[ViewVC] Diff of: cvs/EV/README

Comparing EV/README (file contents):
Revision 1.31 by root, Wed Nov 19 10:33:32 2008 UTC vs.
Revision 1.37 by root, Sat Oct 23 22:25:44 2010 UTC

…		…
2	EV - perl interface to libev, a high performance full-featured event	2	EV - perl interface to libev, a high performance full-featured event
3	loop	3	loop
4		4
5	SYNOPSIS	5	SYNOPSIS
6	use EV;	6	use EV;
7		7
8	# TIMERS	8	# TIMERS
9		9
10	my $w = EV::timer 2, 0, sub {	10	my $w = EV::timer 2, 0, sub {
11	warn "is called after 2s";	11	warn "is called after 2s";
12	};	12	};
13		13
14	my $w = EV::timer 2, 2, sub {	14	my $w = EV::timer 2, 2, sub {
15	warn "is called roughly every 2s (repeat = 2)";	15	warn "is called roughly every 2s (repeat = 2)";
16	};	16	};
17		17
18	undef $w; # destroy event watcher again	18	undef $w; # destroy event watcher again
19		19
20	my $w = EV::periodic 0, 60, 0, sub {	20	my $w = EV::periodic 0, 60, 0, sub {
21	warn "is called every minute, on the minute, exactly";	21	warn "is called every minute, on the minute, exactly";
22	};	22	};
		23
23		24	# IO
24	# IO	25
25
26	my $w = EV::io *STDIN, EV::READ, sub {	26	my $w = EV::io *STDIN, EV::READ, sub {
27	my ($w, $revents) = @_; # all callbacks receive the watcher and event mask	27	my ($w, $revents) = @_; # all callbacks receive the watcher and event mask
28	warn "stdin is readable, you entered: ", <STDIN>;	28	warn "stdin is readable, you entered: ", <STDIN>;
29	};	29	};
30		30
31	# SIGNALS	31	# SIGNALS
32		32
33	my $w = EV::signal 'QUIT', sub {	33	my $w = EV::signal 'QUIT', sub {
34	warn "sigquit received\n";	34	warn "sigquit received\n";
35	};	35	};
36		36
37	# CHILD/PID STATUS CHANGES	37	# CHILD/PID STATUS CHANGES
38		38
39	my $w = EV::child 666, 0, sub {	39	my $w = EV::child 666, 0, sub {
40	my ($w, $revents) = @_;	40	my ($w, $revents) = @_;
41	my $status = $w->rstatus;	41	my $status = $w->rstatus;
42	};	42	};
43		43
44	# STAT CHANGES	44	# STAT CHANGES
45	my $w = EV::stat "/etc/passwd", 10, sub {	45	my $w = EV::stat "/etc/passwd", 10, sub {
46	my ($w, $revents) = @_;	46	my ($w, $revents) = @_;
47	warn $w->path, " has changed somehow.\n";	47	warn $w->path, " has changed somehow.\n";
48	};	48	};
49		49
50	# MAINLOOP	50	# MAINLOOP
51	EV::loop; # loop until EV::unloop is called or all watchers stop	51	EV::loop; # loop until EV::unloop is called or all watchers stop
52	EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled	52	EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled
53	EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block	53	EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block
		54
		55	BEFORE YOU START USING THIS MODULE
		56	If you only need timer, I/O, signal, child and idle watchers and not the
		57	advanced functionality of this module, consider using AnyEvent instead,
		58	specifically the simplified API described in AE.
		59
		60	When used with EV as backend, the AE API is as fast as the native EV
		61	API, but your programs/modules will still run with many other event
		62	loops.
54		63
55	DESCRIPTION	64	DESCRIPTION
56	This module provides an interface to libev	65	This module provides an interface to libev
57	(<http://software.schmorp.de/pkg/libev.html>). While the documentation	66	(<http://software.schmorp.de/pkg/libev.html>). While the documentation
58	below is comprehensive, one might also consult the documentation of	67	below is comprehensive, one might also consult the documentation of
…		…
66	can use it through the AnyEvent module, stay portable to other event	75	can use it through the AnyEvent module, stay portable to other event
67	loops (if you don't rely on any watcher types not available through it)	76	loops (if you don't rely on any watcher types not available through it)
68	and still be faster than with any other event loop currently supported	77	and still be faster than with any other event loop currently supported
69	in Perl.	78	in Perl.
70		79
		80	PORTING FROM EV 3.X to 4.X
		81	EV version 4 introduces a number of incompatible changes summarised
		82	here. According to the depreciation strategy used by libev, there is a
		83	compatibility layer in place so programs should continue to run
		84	unchanged (the XS interface lacks this layer, so programs using that one
		85	need to be updated).
		86
		87	This compatibility layer will be switched off in some future release.
		88
		89	All changes relevant to Perl are renames of symbols, functions and
		90	methods:
		91
		92	EV::loop => EV::run
		93	EV::LOOP_NONBLOCK => EV::RUN_NOWAIT
		94	EV::LOOP_ONESHOT => EV::RUN_ONCE
		95
		96	EV::unloop => EV::break
		97	EV::UNLOOP_CANCEL => EV::BREAK_CANCEL
		98	EV::UNLOOP_ONE => EV::BREAK_ONE
		99	EV::UNLOOP_ALL => EV::BREAK_ALL
		100
		101	EV::TIMEOUT => EV::TIMER
		102
		103	EV::loop_count => EV::iteration
		104	EV::loop_depth => EV::depth
		105	EV::loop_verify => EV::verify
		106
		107	The loop object methods corresponding to the functions above have been
		108	similarly renamed.
		109
71	MODULE EXPORTS	110	MODULE EXPORTS
72	This module does not export any symbols.	111	This module does not export any symbols.
73		112
74	EVENT LOOPS	113	EVENT LOOPS
75	EV supports multiple event loops: There is a single "default event loop"	114	EV supports multiple event loops: There is a single "default event loop"
…		…
91	embed a kqueue loop into the default loop: running the default loop	130	embed a kqueue loop into the default loop: running the default loop
92	will then also service the kqueue loop to some extent. See the example	131	will then also service the kqueue loop to some extent. See the example
93	in the section about embed watchers for an example on how to achieve	132	in the section about embed watchers for an example on how to achieve
94	that.	133	that.
95		134
96	$loop = new EV::loop [$flags]	135	$loop = new EV::Loop [$flags]
97	Create a new event loop as per the specified flags. Please refer to	136	Create a new event loop as per the specified flags. Please refer to
98	the "ev_loop_new ()" function description in the libev documentation	137	the "ev_loop_new ()" function description in the libev documentation
99	(<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTI	138	(<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTI
100	ONS>, or locally-installed as EV::libev manpage) for more info.	139	ONS>, or locally-installed as EV::libev manpage) for more info.
101		140
…		…
152	$time = $loop->now	191	$time = $loop->now
153	Returns the time the last event loop iteration has been started.	192	Returns the time the last event loop iteration has been started.
154	This is the time that (relative) timers are based on, and referring	193	This is the time that (relative) timers are based on, and referring
155	to it is usually faster then calling EV::time.	194	to it is usually faster then calling EV::time.
156		195
		196	EV::now_update
		197	$loop->now_update
		198	Establishes the current time by querying the kernel, updating the
		199	time returned by "EV::now" in the progress. This is a costly
		200	operation and is usually done automatically within "EV::loop".
		201
		202	This function is rarely useful, but when some event callback runs
		203	for a very long time without entering the event loop, updating
		204	libev's idea of the current time is a good idea.
		205
		206	EV::suspend
		207	$loop->suspend
		208	EV::resume
		209	$loop->resume
		210	These two functions suspend and resume a loop, for use when the loop
		211	is not used for a while and timeouts should not be processed.
		212
		213	A typical use case would be an interactive program such as a game:
		214	When the user presses "^Z" to suspend the game and resumes it an
		215	hour later it would be best to handle timeouts as if no time had
		216	actually passed while the program was suspended. This can be
		217	achieved by calling "suspend" in your "SIGTSTP" handler, sending
		218	yourself a "SIGSTOP" and calling "resume" directly afterwards to
		219	resume timer processing.
		220
		221	Effectively, all "timer" watchers will be delayed by the time spend
		222	between "suspend" and "resume", and all "periodic" watchers will be
		223	rescheduled (that is, they will lose any events that would have
		224	occured while suspended).
		225
		226	After calling "suspend" you must not call any function on the
		227	given loop other than "resume", and you must not call "resume"
		228	without a previous call to "suspend".
		229
		230	Calling "suspend"/"resume" has the side effect of updating the event
		231	loop time (see "now_update").
		232
157	$backend = EV::backend	233	$backend = EV::backend
158	$backend = $loop->backend	234	$backend = $loop->backend
159	Returns an integer describing the backend used by libev	235	Returns an integer describing the backend used by libev
160	(EV::BACKEND_SELECT or EV::BACKEND_EPOLL).	236	(EV::BACKEND_SELECT or EV::BACKEND_EPOLL).
161		237
…		…
198	Otherwise a EV::timer with this value will be started.	274	Otherwise a EV::timer with this value will be started.
199		275
200	When an error occurs or either the timeout or I/O watcher triggers,	276	When an error occurs or either the timeout or I/O watcher triggers,
201	then the callback will be called with the received event set (in	277	then the callback will be called with the received event set (in
202	general you can expect it to be a combination of "EV::ERROR",	278	general you can expect it to be a combination of "EV::ERROR",
203	"EV::READ", "EV::WRITE" and "EV::TIMEOUT").	279	"EV::READ", "EV::WRITE" and "EV::TIMER").
204		280
205	EV::once doesn't return anything: the watchers stay active till	281	EV::once doesn't return anything: the watchers stay active till
206	either of them triggers, then they will be stopped and freed, and	282	either of them triggers, then they will be stopped and freed, and
207	the callback invoked.	283	the callback invoked.
208		284
…		…
226	the libev documentation at	302	the libev documentation at
227	<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONT	303	<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONT
228	ROLLING_THE_EVENT_LOOP> (locally installed as EV::libev) for a more	304	ROLLING_THE_EVENT_LOOP> (locally installed as EV::libev) for a more
229	detailed discussion.	305	detailed discussion.
230		306
		307	$count = EV::pending_count
		308	$count = $loop->pending_count
		309	Returns the number of currently pending watchers.
		310
		311	EV::invoke_pending
		312	$loop->invoke_pending
		313	Invoke all currently pending watchers.
		314
231	WATCHER OBJECTS	315	WATCHER OBJECTS
232	A watcher is an object that gets created to record your interest in some	316	A watcher is an object that gets created to record your interest in some
233	event. For instance, if you want to wait for STDIN to become readable,	317	event. For instance, if you want to wait for STDIN to become readable,
234	you would create an EV::io watcher for that:	318	you would create an EV::io watcher for that:
235		319
…		…
245		329
246	Each watcher type has its associated bit in revents, so you can use the	330	Each watcher type has its associated bit in revents, so you can use the
247	same callback for multiple watchers. The event mask is named after the	331	same callback for multiple watchers. The event mask is named after the
248	type, i.e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE,	332	type, i.e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE,
249	EV::periodic sets EV::PERIODIC and so on, with the exception of I/O	333	EV::periodic sets EV::PERIODIC and so on, with the exception of I/O
250	events (which can set both EV::READ and EV::WRITE bits), and EV::timer	334	events (which can set both EV::READ and EV::WRITE bits).
251	(which uses EV::TIMEOUT).
252		335
253	In the rare case where one wants to create a watcher but not start it at	336	In the rare case where one wants to create a watcher but not start it at
254	the same time, each constructor has a variant with a trailing "_ns" in	337	the same time, each constructor has a variant with a trailing "_ns" in
255	its name, e.g. EV::io has a non-starting variant EV::io_ns and so on.	338	its name, e.g. EV::io has a non-starting variant EV::io_ns and so on.
256		339
…		…
321	the watcher isn't pending it does nothing and returns 0.	404	the watcher isn't pending it does nothing and returns 0.
322		405
323	$previous_state = $w->keepalive ($bool)	406	$previous_state = $w->keepalive ($bool)
324	Normally, "EV::loop" will return when there are no active watchers	407	Normally, "EV::loop" will return when there are no active watchers
325	(which is a "deadlock" because no progress can be made anymore).	408	(which is a "deadlock" because no progress can be made anymore).
326	This is convinient because it allows you to start your watchers (and	409	This is convenient because it allows you to start your watchers (and
327	your jobs), call "EV::loop" once and when it returns you know that	410	your jobs), call "EV::loop" once and when it returns you know that
328	all your jobs are finished (or they forgot to register some watchers	411	all your jobs are finished (or they forgot to register some watchers
329	for their task :).	412	for their task :).
330		413
331	Sometimes, however, this gets in your way, for example when the	414	Sometimes, however, this gets in your way, for example when the
…		…
522	Return the time that the watcher is expected to trigger next.	605	Return the time that the watcher is expected to trigger next.
523		606
524	SIGNAL WATCHERS - signal me when a signal gets signalled!	607	SIGNAL WATCHERS - signal me when a signal gets signalled!
525	$w = EV::signal $signal, $callback	608	$w = EV::signal $signal, $callback
526	$w = EV::signal_ns $signal, $callback	609	$w = EV::signal_ns $signal, $callback
		610	$w = $loop->signal ($signal, $callback)
		611	$w = $loop->signal_ns ($signal, $callback)
527	Call the callback when $signal is received (the signal can be	612	Call the callback when $signal is received (the signal can be
528	specified by number or by name, just as with "kill" or %SIG).	613	specified by number or by name, just as with "kill" or %SIG).
		614
		615	Only one event loop can grab a given signal - attempting to grab the
		616	same signal from two EV loops will crash the program immediately or
		617	cause data corruption.
529		618
530	EV will grab the signal for the process (the kernel only allows one	619	EV will grab the signal for the process (the kernel only allows one
531	component to receive a signal at a time) when you start a signal	620	component to receive a signal at a time) when you start a signal
532	watcher, and removes it again when you stop it. Perl does the same	621	watcher, and removes it again when you stop it. Perl does the same
533	when you add/remove callbacks to %SIG, so watch out.	622	when you add/remove callbacks to %SIG, so watch out.
…		…
707	$w = $loop->check_ns ($callback)	796	$w = $loop->check_ns ($callback)
708	Call the callback just after the process wakes up again (after it	797	Call the callback just after the process wakes up again (after it
709	has gathered events), but before any other callbacks have been	798	has gathered events), but before any other callbacks have been
710	invoked.	799	invoked.
711		800
712	This is used to integrate other event-based software into the EV	801	This can be used to integrate other event-based software into the EV
713	mainloop: You register a prepare callback and in there, you create	802	mainloop: You register a prepare callback and in there, you create
714	io and timer watchers as required by the other software. Here is a	803	io and timer watchers as required by the other software. Here is a
715	real-world example of integrating Net::SNMP (with some details left	804	real-world example of integrating Net::SNMP (with some details left
716	out):	805	out):
717		806
…		…
753	watchers are destroyed before this can happen (remember EV::check	842	watchers are destroyed before this can happen (remember EV::check
754	gets called first).	843	gets called first).
755		844
756	The "check_ns" variant doesn't start (activate) the newly created	845	The "check_ns" variant doesn't start (activate) the newly created
757	watcher.	846	watcher.
		847
		848	EV::CHECK constant issues
		849	Like all other watcher types, there is a bitmask constant for use in
		850	$revents and other places. The "EV::CHECK" is special as it has the
		851	same name as the "CHECK" sub called by Perl. This doesn't cause big
		852	issues on newer perls (beginning with 5.8.9), but it means thatthe
		853	constant must be inlined, i.e. runtime calls will not work. That
		854	means that as long as you always "use EV" and then "EV::CHECK" you
		855	are on the safe side.
758		856
759	FORK WATCHERS - the audacity to resume the event loop after a fork	857	FORK WATCHERS - the audacity to resume the event loop after a fork
760	Fork watchers are called when a "fork ()" was detected. The invocation	858	Fork watchers are called when a "fork ()" was detected. The invocation
761	is done before the event loop blocks next and before "check" watchers	859	is done before the event loop blocks next and before "check" watchers
762	are being called, and only in the child after the fork.	860	are being called, and only in the child after the fork.
…		…
783		881
784	In short, this watcher is most useful on BSD systems without working	882	In short, this watcher is most useful on BSD systems without working
785	kqueue to still be able to handle a large number of sockets:	883	kqueue to still be able to handle a large number of sockets:
786		884
787	my $socket_loop;	885	my $socket_loop;
788		886
789	# check wether we use SELECT or POLL _and_ KQUEUE is supported	887	# check wether we use SELECT or POLL _and_ KQUEUE is supported
790	if (	888	if (
791	(EV::backend & (EV::BACKEND_POLL \| EV::BACKEND_SELECT))	889	(EV::backend & (EV::BACKEND_POLL \| EV::BACKEND_SELECT))
792	&& (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)	890	&& (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE)
793	) {	891	) {
794	# use kqueue for sockets	892	# use kqueue for sockets
795	$socket_loop = new EV::Loop EV::BACKEND_KQUEUE \| EV::FLAG_NOENV;	893	$socket_loop = new EV::Loop EV::BACKEND_KQUEUE \| EV::FLAG_NOENV;
796	}	894	}
797		895
798	# use the default loop otherwise	896	# use the default loop otherwise
799	$socket_loop \|\|= EV::default_loop;	897	$socket_loop \|\|= EV::default_loop;
800		898
801	$w = EV::embed $otherloop[, $callback]	899	$w = EV::embed $otherloop[, $callback]
802	$w = EV::embed_ns $otherloop[, $callback]	900	$w = EV::embed_ns $otherloop[, $callback]
803	$w = $loop->embed ($otherloop[, $callback])	901	$w = $loop->embed ($otherloop[, $callback])
…		…
810	The "embed_ns" variant doesn't start (activate) the newly created	908	The "embed_ns" variant doesn't start (activate) the newly created
811	watcher.	909	watcher.
812		910
813	ASYNC WATCHERS - how to wake up another event loop	911	ASYNC WATCHERS - how to wake up another event loop
814	Async watchers are provided by EV, but have little use in perl directly,	912	Async watchers are provided by EV, but have little use in perl directly,
815	as perl neither supports threads nor direct access to signal handlers or	913	as perl neither supports threads running in parallel nor direct access
816	other contexts where they could be of value.	914	to signal handlers or other contexts where they could be of value.
817		915
818	It is, however, possible to use them from the XS level.	916	It is, however, possible to use them from the XS level.
819		917
820	Please see the libev documentation for further details.	918	Please see the libev documentation for further details.
821		919
…		…
840	my $async_check = EV::check sub { };	938	my $async_check = EV::check sub { };
841		939
842	This ensures that perl gets into control for a short time to handle any	940	This ensures that perl gets into control for a short time to handle any
843	pending signals, and also ensures (slightly) slower overall operation.	941	pending signals, and also ensures (slightly) slower overall operation.
844		942
845	THREADS	943	ITHREADS
846	Threads are not supported by this module in any way. Perl pseudo-threads	944	Ithreads are not supported by this module in any way. Perl
847	is evil stuff and must die. As soon as Perl gains real threads I will	945	pseudo-threads is evil stuff and must die. Real threads as provided by
848	work on thread support for it.	946	Coro are fully supported (and enhanced support is available via
		947	Coro::EV).
849		948
850	FORK	949	FORK
851	Most of the "improved" event delivering mechanisms of modern operating	950	Most of the "improved" event delivering mechanisms of modern operating
852	systems have quite a few problems with fork(2) (to put it bluntly: it is	951	systems have quite a few problems with fork(2) (to put it bluntly: it is
853	not supported and usually destructive). Libev makes it possible to work	952	not supported and usually destructive). Libev makes it possible to work

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Comparing EV/README (file contents): Revision 1.31 by root, Wed Nov 19 10:33:32 2008 UTC vs. Revision 1.37 by root, Sat Oct 23 22:25:44 2010 UTC

Diff Legend

Comparing EV/README (file contents):
Revision 1.31 by root, Wed Nov 19 10:33:32 2008 UTC vs.
Revision 1.37 by root, Sat Oct 23 22:25:44 2010 UTC