my $w = AnyEvent->timer (after => 0.5, interval => 1, cb => sub {
		229	warn "timeout\n";
213	};	230	};
214
215	# start the "loop" by creating the first watcher
216	$w = AnyEvent->timer (after => 0.5, cb => $cb);
217		231
218	=head3 TIMING ISSUES	232	=head3 TIMING ISSUES
219		233
220	There are two ways to handle timers: based on real time (relative, "fire	234	There are two ways to handle timers: based on real time (relative, "fire
221	in 10 seconds") and based on wallclock time (absolute, "fire at 12	235	in 10 seconds") and based on wallclock time (absolute, "fire at 12
…		…
243		257
244	This returns the "current wallclock time" as a fractional number of	258	This returns the "current wallclock time" as a fractional number of
245	seconds since the Epoch (the same thing as C<time> or C<Time::HiRes::time>	259	seconds since the Epoch (the same thing as C<time> or C<Time::HiRes::time>
246	return, and the result is guaranteed to be compatible with those).	260	return, and the result is guaranteed to be compatible with those).
247		261
248	It progresses independently of any event loop processing.	262	It progresses independently of any event loop processing, i.e. each call
249		263	will check the system clock, which usually gets updated frequently.
250	In almost all cases (in all cases if you don't care), this is the function
251	to call when you want to know the current time.
252		264
253	=item AnyEvent->now	265	=item AnyEvent->now
254		266
255	This also returns the "current wallclock time", but unlike C<time>, above,	267	This also returns the "current wallclock time", but unlike C<time>, above,
256	this value might change only once per event loop iteration, depending on	268	this value might change only once per event loop iteration, depending on
257	the event loop (most return the same time as C<time>, above). This is the	269	the event loop (most return the same time as C<time>, above). This is the
258	time that AnyEvent timers get scheduled against.	270	time that AnyEvent's timers get scheduled against.
		271
		272	I<In almost all cases (in all cases if you don't care), this is the
		273	function to call when you want to know the current time.>
		274
		275	This function is also often faster then C<< AnyEvent->time >>, and
		276	thus the preferred method if you want some timestamp (for example,
		277	L<AnyEvent::Handle> uses this to update it's activity timeouts).
		278
		279	The rest of this section is only of relevance if you try to be very exact
		280	with your timing, you can skip it without bad conscience.
259		281
260	For a practical example of when these times differ, consider L<Event::Lib>	282	For a practical example of when these times differ, consider L<Event::Lib>
261	and L<EV> and the following set-up:	283	and L<EV> and the following set-up:
262		284
263	The event loop is running and has just invoked one of your callback at	285	The event loop is running and has just invoked one of your callback at
…		…
268		290
269	With L<Event::Lib>, C<< AnyEvent->time >> and C<< AnyEvent->now >> will	291	With L<Event::Lib>, C<< AnyEvent->time >> and C<< AnyEvent->now >> will
270	both return C<501>, because that is the current time, and the timer will	292	both return C<501>, because that is the current time, and the timer will
271	be scheduled to fire at time=504 (C<501> + C<3>).	293	be scheduled to fire at time=504 (C<501> + C<3>).
272		294
273	With L<EV>m C<< AnyEvent->time >> returns C<501> (as that is the current	295	With L<EV>, C<< AnyEvent->time >> returns C<501> (as that is the current
274	time), but C<< AnyEvent->now >> returns C<500>, as that is the time the	296	time), but C<< AnyEvent->now >> returns C<500>, as that is the time the
275	last event processing phase started. With L<EV>, your timer gets scheduled	297	last event processing phase started. With L<EV>, your timer gets scheduled
276	to run at time=503 (C<500> + C<3>).	298	to run at time=503 (C<500> + C<3>).
277		299
278	In one sense, L<Event::Lib> is more exact, as it uses the current time	300	In one sense, L<Event::Lib> is more exact, as it uses the current time
279	regardless of any delays introduced by event processing. However, most	301	regardless of any delays introduced by event processing. However, most
280	callbacks do not expect large delays in processing, so this causes a	302	callbacks do not expect large delays in processing, so this causes a
281	higher drift (and a lot more syscalls to get the current time).	303	higher drift (and a lot more system calls to get the current time).
282		304
283	In another sense, L<EV> is more exact, as your timer will be scheduled at	305	In another sense, L<EV> is more exact, as your timer will be scheduled at
284	the same time, regardless of how long event processing actually took.	306	the same time, regardless of how long event processing actually took.
285		307
286	In either case, if you care (and in most cases, you don't), then you	308	In either case, if you care (and in most cases, you don't), then you
…		…
291	=back	313	=back
292		314
293	=head2 SIGNAL WATCHERS	315	=head2 SIGNAL WATCHERS
294		316
295	You can watch for signals using a signal watcher, C<signal> is the signal	317	You can watch for signals using a signal watcher, C<signal> is the signal
296	I<name> without any C<SIG> prefix, C<cb> is the Perl callback to	318	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
297	be invoked whenever a signal occurs.	319	callback to be invoked whenever a signal occurs.
298		320
299	Although the callback might get passed parameters, their value and	321	Although the callback might get passed parameters, their value and
300	presence is undefined and you cannot rely on them. Portable AnyEvent	322	presence is undefined and you cannot rely on them. Portable AnyEvent
301	callbacks cannot use arguments passed to signal watcher callbacks.	323	callbacks cannot use arguments passed to signal watcher callbacks.
302		324
…		…
318	=head2 CHILD PROCESS WATCHERS	340	=head2 CHILD PROCESS WATCHERS
319		341
320	You can also watch on a child process exit and catch its exit status.	342	You can also watch on a child process exit and catch its exit status.
321		343
322	The child process is specified by the C<pid> argument (if set to C<0>, it	344	The child process is specified by the C<pid> argument (if set to C<0>, it
323	watches for any child process exit). The watcher will trigger as often	345	watches for any child process exit). The watcher will triggered only when
324	as status change for the child are received. This works by installing a	346	the child process has finished and an exit status is available, not on
325	signal handler for C<SIGCHLD>. The callback will be called with the pid	347	any trace events (stopped/continued).
326	and exit status (as returned by waitpid), so unlike other watcher types,	348
327	you I<can> rely on child watcher callback arguments.	349	The callback will be called with the pid and exit status (as returned by
		350	waitpid), so unlike other watcher types, you I<can> rely on child watcher
		351	callback arguments.
		352
		353	This watcher type works by installing a signal handler for C<SIGCHLD>,
		354	and since it cannot be shared, nothing else should use SIGCHLD or reap
		355	random child processes (waiting for specific child processes, e.g. inside
		356	C<system>, is just fine).
328		357
329	There is a slight catch to child watchers, however: you usually start them	358	There is a slight catch to child watchers, however: you usually start them
330	I<after> the child process was created, and this means the process could	359	I<after> the child process was created, and this means the process could
331	have exited already (and no SIGCHLD will be sent anymore).	360	have exited already (and no SIGCHLD will be sent anymore).
332		361
…		…
338	AnyEvent program, you I<have> to create at least one watcher before you	367	AnyEvent program, you I<have> to create at least one watcher before you
339	C<fork> the child (alternatively, you can call C<AnyEvent::detect>).	368	C<fork> the child (alternatively, you can call C<AnyEvent::detect>).
340		369
341	Example: fork a process and wait for it	370	Example: fork a process and wait for it
342		371
343	my $done = AnyEvent->condvar;	372	my $done = AnyEvent->condvar;
344		373
345	my $pid = fork or exit 5;	374	my $pid = fork or exit 5;
346		375
347	my $w = AnyEvent->child (	376	my $w = AnyEvent->child (
348	pid => $pid,	377	pid => $pid,
349	cb => sub {	378	cb => sub {
350	my ($pid, $status) = @_;	379	my ($pid, $status) = @_;
351	warn "pid $pid exited with status $status";	380	warn "pid $pid exited with status $status";
352	$done->send;	381	$done->send;
353	},	382	},
354	);	383	);
355		384
356	# do something else, then wait for process exit	385	# do something else, then wait for process exit
357	$done->recv;	386	$done->recv;
358		387
359	=head2 CONDITION VARIABLES	388	=head2 CONDITION VARIABLES
360		389
361	If you are familiar with some event loops you will know that all of them	390	If you are familiar with some event loops you will know that all of them
362	require you to run some blocking "loop", "run" or similar function that	391	require you to run some blocking "loop", "run" or similar function that
…		…
368	The instrument to do that is called a "condition variable", so called	397	The instrument to do that is called a "condition variable", so called
369	because they represent a condition that must become true.	398	because they represent a condition that must become true.
370		399
371	Condition variables can be created by calling the C<< AnyEvent->condvar	400	Condition variables can be created by calling the C<< AnyEvent->condvar
372	>> method, usually without arguments. The only argument pair allowed is	401	>> method, usually without arguments. The only argument pair allowed is
		402
373	C<cb>, which specifies a callback to be called when the condition variable	403	C<cb>, which specifies a callback to be called when the condition variable
374	becomes true.	404	becomes true, with the condition variable as the first argument (but not
		405	the results).
375		406
376	After creation, the condition variable is "false" until it becomes "true"	407	After creation, the condition variable is "false" until it becomes "true"
377	by calling the C<send> method (or calling the condition variable as if it	408	by calling the C<send> method (or calling the condition variable as if it
378	were a callback, read about the caveats in the description for the C<<	409	were a callback, read about the caveats in the description for the C<<
379	->send >> method).	410	->send >> method).
…		…
435		466
436	my $done = AnyEvent->condvar;	467	my $done = AnyEvent->condvar;
437	my $delay = AnyEvent->timer (after => 5, cb => $done);	468	my $delay = AnyEvent->timer (after => 5, cb => $done);
438	$done->recv;	469	$done->recv;
439		470
		471	Example: Imagine an API that returns a condvar and doesn't support
		472	callbacks. This is how you make a synchronous call, for example from
		473	the main program:
		474
		475	use AnyEvent::CouchDB;
		476
		477	...
		478
		479	my @info = $couchdb->info->recv;
		480
		481	And this is how you would just ste a callback to be called whenever the
		482	results are available:
		483
		484	$couchdb->info->cb (sub {
		485	my @info = $_[0]->recv;
		486	});
		487
440	=head3 METHODS FOR PRODUCERS	488	=head3 METHODS FOR PRODUCERS
441		489
442	These methods should only be used by the producing side, i.e. the	490	These methods should only be used by the producing side, i.e. the
443	code/module that eventually sends the signal. Note that it is also	491	code/module that eventually sends the signal. Note that it is also
444	the producer side which creates the condvar in most cases, but it isn't	492	the producer side which creates the condvar in most cases, but it isn't
…		…
577	=item $bool = $cv->ready	625	=item $bool = $cv->ready
578		626
579	Returns true when the condition is "true", i.e. whether C<send> or	627	Returns true when the condition is "true", i.e. whether C<send> or
580	C<croak> have been called.	628	C<croak> have been called.
581		629
582	=item $cb = $cv->cb ([new callback])	630	=item $cb = $cv->cb ($cb->($cv))
583		631
584	This is a mutator function that returns the callback set and optionally	632	This is a mutator function that returns the callback set and optionally
585	replaces it before doing so.	633	replaces it before doing so.
586		634
587	The callback will be called when the condition becomes "true", i.e. when	635	The callback will be called when the condition becomes "true", i.e. when
588	C<send> or C<croak> are called. Calling C<recv> inside the callback	636	C<send> or C<croak> are called, with the only argument being the condition
589	or at any later time is guaranteed not to block.	637	variable itself. Calling C<recv> inside the callback or at any later time
		638	is guaranteed not to block.
590		639
591	=back	640	=back
592		641
593	=head1 GLOBAL VARIABLES AND FUNCTIONS	642	=head1 GLOBAL VARIABLES AND FUNCTIONS
594		643
…		…
723	=item L<AnyEvent::Util>	772	=item L<AnyEvent::Util>
724		773
725	Contains various utility functions that replace often-used but blocking	774	Contains various utility functions that replace often-used but blocking
726	functions such as C<inet_aton> by event-/callback-based versions.	775	functions such as C<inet_aton> by event-/callback-based versions.
727		776
728	=item L<AnyEvent::Handle>
729
730	Provide read and write buffers and manages watchers for reads and writes.
731
732	=item L<AnyEvent::Socket>	777	=item L<AnyEvent::Socket>
733		778
734	Provides various utility functions for (internet protocol) sockets,	779	Provides various utility functions for (internet protocol) sockets,
735	addresses and name resolution. Also functions to create non-blocking tcp	780	addresses and name resolution. Also functions to create non-blocking tcp
736	connections or tcp servers, with IPv6 and SRV record support and more.	781	connections or tcp servers, with IPv6 and SRV record support and more.
737		782
		783	=item L<AnyEvent::Handle>
		784
		785	Provide read and write buffers, manages watchers for reads and writes,
		786	supports raw and formatted I/O, I/O queued and fully transparent and
		787	non-blocking SSL/TLS.
		788
738	=item L<AnyEvent::DNS>	789	=item L<AnyEvent::DNS>
739		790
740	Provides rich asynchronous DNS resolver capabilities.	791	Provides rich asynchronous DNS resolver capabilities.
741		792
		793	=item L<AnyEvent::HTTP>
		794
		795	A simple-to-use HTTP library that is capable of making a lot of concurrent
		796	HTTP requests.
		797
742	=item L<AnyEvent::HTTPD>	798	=item L<AnyEvent::HTTPD>
743		799
744	Provides a simple web application server framework.	800	Provides a simple web application server framework.
745		801
746	=item L<AnyEvent::FastPing>	802	=item L<AnyEvent::FastPing>
747		803
748	The fastest ping in the west.	804	The fastest ping in the west.
749		805
		806	=item L<AnyEvent::DBI>
		807
		808	Executes L<DBI> requests asynchronously in a proxy process.
		809
		810	=item L<AnyEvent::AIO>
		811
		812	Truly asynchronous I/O, should be in the toolbox of every event
		813	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
		814	together.
		815
		816	=item L<AnyEvent::BDB>
		817
		818	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
		819	L<BDB> and AnyEvent together.
		820
		821	=item L<AnyEvent::GPSD>
		822
		823	A non-blocking interface to gpsd, a daemon delivering GPS information.
		824
		825	=item L<AnyEvent::IGS>
		826
		827	A non-blocking interface to the Internet Go Server protocol (used by
		828	L<App::IGS>).
		829
750	=item L<Net::IRC3>	830	=item L<AnyEvent::IRC>
751		831
752	AnyEvent based IRC client module family.	832	AnyEvent based IRC client module family (replacing the older Net::IRC3).
753		833
754	=item L<Net::XMPP2>	834	=item L<Net::XMPP2>
755		835
756	AnyEvent based XMPP (Jabber protocol) module family.	836	AnyEvent based XMPP (Jabber protocol) module family.
757		837
…		…
766		846
767	=item L<Coro>	847	=item L<Coro>
768		848
769	Has special support for AnyEvent via L<Coro::AnyEvent>.	849	Has special support for AnyEvent via L<Coro::AnyEvent>.
770		850
771	=item L<AnyEvent::AIO>, L<IO::AIO>
772
773	Truly asynchronous I/O, should be in the toolbox of every event
774	programmer. AnyEvent::AIO transparently fuses IO::AIO and AnyEvent
775	together.
776
777	=item L<AnyEvent::BDB>, L<BDB>
778
779	Truly asynchronous Berkeley DB access. AnyEvent::AIO transparently fuses
780	IO::AIO and AnyEvent together.
781
782	=item L<IO::Lambda>	851	=item L<IO::Lambda>
783		852
784	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.	853	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
785		854
786	=back	855	=back
…		…
788	=cut	857	=cut
789		858
790	package AnyEvent;	859	package AnyEvent;
791		860
792	no warnings;	861	no warnings;
793	use strict;	862	use strict qw(vars subs);
794		863
795	use Carp;	864	use Carp;
796		865
797	our $VERSION = '4.05';	866	our $VERSION = 4.34;
798	our $MODEL;	867	our $MODEL;
799		868
800	our $AUTOLOAD;	869	our $AUTOLOAD;
801	our @ISA;	870	our @ISA;
802		871
…		…
905	$MODEL	974	$MODEL
906	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";	975	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";
907	}	976	}
908	}	977	}
909		978
		979	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		980
910	unshift @ISA, $MODEL;	981	unshift @ISA, $MODEL;
911	push @{"$MODEL\::ISA"}, "AnyEvent::Base";	982
		983	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
912		984
913	(shift @post_detect)->() while @post_detect;	985	(shift @post_detect)->() while @post_detect;
914	}	986	}
915		987
916	$MODEL	988	$MODEL
…		…
926		998
927	my $class = shift;	999	my $class = shift;
928	$class->$func (@_);	1000	$class->$func (@_);
929	}	1001	}
930		1002
		1003	# utility function to dup a filehandle. this is used by many backends
		1004	# to support binding more than one watcher per filehandle (they usually
		1005	# allow only one watcher per fd, so we dup it to get a different one).
		1006	sub _dupfh($$$$) {
		1007	my ($poll, $fh, $r, $w) = @_;
		1008
		1009	require Fcntl;
		1010
		1011	# cygwin requires the fh mode to be matching, unix doesn't
		1012	my ($rw, $mode) = $poll eq "r" ? ($r, "<")
		1013	: $poll eq "w" ? ($w, ">")
		1014	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
		1015
		1016	open my $fh2, "$mode&" . fileno $fh
		1017	or die "cannot dup() filehandle: $!";
		1018
		1019	# we assume CLOEXEC is already set by perl in all important cases
		1020
		1021	($fh2, $rw)
		1022	}
		1023
931	package AnyEvent::Base;	1024	package AnyEvent::Base;
932		1025
933	# default implementation for now and time	1026	# default implementation for now and time
934		1027
935	use Time::HiRes ();	1028	BEGIN {
		1029	if (eval "use Time::HiRes (); time (); 1") {
		1030	*_time = \&Time::HiRes::time;
		1031	# if (eval "use POSIX (); (POSIX::times())...
		1032	} else {
		1033	*_time = sub { time }; # epic fail
		1034	}
		1035	}
936		1036
937	sub time { Time::HiRes::time }	1037	sub time { _time }
938	sub now { Time::HiRes::time }	1038	sub now { _time }
939		1039
940	# default implementation for ->condvar	1040	# default implementation for ->condvar
941		1041
942	sub condvar {	1042	sub condvar {
943	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::	1043	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::
…		…
964	sub AnyEvent::Base::Signal::DESTROY {	1064	sub AnyEvent::Base::Signal::DESTROY {
965	my ($signal, $cb) = @{$_[0]};	1065	my ($signal, $cb) = @{$_[0]};
966		1066
967	delete $SIG_CB{$signal}{$cb};	1067	delete $SIG_CB{$signal}{$cb};
968		1068
969	$SIG{$signal} = 'DEFAULT' unless keys %{ $SIG_CB{$signal} };	1069	delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
970	}	1070	}
971		1071
972	# default implementation for ->child	1072	# default implementation for ->child
973		1073
974	our %PID_CB;	1074	our %PID_CB;
…		…
1082		1182
1083	# undocumented/compatibility with pre-3.4	1183	# undocumented/compatibility with pre-3.4
1084	*broadcast = \&send;	1184	*broadcast = \&send;
1085	*wait = \&_wait;	1185	*wait = \&_wait;
1086		1186
		1187	=head1 ERROR AND EXCEPTION HANDLING
		1188
		1189	In general, AnyEvent does not do any error handling - it relies on the
		1190	caller to do that if required. The L<AnyEvent::Strict> module (see also
		1191	the C<PERL_ANYEVENT_STRICT> environment variable, below) provides strict
		1192	checking of all AnyEvent methods, however, which is highly useful during
		1193	development.
		1194
		1195	As for exception handling (i.e. runtime errors and exceptions thrown while
		1196	executing a callback), this is not only highly event-loop specific, but
		1197	also not in any way wrapped by this module, as this is the job of the main
		1198	program.
		1199
		1200	The pure perl event loop simply re-throws the exception (usually
		1201	within C<< condvar->recv >>), the L<Event> and L<EV> modules call C<<
		1202	$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and
		1203	so on.
		1204
		1205	=head1 ENVIRONMENT VARIABLES
		1206
		1207	The following environment variables are used by this module or its
		1208	submodules:
		1209
		1210	=over 4
		1211
		1212	=item C<PERL_ANYEVENT_VERBOSE>
		1213
		1214	By default, AnyEvent will be completely silent except in fatal
		1215	conditions. You can set this environment variable to make AnyEvent more
		1216	talkative.
		1217
		1218	When set to C<1> or higher, causes AnyEvent to warn about unexpected
		1219	conditions, such as not being able to load the event model specified by
		1220	C<PERL_ANYEVENT_MODEL>.
		1221
		1222	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
		1223	model it chooses.
		1224
		1225	=item C<PERL_ANYEVENT_STRICT>
		1226
		1227	AnyEvent does not do much argument checking by default, as thorough
		1228	argument checking is very costly. Setting this variable to a true value
		1229	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
		1230	check the arguments passed to most method calls. If it finds any problems
		1231	it will croak.
		1232
		1233	In other words, enables "strict" mode.
		1234
		1235	Unlike C<use strict>, it is definitely recommended ot keep it off in
		1236	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while
		1237	developing programs can be very useful, however.
		1238
		1239	=item C<PERL_ANYEVENT_MODEL>
		1240
		1241	This can be used to specify the event model to be used by AnyEvent, before
		1242	auto detection and -probing kicks in. It must be a string consisting
		1243	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
		1244	and the resulting module name is loaded and if the load was successful,
		1245	used as event model. If it fails to load AnyEvent will proceed with
		1246	auto detection and -probing.
		1247
		1248	This functionality might change in future versions.
		1249
		1250	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
		1251	could start your program like this:
		1252
		1253	PERL_ANYEVENT_MODEL=Perl perl ...
		1254
		1255	=item C<PERL_ANYEVENT_PROTOCOLS>
		1256
		1257	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
		1258	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
		1259	of auto probing).
		1260
		1261	Must be set to a comma-separated list of protocols or address families,
		1262	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
		1263	used, and preference will be given to protocols mentioned earlier in the
		1264	list.
		1265
		1266	This variable can effectively be used for denial-of-service attacks
		1267	against local programs (e.g. when setuid), although the impact is likely
		1268	small, as the program has to handle conenction and other failures anyways.
		1269
		1270	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
		1271	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
		1272	- only support IPv4, never try to resolve or contact IPv6
		1273	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
		1274	IPv6, but prefer IPv6 over IPv4.
		1275
		1276	=item C<PERL_ANYEVENT_EDNS0>
		1277
		1278	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
		1279	for DNS. This extension is generally useful to reduce DNS traffic, but
		1280	some (broken) firewalls drop such DNS packets, which is why it is off by
		1281	default.
		1282
		1283	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
		1284	EDNS0 in its DNS requests.
		1285
		1286	=item C<PERL_ANYEVENT_MAX_FORKS>
		1287
		1288	The maximum number of child processes that C<AnyEvent::Util::fork_call>
		1289	will create in parallel.
		1290
		1291	=back
		1292
1087	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1293	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1088		1294
1089	This is an advanced topic that you do not normally need to use AnyEvent in	1295	This is an advanced topic that you do not normally need to use AnyEvent in
1090	a module. This section is only of use to event loop authors who want to	1296	a module. This section is only of use to event loop authors who want to
1091	provide AnyEvent compatibility.	1297	provide AnyEvent compatibility.
…		…
1124		1330
1125	I<rxvt-unicode> also cheats a bit by not providing blocking access to	1331	I<rxvt-unicode> also cheats a bit by not providing blocking access to
1126	condition variables: code blocking while waiting for a condition will	1332	condition variables: code blocking while waiting for a condition will
1127	C<die>. This still works with most modules/usages, and blocking calls must	1333	C<die>. This still works with most modules/usages, and blocking calls must
1128	not be done in an interactive application, so it makes sense.	1334	not be done in an interactive application, so it makes sense.
1129
1130	=head1 ENVIRONMENT VARIABLES
1131
1132	The following environment variables are used by this module:
1133
1134	=over 4
1135
1136	=item C<PERL_ANYEVENT_VERBOSE>
1137
1138	By default, AnyEvent will be completely silent except in fatal
1139	conditions. You can set this environment variable to make AnyEvent more
1140	talkative.
1141
1142	When set to C<1> or higher, causes AnyEvent to warn about unexpected
1143	conditions, such as not being able to load the event model specified by
1144	C<PERL_ANYEVENT_MODEL>.
1145
1146	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1147	model it chooses.
1148
1149	=item C<PERL_ANYEVENT_MODEL>
1150
1151	This can be used to specify the event model to be used by AnyEvent, before
1152	auto detection and -probing kicks in. It must be a string consisting
1153	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
1154	and the resulting module name is loaded and if the load was successful,
1155	used as event model. If it fails to load AnyEvent will proceed with
1156	auto detection and -probing.
1157
1158	This functionality might change in future versions.
1159
1160	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
1161	could start your program like this:
1162
1163	PERL_ANYEVENT_MODEL=Perl perl ...
1164
1165	=item C<PERL_ANYEVENT_PROTOCOLS>
1166
1167	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
1168	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
1169	of auto probing).
1170
1171	Must be set to a comma-separated list of protocols or address families,
1172	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
1173	used, and preference will be given to protocols mentioned earlier in the
1174	list.
1175
1176	This variable can effectively be used for denial-of-service attacks
1177	against local programs (e.g. when setuid), although the impact is likely
1178	small, as the program has to handle connection errors already-
1179
1180	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
1181	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1182	- only support IPv4, never try to resolve or contact IPv6
1183	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1184	IPv6, but prefer IPv6 over IPv4.
1185
1186	=item C<PERL_ANYEVENT_EDNS0>
1187
1188	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
1189	for DNS. This extension is generally useful to reduce DNS traffic, but
1190	some (broken) firewalls drop such DNS packets, which is why it is off by
1191	default.
1192
1193	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1194	EDNS0 in its DNS requests.
1195
1196	=item C<PERL_ANYEVENT_MAX_FORKS>
1197
1198	The maximum number of child processes that C<AnyEvent::Util::fork_call>
1199	will create in parallel.
1200
1201	=back
1202		1335
1203	=head1 EXAMPLE PROGRAM	1336	=head1 EXAMPLE PROGRAM
1204		1337
1205	The following program uses an I/O watcher to read data from STDIN, a timer	1338	The following program uses an I/O watcher to read data from STDIN, a timer
1206	to display a message once per second, and a condition variable to quit the	1339	to display a message once per second, and a condition variable to quit the
…		…
1400	watcher.	1533	watcher.
1401		1534
1402	=head3 Results	1535	=head3 Results
1403		1536
1404	name watchers bytes create invoke destroy comment	1537	name watchers bytes create invoke destroy comment
1405	EV/EV 400000 244 0.56 0.46 0.31 EV native interface	1538	EV/EV 400000 224 0.47 0.35 0.27 EV native interface
1406	EV/Any 100000 244 2.50 0.46 0.29 EV + AnyEvent watchers	1539	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers
1407	CoroEV/Any 100000 244 2.49 0.44 0.29 coroutines + Coro::Signal	1540	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal
1408	Perl/Any 100000 513 4.92 0.87 1.12 pure perl implementation	1541	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation
1409	Event/Event 16000 516 31.88 31.30 0.85 Event native interface	1542	Event/Event 16000 517 32.20 31.80 0.81 Event native interface
1410	Event/Any 16000 590 35.75 31.42 1.08 Event + AnyEvent watchers	1543	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers
1411	Glib/Any 16000 1357 98.22 12.41 54.00 quadratic behaviour	1544	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour
1412	Tk/Any 2000 1860 26.97 67.98 14.00 SEGV with >> 2000 watchers	1545	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers
1413	POE/Event 2000 6644 108.64 736.02 14.73 via POE::Loop::Event	1546	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event
1414	POE/Select 2000 6343 94.13 809.12 565.96 via POE::Loop::Select	1547	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select
1415		1548
1416	=head3 Discussion	1549	=head3 Discussion
1417		1550
1418	The benchmark does I<not> measure scalability of the event loop very	1551	The benchmark does I<not> measure scalability of the event loop very
1419	well. For example, a select-based event loop (such as the pure perl one)	1552	well. For example, a select-based event loop (such as the pure perl one)
…		…
1621	watchers, as the management overhead dominates.	1754	watchers, as the management overhead dominates.
1622		1755
1623	=back	1756	=back
1624		1757
1625		1758
		1759	=head1 SIGNALS
		1760
		1761	AnyEvent currently installs handlers for these signals:
		1762
		1763	=over 4
		1764
		1765	=item SIGCHLD
		1766
		1767	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
		1768	emulation for event loops that do not support them natively. Also, some
		1769	event loops install a similar handler.
		1770
		1771	=item SIGPIPE
		1772
		1773	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
		1774	when AnyEvent gets loaded.
		1775
		1776	The rationale for this is that AnyEvent users usually do not really depend
		1777	on SIGPIPE delivery (which is purely an optimisation for shell use, or
		1778	badly-written programs), but C<SIGPIPE> can cause spurious and rare
		1779	program exits as a lot of people do not expect C<SIGPIPE> when writing to
		1780	some random socket.
		1781
		1782	The rationale for installing a no-op handler as opposed to ignoring it is
		1783	that this way, the handler will be restored to defaults on exec.
		1784
		1785	Feel free to install your own handler, or reset it to defaults.
		1786
		1787	=back
		1788
		1789	=cut
		1790
		1791	$SIG{PIPE} = sub { }
		1792	unless defined $SIG{PIPE};
		1793
		1794
1626	=head1 FORK	1795	=head1 FORK
1627		1796
1628	Most event libraries are not fork-safe. The ones who are usually are	1797	Most event libraries are not fork-safe. The ones who are usually are
1629	because they rely on inefficient but fork-safe C<select> or C<poll>	1798	because they rely on inefficient but fork-safe C<select> or C<poll>
1630	calls. Only L<EV> is fully fork-aware.	1799	calls. Only L<EV> is fully fork-aware.
…		…
1643	specified in the variable.	1812	specified in the variable.
1644		1813
1645	You can make AnyEvent completely ignore this variable by deleting it	1814	You can make AnyEvent completely ignore this variable by deleting it
1646	before the first watcher gets created, e.g. with a C<BEGIN> block:	1815	before the first watcher gets created, e.g. with a C<BEGIN> block:
1647		1816
1648	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }	1817	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }
1649		1818
1650	use AnyEvent;	1819	use AnyEvent;
1651		1820
1652	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	1821	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1653	be used to probe what backend is used and gain other information (which is	1822	be used to probe what backend is used and gain other information (which is
1654	probably even less useful to an attacker than PERL_ANYEVENT_MODEL).	1823	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
		1824	$ENV{PERL_ANYEGENT_STRICT}.
		1825
		1826
		1827	=head1 BUGS
		1828
		1829	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
		1830	to work around. If you suffer from memleaks, first upgrade to Perl 5.10
		1831	and check wether the leaks still show up. (Perl 5.10.0 has other annoying
		1832	mamleaks, such as leaking on C<map> and C<grep> but it is usually not as
		1833	pronounced).
1655		1834
1656		1835
1657	=head1 SEE ALSO	1836	=head1 SEE ALSO
1658		1837
1659	Utility functions: L<AnyEvent::Util>.	1838	Utility functions: L<AnyEvent::Util>.
…		…
1676	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.	1855	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.
1677		1856
1678		1857
1679	=head1 AUTHOR	1858	=head1 AUTHOR
1680		1859
1681	Marc Lehmann <schmorp@schmorp.de>	1860	Marc Lehmann <schmorp@schmorp.de>
1682	http://home.schmorp.de/	1861	http://home.schmorp.de/
1683		1862
1684	=cut	1863	=cut
1685		1864
1686	1	1865	1
1687		1866

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Comparing AnyEvent/lib/AnyEvent.pm (file contents): Revision 1.143 by root, Wed May 28 23:57:38 2008 UTC vs. Revision 1.194 by root, Sun Mar 22 03:56:37 2009 UTC

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Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.143 by root, Wed May 28 23:57:38 2008 UTC vs.
Revision 1.194 by root, Sun Mar 22 03:56:37 2009 UTC