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Revision 1.103 by root, Thu Oct 2 07:49:09 2008 UTC vs.
Revision 1.125 by root, Thu Dec 31 06:59:47 2009 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 = '3.44'; 84 our $VERSION = '3.9';
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
135If you are not embedding the loop, then Using C<EV::FLAG_FORKCHECK> 139If you are not embedding the loop, then Using C<EV::FLAG_FORKCHECK>
194=item $time = EV::now 198=item $time = EV::now
195 199
196=item $time = $loop->now 200=item $time = $loop->now
197 201
198Returns the time the last event loop iteration has been started. This 202Returns the time the last event loop iteration has been started. This
199is 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
200usually faster then calling EV::time. 204usually faster then calling EV::time.
201 205
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
202=item $backend = EV::backend 248=item $backend = EV::backend
203 249
204=item $backend = $loop->backend 250=item $backend = $loop->backend
205 251
206Returns an integer describing the backend used by libev (EV::METHOD_SELECT 252Returns an integer describing the backend used by libev (EV::BACKEND_SELECT
207or EV::METHOD_EPOLL). 253or EV::BACKEND_EPOLL).
208 254
209=item EV::loop [$flags] 255=item EV::loop [$flags]
210 256
211=item $loop->loop ([$flags]) 257=item $loop->loop ([$flags])
212 258
232=item $count = EV::loop_count 278=item $count = EV::loop_count
233 279
234=item $count = $loop->loop_count 280=item $count = $loop->loop_count
235 281
236Return the number of times the event loop has polled for new 282Return the number of times the event loop has polled for new
237events. Sometiems useful as a generation counter. 283events. Sometimes useful as a generation counter.
238 284
239=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents) 285=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
240 286
241=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents)) 287=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
242 288
282 328
283=item $loop->set_timeout_collect_interval ($time) 329=item $loop->set_timeout_collect_interval ($time)
284 330
285These 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
286wait interval for timer events. See the libev documentation at 332wait interval for timer events. See the libev documentation at
287L<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>
288a 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.
289 347
290=back 348=back
291 349
292 350
293=head1 WATCHER OBJECTS 351=head1 WATCHER OBJECTS
306called 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
307events. 365events.
308 366
309Each 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
310same callback for multiple watchers. The event mask is named after the 368same callback for multiple watchers. The event mask is named after the
311type, 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,
312EV::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
313(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), and EV::timer (which
314uses EV::TIMEOUT). 372uses EV::TIMEOUT).
315 373
316In the rare case where one wants to create a watcher but not start it at 374In the rare case where one wants to create a watcher but not start it at
398 456
399=item $previous_state = $w->keepalive ($bool) 457=item $previous_state = $w->keepalive ($bool)
400 458
401Normally, C<EV::loop> will return when there are no active watchers 459Normally, C<EV::loop> will return when there are no active watchers
402(which is a "deadlock" because no progress can be made anymore). This is 460(which is a "deadlock" because no progress can be made anymore). This is
403convinient because it allows you to start your watchers (and your jobs), 461convenient because it allows you to start your watchers (and your jobs),
404call C<EV::loop> once and when it returns you know that all your jobs are 462call C<EV::loop> once and when it returns you know that all your jobs are
405finished (or they forgot to register some watchers for their task :). 463finished (or they forgot to register some watchers for their task :).
406 464
407Sometimes, however, this gets in your way, for example when the module 465Sometimes, however, this gets in your way, for example when the module
408that calls C<EV::loop> (usually the main program) is not the same module 466that calls C<EV::loop> (usually the main program) is not the same module
412because you happen to have this long-running UDP port watcher. 470because you happen to have this long-running UDP port watcher.
413 471
414In this case you can clear the keepalive status, which means that even 472In this case you can clear the keepalive status, which means that even
415though your watcher is active, it won't keep C<EV::loop> from returning. 473though your watcher is active, it won't keep C<EV::loop> from returning.
416 474
417The initial value for keepalive is true (enabled), and you cna change it 475The initial value for keepalive is true (enabled), and you can change it
418any time. 476any time.
419 477
420Example: Register an I/O watcher for some UDP socket but do not keep the 478Example: Register an I/O watcher for some UDP socket but do not keep the
421event loop from running just because of that watcher. 479event loop from running just because of that watcher.
422 480
640 698
641=item $w = EV::signal $signal, $callback 699=item $w = EV::signal $signal, $callback
642 700
643=item $w = EV::signal_ns $signal, $callback 701=item $w = EV::signal_ns $signal, $callback
644 702
703=item $w = $loop->signal ($signal, $callback)
704
705=item $w = $loop->signal_ns ($signal, $callback)
706
645Call the callback when $signal is received (the signal can be specified by 707Call the callback when $signal is received (the signal can be specified by
646number or by name, just as with C<kill> or C<%SIG>). 708number or by name, just as with C<kill> or C<%SIG>).
709
710Only one event loop can grab a given signal - attempting to grab the same
711signal from two EV loops will crash the program immediately or cause data
712corruption.
647 713
648EV will grab the signal for the process (the kernel only allows one 714EV will grab the signal for the process (the kernel only allows one
649component to receive a signal at a time) when you start a signal watcher, 715component to receive a signal at a time) when you start a signal watcher,
650and removes it again when you stop it. Perl does the same when you 716and removes it again when you stop it. Perl does the same when you
651add/remove callbacks to C<%SIG>, so watch out. 717add/remove callbacks to C<%SIG>, so watch out.
916 # make the dispatcher handle any new stuff 982 # make the dispatcher handle any new stuff
917 ... not shown 983 ... not shown
918 }; 984 };
919 985
920The callbacks of the created watchers will not be called as the watchers 986The callbacks of the created watchers will not be called as the watchers
921are destroyed before this cna happen (remember EV::check gets called 987are destroyed before this can happen (remember EV::check gets called
922first). 988first).
923 989
924The C<check_ns> variant doesn't start (activate) the newly created watcher. 990The C<check_ns> variant doesn't start (activate) the newly created watcher.
925 991
926=back 992=back
957loop, other types of watchers might be handled in a delayed or incorrect 1023loop, other types of watchers might be handled in a delayed or incorrect
958fashion and must not be used). 1024fashion and must not be used).
959 1025
960See the libev documentation at 1026See the libev documentation at
961L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_> 1027L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_>
962for more details. 1028(locally installed as F<EV::libev>) for more details.
963 1029
964In short, this watcher is most useful on BSD systems without working 1030In short, this watcher is most useful on BSD systems without working
965kqueue to still be able to handle a large number of sockets: 1031kqueue to still be able to handle a large number of sockets:
966 1032
967 my $socket_loop; 1033 my $socket_loop;
997 1063
998=back 1064=back
999 1065
1000=head3 ASYNC WATCHERS - how to wake up another event loop 1066=head3 ASYNC WATCHERS - how to wake up another event loop
1001 1067
1002Async watchers are provided by EV, but have little use in perl directly, as perl 1068Async watchers are provided by EV, but have little use in perl directly,
1003neither supports threads nor direct access to signal handlers or other 1069as perl neither supports threads running in parallel nor direct access to
1004contexts where they could be of value. 1070signal handlers or other contexts where they could be of value.
1005 1071
1006It is, however, possible to use them from the XS level. 1072It is, however, possible to use them from the XS level.
1007 1073
1008Please see the libev documentation for further details. 1074Please see the libev documentation for further details.
1009 1075
1037 my $async_check = EV::check sub { }; 1103 my $async_check = EV::check sub { };
1038 1104
1039This ensures that perl gets into control for a short time to handle any 1105This ensures that perl gets into control for a short time to handle any
1040pending signals, and also ensures (slightly) slower overall operation. 1106pending signals, and also ensures (slightly) slower overall operation.
1041 1107
1042=head1 THREADS 1108=head1 ITHREADS
1043 1109
1044Threads are not supported by this module in any way. Perl pseudo-threads 1110Ithreads are not supported by this module in any way. Perl pseudo-threads
1045is evil stuff and must die. As soon as Perl gains real threads I will work 1111is evil stuff and must die. Real threads as provided by Coro are fully
1046on thread support for it. 1112supported (and enhanced support is available via L<Coro::EV>).
1047 1113
1048=head1 FORK 1114=head1 FORK
1049 1115
1050Most of the "improved" event delivering mechanisms of modern operating 1116Most of the "improved" event delivering mechanisms of modern operating
1051systems have quite a few problems with fork(2) (to put it bluntly: it is 1117systems have quite a few problems with fork(2) (to put it bluntly: it is

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