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Revision 1.99 by root, Tue Jul 8 09:37:37 2008 UTC vs.
Revision 1.116 by root, Sat Jun 13 15:11:54 2009 UTC

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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
81no warnings;
76use strict; 82use strict;
77 83
78BEGIN { 84BEGIN {
79 our $VERSION = '3.42'; 85 our $VERSION = '3.6';
80 use XSLoader; 86 use XSLoader;
81 XSLoader::load "EV", $VERSION; 87 XSLoader::load "EV", $VERSION;
82} 88}
83 89
84@EV::IO::ISA = 90@EV::IO::ISA =
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111default loop as this is fastest (perl-wise), best supported by other 117default loop as this is fastest (perl-wise), best supported by other
112modules (e.g. AnyEvent or Coro) and most portable event loop. 118modules (e.g. AnyEvent or Coro) and most portable event loop.
113 119
114For specific programs you can create additional event loops dynamically. 120For specific programs you can create additional event loops dynamically.
115 121
116If you want to take avdantage of kqueue (which often works properly for 122If 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 123sockets 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 124I<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 125will 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. 126the section about embed watchers for an example on how to achieve that.
121 127
122=over 4 128=over 4
123 129
124=item $loop = new EV::loop [$flags] 130=item $loop = new EV::Loop [$flags]
125 131
126Create a new event loop as per the specified flags. Please refer to the 132Create a new event loop as per the specified flags. Please refer to
127C<ev_loop_new ()> function description in the libev documentation 133the 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>) 134(L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTIONS>,
129for more info. 135or locally-installed as F<EV::libev> manpage) for more info.
130 136
131The loop will automatically be destroyed when it is no longer referenced 137The loop will automatically be destroyed when it is no longer referenced
132by any watcher and the loop object goes out of scope. 138by any watcher and the loop object goes out of scope.
133 139
134Using C<EV::FLAG_FORKCHECK> is recommended, as only the default event loop 140If you are not embedding the loop, then Using C<EV::FLAG_FORKCHECK>
135is protected by this module. 141is recommended, as only the default event loop is protected by this
142module. If you I<are> embedding this loop in the default loop, this is not
143necessary, as C<EV::embed> automatically does the right thing on fork.
136 144
137=item $loop->loop_fork 145=item $loop->loop_fork
138 146
139Must be called after a fork in the child, before entering or continuing 147Must 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 148the event loop. An alternative is to use C<EV::FLAG_FORKCHECK> which calls
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191=item $time = EV::now 199=item $time = EV::now
192 200
193=item $time = $loop->now 201=item $time = $loop->now
194 202
195Returns the time the last event loop iteration has been started. This 203Returns 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 204is the time that (relative) timers are based on, and referring to it is
197usually faster then calling EV::time. 205usually faster then calling EV::time.
198 206
207=item EV::now_update
208
209=item $loop->now_update
210
211Establishes the current time by querying the kernel, updating the time
212returned by C<EV::now> in the progress. This is a costly operation and
213is usually done automatically within C<EV::loop>.
214
215This function is rarely useful, but when some event callback runs for a
216very long time without entering the event loop, updating libev's idea of
217the current time is a good idea.
218
219=item EV::suspend
220
221=item $loop->suspend
222
223=item EV::resume
224
225=item $loop->resume
226
227These two functions suspend and resume a loop, for use when the loop is
228not used for a while and timeouts should not be processed.
229
230A typical use case would be an interactive program such as a game: When
231the user presses C<^Z> to suspend the game and resumes it an hour later it
232would be best to handle timeouts as if no time had actually passed while
233the program was suspended. This can be achieved by calling C<suspend>
234in your C<SIGTSTP> handler, sending yourself a C<SIGSTOP> and calling
235C<resume> directly afterwards to resume timer processing.
236
237Effectively, all C<timer> watchers will be delayed by the time spend
238between C<suspend> and C<resume>, and all C<periodic> watchers
239will be rescheduled (that is, they will lose any events that would have
240occured while suspended).
241
242After calling C<suspend> you B<must not> call I<any> function on the given
243loop other than C<resume>, and you B<must not> call C<resume>
244without a previous call to C<suspend>.
245
246Calling C<suspend>/C<resume> has the side effect of updating the event
247loop time (see C<now_update>).
248
199=item $backend = EV::backend 249=item $backend = EV::backend
200 250
201=item $backend = $loop->backend 251=item $backend = $loop->backend
202 252
203Returns an integer describing the backend used by libev (EV::METHOD_SELECT 253Returns an integer describing the backend used by libev (EV::BACKEND_SELECT
204or EV::METHOD_EPOLL). 254or EV::BACKEND_EPOLL).
205 255
206=item EV::loop [$flags] 256=item EV::loop [$flags]
207 257
208=item $loop->loop ([$flags]) 258=item $loop->loop ([$flags])
209 259
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229=item $count = EV::loop_count 279=item $count = EV::loop_count
230 280
231=item $count = $loop->loop_count 281=item $count = $loop->loop_count
232 282
233Return the number of times the event loop has polled for new 283Return the number of times the event loop has polled for new
234events. Sometiems useful as a generation counter. 284events. Sometimes useful as a generation counter.
235 285
236=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents) 286=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
237 287
238=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents)) 288=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
239 289
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279 329
280=item $loop->set_timeout_collect_interval ($time) 330=item $loop->set_timeout_collect_interval ($time)
281 331
282These advanced functions set the minimum block interval when polling for I/O events and the minimum 332These 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 333wait 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 334L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP>
285a more detailed discussion. 335(locally installed as F<EV::libev>) for a more detailed discussion.
286 336
287=back 337=back
288 338
289 339
290=head1 WATCHER OBJECTS 340=head1 WATCHER OBJECTS
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303called with at least two arguments: the watcher and a bitmask of received 353called with at least two arguments: the watcher and a bitmask of received
304events. 354events.
305 355
306Each watcher type has its associated bit in revents, so you can use the 356Each 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 357same callback for multiple watchers. The event mask is named after the
308type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, 358type, 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 359EV::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 360(which can set both EV::READ and EV::WRITE bits), and EV::timer (which
311uses EV::TIMEOUT). 361uses EV::TIMEOUT).
312 362
313In the rare case where one wants to create a watcher but not start it at 363In the rare case where one wants to create a watcher but not start it at
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409because you happen to have this long-running UDP port watcher. 459because you happen to have this long-running UDP port watcher.
410 460
411In this case you can clear the keepalive status, which means that even 461In 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. 462though your watcher is active, it won't keep C<EV::loop> from returning.
413 463
414The initial value for keepalive is true (enabled), and you cna change it 464The initial value for keepalive is true (enabled), and you can change it
415any time. 465any time.
416 466
417Example: Register an I/O watcher for some UDP socket but do not keep the 467Example: Register an I/O watcher for some UDP socket but do not keep the
418event loop from running just because of that watcher. 468event loop from running just because of that watcher.
419 469
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913 # make the dispatcher handle any new stuff 963 # make the dispatcher handle any new stuff
914 ... not shown 964 ... not shown
915 }; 965 };
916 966
917The callbacks of the created watchers will not be called as the watchers 967The callbacks of the created watchers will not be called as the watchers
918are destroyed before this cna happen (remember EV::check gets called 968are destroyed before this can happen (remember EV::check gets called
919first). 969first).
920 970
921The C<check_ns> variant doesn't start (activate) the newly created watcher. 971The C<check_ns> variant doesn't start (activate) the newly created watcher.
922 972
923=back 973=back
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954loop, other types of watchers might be handled in a delayed or incorrect 1004loop, other types of watchers might be handled in a delayed or incorrect
955fashion and must not be used). 1005fashion and must not be used).
956 1006
957See the libev documentation at 1007See the libev documentation at
958L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_> 1008L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_>
959for more details. 1009(locally installed as F<EV::libev>) for more details.
960 1010
961In short, this watcher is most useful on BSD systems without working 1011In short, this watcher is most useful on BSD systems without working
962kqueue to still be able to handle a large number of sockets: 1012kqueue to still be able to handle a large number of sockets:
963 1013
964 my $socket_loop; 1014 my $socket_loop;
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975 # use the default loop otherwise 1025 # use the default loop otherwise
976 $socket_loop ||= EV::default_loop; 1026 $socket_loop ||= EV::default_loop;
977 1027
978=over 4 1028=over 4
979 1029
980=item $w = EV::embed $otherloop, $callback 1030=item $w = EV::embed $otherloop[, $callback]
981 1031
982=item $w = EV::embed_ns $otherloop, $callback 1032=item $w = EV::embed_ns $otherloop[, $callback]
983 1033
984=item $w = $loop->embed ($otherloop, $callback) 1034=item $w = $loop->embed ($otherloop[, $callback])
985 1035
986=item $w = $loop->embed_ns ($otherloop, $callback) 1036=item $w = $loop->embed_ns ($otherloop[, $callback])
987 1037
988Call the callback when the embedded event loop (C<$otherloop>) has any 1038Call 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 1039I/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 1040embedded event loop will be managed automatically (which is recommended),
991automatically. 1041otherwise you have to invoke C<sweep> yourself.
992 1042
993The C<embed_ns> variant doesn't start (activate) the newly created watcher. 1043The C<embed_ns> variant doesn't start (activate) the newly created watcher.
994 1044
995=back 1045=back
996 1046
997=head3 ASYNC WATCHERS - how to wake up another event loop 1047=head3 ASYNC WATCHERS - how to wake up another event loop
998 1048
999Async watchers are provided by EV, but have little use in perl directly, as perl 1049Async watchers are provided by EV, but have little use in perl directly,
1000neither supports threads nor direct access to signal handlers or other 1050as perl neither supports threads running in parallel nor direct access to
1001contexts where they could be of value. 1051signal handlers or other contexts where they could be of value.
1002 1052
1003It is, however, possible to use them from the XS level. 1053It is, however, possible to use them from the XS level.
1004 1054
1005Please see the libev documentation for further details. 1055Please see the libev documentation for further details.
1006 1056
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1034 my $async_check = EV::check sub { }; 1084 my $async_check = EV::check sub { };
1035 1085
1036This ensures that perl gets into control for a short time to handle any 1086This ensures that perl gets into control for a short time to handle any
1037pending signals, and also ensures (slightly) slower overall operation. 1087pending signals, and also ensures (slightly) slower overall operation.
1038 1088
1039=head1 THREADS 1089=head1 ITHREADS
1040 1090
1041Threads are not supported by this module in any way. Perl pseudo-threads 1091Ithreads 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 1092is evil stuff and must die. Real threads as provided by Coro are fully
1043on thread support for it. 1093supported (and enhanced support is available via L<Coro::EV>).
1044 1094
1045=head1 FORK 1095=head1 FORK
1046 1096
1047Most of the "improved" event delivering mechanisms of modern operating 1097Most of the "improved" event delivering mechanisms of modern operating
1048systems have quite a few problems with fork(2) (to put it bluntly: it is 1098systems have quite a few problems with fork(2) (to put it bluntly: it is

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