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Revision 1.126 by root, Tue Mar 16 17:11:48 2010 UTC

55 55
56=head1 DESCRIPTION 56=head1 DESCRIPTION
57 57
58This module provides an interface to libev 58This module provides an interface to libev
59(L<http://software.schmorp.de/pkg/libev.html>). While the documentation 59(L<http://software.schmorp.de/pkg/libev.html>). While the documentation
60below is comprehensive, one might also consult the documentation of libev 60below is comprehensive, one might also consult the documentation of
61itself (L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod>) for more 61libev itself (L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod> or
62subtle details on watcher semantics or some discussion on the available 62F<perldoc EV::libev>) for more subtle details on watcher semantics or some
63backends, or how to force a specific backend with C<LIBEV_FLAGS>, or just 63discussion on the available backends, or how to force a specific backend
64about in any case because it has much more detailed information. 64with C<LIBEV_FLAGS>, or just about in any case because it has much more
65detailed information.
65 66
66This module is very fast and scalable. It is actually so fast that you 67This module is very fast and scalable. It is actually so fast that you
67can use it through the L<AnyEvent> module, stay portable to other event 68can use it through the L<AnyEvent> module, stay portable to other event
68loops (if you don't rely on any watcher types not available through it) 69loops (if you don't rely on any watcher types not available through it)
69and still be faster than with any other event loop currently supported in 70and still be faster than with any other event loop currently supported in
70Perl. 71Perl.
71 72
73=head2 MODULE EXPORTS
74
75This module does not export any symbols.
76
72=cut 77=cut
73 78
74package EV; 79package EV;
75 80
76use strict; 81use common::sense;
77 82
78BEGIN { 83BEGIN {
79 our $VERSION = '3.42'; 84 our $VERSION = '4.00';
80 use XSLoader; 85 use XSLoader;
81 XSLoader::load "EV", $VERSION; 86 XSLoader::load "EV", $VERSION;
82} 87}
83 88
84@EV::IO::ISA = 89@EV::IO::ISA =
111default loop as this is fastest (perl-wise), best supported by other 116default loop as this is fastest (perl-wise), best supported by other
112modules (e.g. AnyEvent or Coro) and most portable event loop. 117modules (e.g. AnyEvent or Coro) and most portable event loop.
113 118
114For specific programs you can create additional event loops dynamically. 119For specific programs you can create additional event loops dynamically.
115 120
116If you want to take avdantage of kqueue (which often works properly for 121If you want to take advantage of kqueue (which often works properly for
117sockets only) even though the default loop doesn't enable it, you can 122sockets only) even though the default loop doesn't enable it, you can
118I<embed> a kqueue loop into the default loop: running the default loop 123I<embed> a kqueue loop into the default loop: running the default loop
119will then also service the kqueue loop to some extent. See the example in 124will then also service the kqueue loop to some extent. See the example in
120the section about embed watchers for an example on how to achieve that. 125the section about embed watchers for an example on how to achieve that.
121 126
122=over 4 127=over 4
123 128
124=item $loop = new EV::loop [$flags] 129=item $loop = new EV::Loop [$flags]
125 130
126Create a new event loop as per the specified flags. Please refer to the 131Create a new event loop as per the specified flags. Please refer to
127C<ev_loop_new ()> function description in the libev documentation 132the C<ev_loop_new ()> function description in the libev documentation
128(L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTIONS>) 133(L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTIONS>,
129for more info. 134or locally-installed as F<EV::libev> manpage) for more info.
130 135
131The loop will automatically be destroyed when it is no longer referenced 136The loop will automatically be destroyed when it is no longer referenced
132by any watcher and the loop object goes out of scope. 137by any watcher and the loop object goes out of scope.
133 138
134Using C<EV::FLAG_FORKCHECK> is recommended, as only the default event loop 139If you are not embedding the loop, then Using C<EV::FLAG_FORKCHECK>
135is protected by this module. 140is recommended, as only the default event loop is protected by this
141module. If you I<are> embedding this loop in the default loop, this is not
142necessary, as C<EV::embed> automatically does the right thing on fork.
136 143
137=item $loop->loop_fork 144=item $loop->loop_fork
138 145
139Must be called after a fork in the child, before entering or continuing 146Must be called after a fork in the child, before entering or continuing
140the event loop. An alternative is to use C<EV::FLAG_FORKCHECK> which calls 147the event loop. An alternative is to use C<EV::FLAG_FORKCHECK> which calls
191=item $time = EV::now 198=item $time = EV::now
192 199
193=item $time = $loop->now 200=item $time = $loop->now
194 201
195Returns the time the last event loop iteration has been started. This 202Returns the time the last event loop iteration has been started. This
196is the time that (relative) timers are based on, and refering to it is 203is the time that (relative) timers are based on, and referring to it is
197usually faster then calling EV::time. 204usually faster then calling EV::time.
198 205
206=item EV::now_update
207
208=item $loop->now_update
209
210Establishes the current time by querying the kernel, updating the time
211returned by C<EV::now> in the progress. This is a costly operation and
212is usually done automatically within C<EV::loop>.
213
214This function is rarely useful, but when some event callback runs for a
215very long time without entering the event loop, updating libev's idea of
216the current time is a good idea.
217
218=item EV::suspend
219
220=item $loop->suspend
221
222=item EV::resume
223
224=item $loop->resume
225
226These two functions suspend and resume a loop, for use when the loop is
227not used for a while and timeouts should not be processed.
228
229A typical use case would be an interactive program such as a game: When
230the user presses C<^Z> to suspend the game and resumes it an hour later it
231would be best to handle timeouts as if no time had actually passed while
232the program was suspended. This can be achieved by calling C<suspend>
233in your C<SIGTSTP> handler, sending yourself a C<SIGSTOP> and calling
234C<resume> directly afterwards to resume timer processing.
235
236Effectively, all C<timer> watchers will be delayed by the time spend
237between C<suspend> and C<resume>, and all C<periodic> watchers
238will be rescheduled (that is, they will lose any events that would have
239occured while suspended).
240
241After calling C<suspend> you B<must not> call I<any> function on the given
242loop other than C<resume>, and you B<must not> call C<resume>
243without a previous call to C<suspend>.
244
245Calling C<suspend>/C<resume> has the side effect of updating the event
246loop time (see C<now_update>).
247
199=item $backend = EV::backend 248=item $backend = EV::backend
200 249
201=item $backend = $loop->backend 250=item $backend = $loop->backend
202 251
203Returns an integer describing the backend used by libev (EV::METHOD_SELECT 252Returns an integer describing the backend used by libev (EV::BACKEND_SELECT
204or EV::METHOD_EPOLL). 253or EV::BACKEND_EPOLL).
205 254
206=item EV::loop [$flags] 255=item EV::loop [$flags]
207 256
208=item $loop->loop ([$flags]) 257=item $loop->loop ([$flags])
209 258
229=item $count = EV::loop_count 278=item $count = EV::loop_count
230 279
231=item $count = $loop->loop_count 280=item $count = $loop->loop_count
232 281
233Return the number of times the event loop has polled for new 282Return the number of times the event loop has polled for new
234events. Sometiems useful as a generation counter. 283events. Sometimes useful as a generation counter.
235 284
236=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents) 285=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
237 286
238=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents)) 287=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
239 288
250timeout. Otherwise a EV::timer with this value will be started. 299timeout. Otherwise a EV::timer with this value will be started.
251 300
252When an error occurs or either the timeout or I/O watcher triggers, then 301When an error occurs or either the timeout or I/O watcher triggers, then
253the callback will be called with the received event set (in general 302the callback will be called with the received event set (in general
254you can expect it to be a combination of C<EV::ERROR>, C<EV::READ>, 303you can expect it to be a combination of C<EV::ERROR>, C<EV::READ>,
255C<EV::WRITE> and C<EV::TIMEOUT>). 304C<EV::WRITE> and C<EV::TIMER>).
256 305
257EV::once doesn't return anything: the watchers stay active till either 306EV::once doesn't return anything: the watchers stay active till either
258of them triggers, then they will be stopped and freed, and the callback 307of them triggers, then they will be stopped and freed, and the callback
259invoked. 308invoked.
260 309
279 328
280=item $loop->set_timeout_collect_interval ($time) 329=item $loop->set_timeout_collect_interval ($time)
281 330
282These advanced functions set the minimum block interval when polling for I/O events and the minimum 331These advanced functions set the minimum block interval when polling for I/O events and the minimum
283wait interval for timer events. See the libev documentation at 332wait interval for timer events. See the libev documentation at
284L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP> for 333L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP>
285a more detailed discussion. 334(locally installed as F<EV::libev>) for a more detailed discussion.
335
336=item $count = EV::pending_count
337
338=item $count = $loop->pending_count
339
340Returns the number of currently pending watchers.
341
342=item EV::invoke_pending
343
344=item $loop->invoke_pending
345
346Invoke all currently pending watchers.
286 347
287=back 348=back
288 349
289 350
290=head1 WATCHER OBJECTS 351=head1 WATCHER OBJECTS
303called with at least two arguments: the watcher and a bitmask of received 364called with at least two arguments: the watcher and a bitmask of received
304events. 365events.
305 366
306Each watcher type has its associated bit in revents, so you can use the 367Each watcher type has its associated bit in revents, so you can use the
307same callback for multiple watchers. The event mask is named after the 368same callback for multiple watchers. The event mask is named after the
308type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, 369type, i.e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE,
309EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events 370EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events
310(which can set both EV::READ and EV::WRITE bits), and EV::timer (which 371(which can set both EV::READ and EV::WRITE bits).
311uses EV::TIMEOUT).
312 372
313In the rare case where one wants to create a watcher but not start it at 373In the rare case where one wants to create a watcher but not start it at
314the same time, each constructor has a variant with a trailing C<_ns> in 374the same time, each constructor has a variant with a trailing C<_ns> in
315its name, e.g. EV::io has a non-starting variant EV::io_ns and so on. 375its name, e.g. EV::io has a non-starting variant EV::io_ns and so on.
316 376
395 455
396=item $previous_state = $w->keepalive ($bool) 456=item $previous_state = $w->keepalive ($bool)
397 457
398Normally, C<EV::loop> will return when there are no active watchers 458Normally, C<EV::loop> will return when there are no active watchers
399(which is a "deadlock" because no progress can be made anymore). This is 459(which is a "deadlock" because no progress can be made anymore). This is
400convinient because it allows you to start your watchers (and your jobs), 460convenient because it allows you to start your watchers (and your jobs),
401call C<EV::loop> once and when it returns you know that all your jobs are 461call C<EV::loop> once and when it returns you know that all your jobs are
402finished (or they forgot to register some watchers for their task :). 462finished (or they forgot to register some watchers for their task :).
403 463
404Sometimes, however, this gets in your way, for example when the module 464Sometimes, however, this gets in your way, for example when the module
405that calls C<EV::loop> (usually the main program) is not the same module 465that calls C<EV::loop> (usually the main program) is not the same module
409because you happen to have this long-running UDP port watcher. 469because you happen to have this long-running UDP port watcher.
410 470
411In this case you can clear the keepalive status, which means that even 471In this case you can clear the keepalive status, which means that even
412though your watcher is active, it won't keep C<EV::loop> from returning. 472though your watcher is active, it won't keep C<EV::loop> from returning.
413 473
414The initial value for keepalive is true (enabled), and you cna change it 474The initial value for keepalive is true (enabled), and you can change it
415any time. 475any time.
416 476
417Example: Register an I/O watcher for some UDP socket but do not keep the 477Example: Register an I/O watcher for some UDP socket but do not keep the
418event loop from running just because of that watcher. 478event loop from running just because of that watcher.
419 479
637 697
638=item $w = EV::signal $signal, $callback 698=item $w = EV::signal $signal, $callback
639 699
640=item $w = EV::signal_ns $signal, $callback 700=item $w = EV::signal_ns $signal, $callback
641 701
702=item $w = $loop->signal ($signal, $callback)
703
704=item $w = $loop->signal_ns ($signal, $callback)
705
642Call the callback when $signal is received (the signal can be specified by 706Call the callback when $signal is received (the signal can be specified by
643number or by name, just as with C<kill> or C<%SIG>). 707number or by name, just as with C<kill> or C<%SIG>).
708
709Only one event loop can grab a given signal - attempting to grab the same
710signal from two EV loops will crash the program immediately or cause data
711corruption.
644 712
645EV will grab the signal for the process (the kernel only allows one 713EV will grab the signal for the process (the kernel only allows one
646component to receive a signal at a time) when you start a signal watcher, 714component to receive a signal at a time) when you start a signal watcher,
647and removes it again when you stop it. Perl does the same when you 715and removes it again when you stop it. Perl does the same when you
648add/remove callbacks to C<%SIG>, so watch out. 716add/remove callbacks to C<%SIG>, so watch out.
913 # make the dispatcher handle any new stuff 981 # make the dispatcher handle any new stuff
914 ... not shown 982 ... not shown
915 }; 983 };
916 984
917The callbacks of the created watchers will not be called as the watchers 985The callbacks of the created watchers will not be called as the watchers
918are destroyed before this cna happen (remember EV::check gets called 986are destroyed before this can happen (remember EV::check gets called
919first). 987first).
920 988
921The C<check_ns> variant doesn't start (activate) the newly created watcher. 989The C<check_ns> variant doesn't start (activate) the newly created watcher.
922 990
923=back 991=back
954loop, other types of watchers might be handled in a delayed or incorrect 1022loop, other types of watchers might be handled in a delayed or incorrect
955fashion and must not be used). 1023fashion and must not be used).
956 1024
957See the libev documentation at 1025See the libev documentation at
958L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_> 1026L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_>
959for more details. 1027(locally installed as F<EV::libev>) for more details.
960 1028
961In short, this watcher is most useful on BSD systems without working 1029In short, this watcher is most useful on BSD systems without working
962kqueue to still be able to handle a large number of sockets: 1030kqueue to still be able to handle a large number of sockets:
963 1031
964 my $socket_loop; 1032 my $socket_loop;
975 # use the default loop otherwise 1043 # use the default loop otherwise
976 $socket_loop ||= EV::default_loop; 1044 $socket_loop ||= EV::default_loop;
977 1045
978=over 4 1046=over 4
979 1047
980=item $w = EV::embed $otherloop, $callback 1048=item $w = EV::embed $otherloop[, $callback]
981 1049
982=item $w = EV::embed_ns $otherloop, $callback 1050=item $w = EV::embed_ns $otherloop[, $callback]
983 1051
984=item $w = $loop->embed ($otherloop, $callback) 1052=item $w = $loop->embed ($otherloop[, $callback])
985 1053
986=item $w = $loop->embed_ns ($otherloop, $callback) 1054=item $w = $loop->embed_ns ($otherloop[, $callback])
987 1055
988Call the callback when the embedded event loop (C<$otherloop>) has any 1056Call the callback when the embedded event loop (C<$otherloop>) has any
989I/O activity. The C<$callback> should alwas be specified as C<undef> in 1057I/O activity. The C<$callback> is optional: if it is missing, then the
990this version of EV, which means the embedded event loop will be managed 1058embedded event loop will be managed automatically (which is recommended),
991automatically. 1059otherwise you have to invoke C<sweep> yourself.
992 1060
993The C<embed_ns> variant doesn't start (activate) the newly created watcher. 1061The C<embed_ns> variant doesn't start (activate) the newly created watcher.
994 1062
995=back 1063=back
996 1064
997=head3 ASYNC WATCHERS - how to wake up another event loop 1065=head3 ASYNC WATCHERS - how to wake up another event loop
998 1066
999Async watchers are provided by EV, but have little use in perl directly, as perl 1067Async watchers are provided by EV, but have little use in perl directly,
1000neither supports threads nor direct access to signal handlers or other 1068as perl neither supports threads running in parallel nor direct access to
1001contexts where they could be of value. 1069signal handlers or other contexts where they could be of value.
1002 1070
1003It is, however, possible to use them from the XS level. 1071It is, however, possible to use them from the XS level.
1004 1072
1005Please see the libev documentation for further details. 1073Please see the libev documentation for further details.
1006 1074
1034 my $async_check = EV::check sub { }; 1102 my $async_check = EV::check sub { };
1035 1103
1036This ensures that perl gets into control for a short time to handle any 1104This ensures that perl gets into control for a short time to handle any
1037pending signals, and also ensures (slightly) slower overall operation. 1105pending signals, and also ensures (slightly) slower overall operation.
1038 1106
1039=head1 THREADS 1107=head1 ITHREADS
1040 1108
1041Threads are not supported by this module in any way. Perl pseudo-threads 1109Ithreads are not supported by this module in any way. Perl pseudo-threads
1042is evil stuff and must die. As soon as Perl gains real threads I will work 1110is evil stuff and must die. Real threads as provided by Coro are fully
1043on thread support for it. 1111supported (and enhanced support is available via L<Coro::EV>).
1044 1112
1045=head1 FORK 1113=head1 FORK
1046 1114
1047Most of the "improved" event delivering mechanisms of modern operating 1115Most of the "improved" event delivering mechanisms of modern operating
1048systems have quite a few problems with fork(2) (to put it bluntly: it is 1116systems have quite a few problems with fork(2) (to put it bluntly: it is

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