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Revision 1.101 by root, Sat Jul 12 22:19:22 2008 UTC vs.
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
76no warnings; 81use common::sense;
77use strict;
78 82
79BEGIN { 83BEGIN {
80 our $VERSION = '3.431'; 84 our $VERSION = '4.00';
81 use XSLoader; 85 use XSLoader;
82 XSLoader::load "EV", $VERSION; 86 XSLoader::load "EV", $VERSION;
83} 87}
84 88
85@EV::IO::ISA = 89@EV::IO::ISA =
112default loop as this is fastest (perl-wise), best supported by other 116default loop as this is fastest (perl-wise), best supported by other
113modules (e.g. AnyEvent or Coro) and most portable event loop. 117modules (e.g. AnyEvent or Coro) and most portable event loop.
114 118
115For specific programs you can create additional event loops dynamically. 119For specific programs you can create additional event loops dynamically.
116 120
117If 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
118sockets 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
119I<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
120will 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
121the 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.
122 126
123=over 4 127=over 4
124 128
125=item $loop = new EV::loop [$flags] 129=item $loop = new EV::Loop [$flags]
126 130
127Create 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
128C<ev_loop_new ()> function description in the libev documentation 132the C<ev_loop_new ()> function description in the libev documentation
129(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>,
130for more info. 134or locally-installed as F<EV::libev> manpage) for more info.
131 135
132The loop will automatically be destroyed when it is no longer referenced 136The loop will automatically be destroyed when it is no longer referenced
133by any watcher and the loop object goes out of scope. 137by any watcher and the loop object goes out of scope.
134 138
135Using 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>
136is 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.
137 143
138=item $loop->loop_fork 144=item $loop->loop_fork
139 145
140Must 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
141the 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
192=item $time = EV::now 198=item $time = EV::now
193 199
194=item $time = $loop->now 200=item $time = $loop->now
195 201
196Returns the time the last event loop iteration has been started. This 202Returns the time the last event loop iteration has been started. This
197is 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
198usually faster then calling EV::time. 204usually faster then calling EV::time.
199 205
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
200=item $backend = EV::backend 248=item $backend = EV::backend
201 249
202=item $backend = $loop->backend 250=item $backend = $loop->backend
203 251
204Returns an integer describing the backend used by libev (EV::METHOD_SELECT 252Returns an integer describing the backend used by libev (EV::BACKEND_SELECT
205or EV::METHOD_EPOLL). 253or EV::BACKEND_EPOLL).
206 254
207=item EV::loop [$flags] 255=item EV::loop [$flags]
208 256
209=item $loop->loop ([$flags]) 257=item $loop->loop ([$flags])
210 258
230=item $count = EV::loop_count 278=item $count = EV::loop_count
231 279
232=item $count = $loop->loop_count 280=item $count = $loop->loop_count
233 281
234Return the number of times the event loop has polled for new 282Return the number of times the event loop has polled for new
235events. Sometiems useful as a generation counter. 283events. Sometimes useful as a generation counter.
236 284
237=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents) 285=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
238 286
239=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents)) 287=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
240 288
251timeout. Otherwise a EV::timer with this value will be started. 299timeout. Otherwise a EV::timer with this value will be started.
252 300
253When 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
254the callback will be called with the received event set (in general 302the callback will be called with the received event set (in general
255you 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>,
256C<EV::WRITE> and C<EV::TIMEOUT>). 304C<EV::WRITE> and C<EV::TIMER>).
257 305
258EV::once doesn't return anything: the watchers stay active till either 306EV::once doesn't return anything: the watchers stay active till either
259of 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
260invoked. 308invoked.
261 309
280 328
281=item $loop->set_timeout_collect_interval ($time) 329=item $loop->set_timeout_collect_interval ($time)
282 330
283These 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
284wait interval for timer events. See the libev documentation at 332wait interval for timer events. See the libev documentation at
285L<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>
286a 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.
287 347
288=back 348=back
289 349
290 350
291=head1 WATCHER OBJECTS 351=head1 WATCHER OBJECTS
304called 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
305events. 365events.
306 366
307Each 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
308same callback for multiple watchers. The event mask is named after the 368same callback for multiple watchers. The event mask is named after the
309type, 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,
310EV::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
311(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).
312uses EV::TIMEOUT).
313 372
314In 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
315the 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
316its 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.
317 376
396 455
397=item $previous_state = $w->keepalive ($bool) 456=item $previous_state = $w->keepalive ($bool)
398 457
399Normally, C<EV::loop> will return when there are no active watchers 458Normally, C<EV::loop> will return when there are no active watchers
400(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
401convinient because it allows you to start your watchers (and your jobs), 460convenient because it allows you to start your watchers (and your jobs),
402call 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
403finished (or they forgot to register some watchers for their task :). 462finished (or they forgot to register some watchers for their task :).
404 463
405Sometimes, however, this gets in your way, for example when the module 464Sometimes, however, this gets in your way, for example when the module
406that 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
410because you happen to have this long-running UDP port watcher. 469because you happen to have this long-running UDP port watcher.
411 470
412In 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
413though 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.
414 473
415The 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
416any time. 475any time.
417 476
418Example: 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
419event loop from running just because of that watcher. 478event loop from running just because of that watcher.
420 479
638 697
639=item $w = EV::signal $signal, $callback 698=item $w = EV::signal $signal, $callback
640 699
641=item $w = EV::signal_ns $signal, $callback 700=item $w = EV::signal_ns $signal, $callback
642 701
702=item $w = $loop->signal ($signal, $callback)
703
704=item $w = $loop->signal_ns ($signal, $callback)
705
643Call 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
644number 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.
645 712
646EV 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
647component 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,
648and 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
649add/remove callbacks to C<%SIG>, so watch out. 716add/remove callbacks to C<%SIG>, so watch out.
914 # make the dispatcher handle any new stuff 981 # make the dispatcher handle any new stuff
915 ... not shown 982 ... not shown
916 }; 983 };
917 984
918The 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
919are destroyed before this cna happen (remember EV::check gets called 986are destroyed before this can happen (remember EV::check gets called
920first). 987first).
921 988
922The 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.
923 990
924=back 991=back
955loop, 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
956fashion and must not be used). 1023fashion and must not be used).
957 1024
958See the libev documentation at 1025See the libev documentation at
959L<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_>
960for more details. 1027(locally installed as F<EV::libev>) for more details.
961 1028
962In short, this watcher is most useful on BSD systems without working 1029In short, this watcher is most useful on BSD systems without working
963kqueue to still be able to handle a large number of sockets: 1030kqueue to still be able to handle a large number of sockets:
964 1031
965 my $socket_loop; 1032 my $socket_loop;
995 1062
996=back 1063=back
997 1064
998=head3 ASYNC WATCHERS - how to wake up another event loop 1065=head3 ASYNC WATCHERS - how to wake up another event loop
999 1066
1000Async 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,
1001neither supports threads nor direct access to signal handlers or other 1068as perl neither supports threads running in parallel nor direct access to
1002contexts where they could be of value. 1069signal handlers or other contexts where they could be of value.
1003 1070
1004It is, however, possible to use them from the XS level. 1071It is, however, possible to use them from the XS level.
1005 1072
1006Please see the libev documentation for further details. 1073Please see the libev documentation for further details.
1007 1074
1035 my $async_check = EV::check sub { }; 1102 my $async_check = EV::check sub { };
1036 1103
1037This 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
1038pending signals, and also ensures (slightly) slower overall operation. 1105pending signals, and also ensures (slightly) slower overall operation.
1039 1106
1040=head1 THREADS 1107=head1 ITHREADS
1041 1108
1042Threads 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
1043is 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
1044on thread support for it. 1111supported (and enhanced support is available via L<Coro::EV>).
1045 1112
1046=head1 FORK 1113=head1 FORK
1047 1114
1048Most of the "improved" event delivering mechanisms of modern operating 1115Most of the "improved" event delivering mechanisms of modern operating
1049systems 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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