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Revision 1.104 by root, Thu Oct 2 12:26:25 2008 UTC vs.
Revision 1.123 by root, Sun Aug 9 13:30:41 2009 UTC

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 60below is comprehensive, one might also consult the documentation of
61libev itself (L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod> or 61libev itself (L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod> or
62F<perldoc EV::c_doc>) for more subtle details on watcher semantics or some 62F<perldoc EV::libev>) for more subtle details on watcher semantics or some
63discussion on the available backends, or how to force a specific backend 63discussion on the available backends, or how to force a specific backend
64with C<LIBEV_FLAGS>, or just about in any case because it has much more 64with C<LIBEV_FLAGS>, or just about in any case because it has much more
65detailed information. 65detailed information.
66 66
67This 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
68can 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
69loops (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)
70and 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
71Perl. 71Perl.
72 72
73=head2 MODULE EXPORTS
74
75This module does not export any symbols.
76
73=cut 77=cut
74 78
75package EV; 79package EV;
76 80
77no warnings; 81use common::sense;
78use strict;
79 82
80BEGIN { 83BEGIN {
81 our $VERSION = '3.44'; 84 our $VERSION = '3.8';
82 use XSLoader; 85 use XSLoader;
83 XSLoader::load "EV", $VERSION; 86 XSLoader::load "EV", $VERSION;
84} 87}
85 88
86@EV::IO::ISA = 89@EV::IO::ISA =
113default loop as this is fastest (perl-wise), best supported by other 116default loop as this is fastest (perl-wise), best supported by other
114modules (e.g. AnyEvent or Coro) and most portable event loop. 117modules (e.g. AnyEvent or Coro) and most portable event loop.
115 118
116For specific programs you can create additional event loops dynamically. 119For specific programs you can create additional event loops dynamically.
117 120
118If 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
119sockets 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
120I<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
121will 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
122the 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.
123 126
124=over 4 127=over 4
125 128
126=item $loop = new EV::loop [$flags] 129=item $loop = new EV::Loop [$flags]
127 130
128Create a new event loop as per the specified flags. Please refer to 131Create a new event loop as per the specified flags. Please refer to
129the C<ev_loop_new ()> function description in the libev documentation 132the C<ev_loop_new ()> function description in the libev documentation
130(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>,
131or locally-installed as F<EV::c_doc> manpage) for more info. 134or locally-installed as F<EV::libev> manpage) for more info.
132 135
133The loop will automatically be destroyed when it is no longer referenced 136The loop will automatically be destroyed when it is no longer referenced
134by any watcher and the loop object goes out of scope. 137by any watcher and the loop object goes out of scope.
135 138
136If 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>
195=item $time = EV::now 198=item $time = EV::now
196 199
197=item $time = $loop->now 200=item $time = $loop->now
198 201
199Returns the time the last event loop iteration has been started. This 202Returns the time the last event loop iteration has been started. This
200is 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
201usually faster then calling EV::time. 204usually faster then calling EV::time.
202 205
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
203=item $backend = EV::backend 248=item $backend = EV::backend
204 249
205=item $backend = $loop->backend 250=item $backend = $loop->backend
206 251
207Returns an integer describing the backend used by libev (EV::METHOD_SELECT 252Returns an integer describing the backend used by libev (EV::BACKEND_SELECT
208or EV::METHOD_EPOLL). 253or EV::BACKEND_EPOLL).
209 254
210=item EV::loop [$flags] 255=item EV::loop [$flags]
211 256
212=item $loop->loop ([$flags]) 257=item $loop->loop ([$flags])
213 258
233=item $count = EV::loop_count 278=item $count = EV::loop_count
234 279
235=item $count = $loop->loop_count 280=item $count = $loop->loop_count
236 281
237Return the number of times the event loop has polled for new 282Return the number of times the event loop has polled for new
238events. Sometiems useful as a generation counter. 283events. Sometimes useful as a generation counter.
239 284
240=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents) 285=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
241 286
242=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents)) 287=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
243 288
284=item $loop->set_timeout_collect_interval ($time) 329=item $loop->set_timeout_collect_interval ($time)
285 330
286These 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
287wait interval for timer events. See the libev documentation at 332wait interval for timer events. See the libev documentation at
288L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP> 333L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP>
289(locally installed as F<EV::c_doc>) for a 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.
290 347
291=back 348=back
292 349
293 350
294=head1 WATCHER OBJECTS 351=head1 WATCHER OBJECTS
307called 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
308events. 365events.
309 366
310Each 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
311same callback for multiple watchers. The event mask is named after the 368same callback for multiple watchers. The event mask is named after the
312type, 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,
313EV::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
314(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
315uses EV::TIMEOUT). 372uses EV::TIMEOUT).
316 373
317In 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
413because you happen to have this long-running UDP port watcher. 470because you happen to have this long-running UDP port watcher.
414 471
415In 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
416though 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.
417 474
418The 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
419any time. 476any time.
420 477
421Example: 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
422event loop from running just because of that watcher. 479event loop from running just because of that watcher.
423 480
641 698
642=item $w = EV::signal $signal, $callback 699=item $w = EV::signal $signal, $callback
643 700
644=item $w = EV::signal_ns $signal, $callback 701=item $w = EV::signal_ns $signal, $callback
645 702
703=item $w = $loop->signal ($signal, $callback)
704
705=item $w = $loop->signal_ns ($signal, $callback)
706
646Call 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
647number 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.
648 713
649EV 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
650component 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,
651and 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
652add/remove callbacks to C<%SIG>, so watch out. 717add/remove callbacks to C<%SIG>, so watch out.
917 # make the dispatcher handle any new stuff 982 # make the dispatcher handle any new stuff
918 ... not shown 983 ... not shown
919 }; 984 };
920 985
921The 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
922are destroyed before this cna happen (remember EV::check gets called 987are destroyed before this can happen (remember EV::check gets called
923first). 988first).
924 989
925The 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.
926 991
927=back 992=back
958loop, 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
959fashion and must not be used). 1024fashion and must not be used).
960 1025
961See the libev documentation at 1026See the libev documentation at
962L<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_>
963(locally installed as F<EV::c_doc>) for more details. 1028(locally installed as F<EV::libev>) for more details.
964 1029
965In short, this watcher is most useful on BSD systems without working 1030In short, this watcher is most useful on BSD systems without working
966kqueue to still be able to handle a large number of sockets: 1031kqueue to still be able to handle a large number of sockets:
967 1032
968 my $socket_loop; 1033 my $socket_loop;
998 1063
999=back 1064=back
1000 1065
1001=head3 ASYNC WATCHERS - how to wake up another event loop 1066=head3 ASYNC WATCHERS - how to wake up another event loop
1002 1067
1003Async 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,
1004neither supports threads nor direct access to signal handlers or other 1069as perl neither supports threads running in parallel nor direct access to
1005contexts where they could be of value. 1070signal handlers or other contexts where they could be of value.
1006 1071
1007It is, however, possible to use them from the XS level. 1072It is, however, possible to use them from the XS level.
1008 1073
1009Please see the libev documentation for further details. 1074Please see the libev documentation for further details.
1010 1075
1038 my $async_check = EV::check sub { }; 1103 my $async_check = EV::check sub { };
1039 1104
1040This 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
1041pending signals, and also ensures (slightly) slower overall operation. 1106pending signals, and also ensures (slightly) slower overall operation.
1042 1107
1043=head1 THREADS 1108=head1 ITHREADS
1044 1109
1045Threads 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
1046is 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
1047on thread support for it. 1112supported (and enhanced support is available via L<Coro::EV>).
1048 1113
1049=head1 FORK 1114=head1 FORK
1050 1115
1051Most of the "improved" event delivering mechanisms of modern operating 1116Most of the "improved" event delivering mechanisms of modern operating
1052systems 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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