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Revision 1.98 by root, Sat May 31 23:17:50 2008 UTC vs.
Revision 1.116 by root, Sat Jun 13 15:11:54 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
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 =
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
116=over 4 122If you want to take advantage of kqueue (which often works properly for
123sockets only) even though the default loop doesn't enable it, you can
124I<embed> a kqueue loop into the default loop: running the default loop
125will then also service the kqueue loop to some extent. See the example in
126the section about embed watchers for an example on how to achieve that.
117 127
128=over 4
129
118=item $loop = new EV::loop [$flags] 130=item $loop = new EV::Loop [$flags]
119 131
120Create 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
121C<ev_loop_new ()> function description in the libev documentation 133the C<ev_loop_new ()> function description in the libev documentation
122(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>,
123for more info. 135or locally-installed as F<EV::libev> manpage) for more info.
124 136
125The loop will automatically be destroyed when it is no longer referenced 137The loop will automatically be destroyed when it is no longer referenced
126by any watcher and the loop object goes out of scope. 138by any watcher and the loop object goes out of scope.
127 139
128Using 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>
129is 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.
130 144
131=item $loop->loop_fork 145=item $loop->loop_fork
132 146
133Must 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
134the 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
136documentation). 150documentation).
137 151
138=item $loop->loop_verify 152=item $loop->loop_verify
139 153
140Calls C<ev_verify> to make internal consistency checks (for debugging 154Calls C<ev_verify> to make internal consistency checks (for debugging
141libev) and abort the program if any data structures wree found to be 155libev) and abort the program if any data structures were found to be
142corrupted. 156corrupted.
143 157
144=item $loop = EV::default_loop [$flags] 158=item $loop = EV::default_loop [$flags]
145 159
146Return the default loop (which is a singleton object). Since this module 160Return the default loop (which is a singleton object). Since this module
147already creates the default loop with default flags, specifying flags here 161already creates the default loop with default flags, specifying flags here
148will not have any effect unless you destroy the default loop. 162will not have any effect unless you destroy the default loop first, which
163isn't supported. So in short: don't do it, and if you break it, you get to
164keep the pieces.
149 165
150=back 166=back
151 167
152 168
153=head1 BASIC INTERFACE 169=head1 BASIC INTERFACE
183=item $time = EV::now 199=item $time = EV::now
184 200
185=item $time = $loop->now 201=item $time = $loop->now
186 202
187Returns the time the last event loop iteration has been started. This 203Returns the time the last event loop iteration has been started. This
188is 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
189usually faster then calling EV::time. 205usually faster then calling EV::time.
190 206
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
191=item $backend = EV::backend 249=item $backend = EV::backend
192 250
193=item $backend = $loop->backend 251=item $backend = $loop->backend
194 252
195Returns an integer describing the backend used by libev (EV::METHOD_SELECT 253Returns an integer describing the backend used by libev (EV::BACKEND_SELECT
196or EV::METHOD_EPOLL). 254or EV::BACKEND_EPOLL).
197 255
198=item EV::loop [$flags] 256=item EV::loop [$flags]
199 257
200=item $loop->loop ([$flags]) 258=item $loop->loop ([$flags])
201 259
221=item $count = EV::loop_count 279=item $count = EV::loop_count
222 280
223=item $count = $loop->loop_count 281=item $count = $loop->loop_count
224 282
225Return the number of times the event loop has polled for new 283Return the number of times the event loop has polled for new
226events. Sometiems useful as a generation counter. 284events. Sometimes useful as a generation counter.
227 285
228=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents) 286=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
229 287
230=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents)) 288=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
231 289
271 329
272=item $loop->set_timeout_collect_interval ($time) 330=item $loop->set_timeout_collect_interval ($time)
273 331
274These 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
275wait interval for timer events. See the libev documentation at 333wait interval for timer events. See the libev documentation at
276L<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>
277a more detailed discussion. 335(locally installed as F<EV::libev>) for a more detailed discussion.
278 336
279=back 337=back
280 338
281 339
282=head1 WATCHER OBJECTS 340=head1 WATCHER OBJECTS
295called 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
296events. 354events.
297 355
298Each 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
299same callback for multiple watchers. The event mask is named after the 357same callback for multiple watchers. The event mask is named after the
300type, 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,
301EV::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
302(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
303uses EV::TIMEOUT). 361uses EV::TIMEOUT).
304 362
305In 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
401because you happen to have this long-running UDP port watcher. 459because you happen to have this long-running UDP port watcher.
402 460
403In 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
404though 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.
405 463
406The 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
407any time. 465any time.
408 466
409Example: 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
410event loop from running just because of that watcher. 468event loop from running just because of that watcher.
411 469
905 # make the dispatcher handle any new stuff 963 # make the dispatcher handle any new stuff
906 ... not shown 964 ... not shown
907 }; 965 };
908 966
909The 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
910are destroyed before this cna happen (remember EV::check gets called 968are destroyed before this can happen (remember EV::check gets called
911first). 969first).
912 970
913The 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.
914 972
915=back 973=back
946loop, 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
947fashion and must not be used). 1005fashion and must not be used).
948 1006
949See the libev documentation at 1007See the libev documentation at
950L<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_>
951for more details. 1009(locally installed as F<EV::libev>) for more details.
952 1010
953In short, this watcher is most useful on BSD systems without working 1011In short, this watcher is most useful on BSD systems without working
954kqueue to still be able to handle a large number of sockets: 1012kqueue to still be able to handle a large number of sockets:
955 1013
956 my $socket_loop; 1014 my $socket_loop;
967 # use the default loop otherwise 1025 # use the default loop otherwise
968 $socket_loop ||= EV::default_loop; 1026 $socket_loop ||= EV::default_loop;
969 1027
970=over 4 1028=over 4
971 1029
972=item $w = EV::embed $otherloop, $callback 1030=item $w = EV::embed $otherloop[, $callback]
973 1031
974=item $w = EV::embed_ns $otherloop, $callback 1032=item $w = EV::embed_ns $otherloop[, $callback]
975 1033
976=item $w = $loop->embed ($otherloop, $callback) 1034=item $w = $loop->embed ($otherloop[, $callback])
977 1035
978=item $w = $loop->embed_ns ($otherloop, $callback) 1036=item $w = $loop->embed_ns ($otherloop[, $callback])
979 1037
980Call the callback when the embedded event loop (C<$otherloop>) has any 1038Call the callback when the embedded event loop (C<$otherloop>) has any
981I/O activity. The C<$callback> should alwas be specified as C<undef> in 1039I/O activity. The C<$callback> is optional: if it is missing, then the
982this version of EV, which means the embedded event loop will be managed 1040embedded event loop will be managed automatically (which is recommended),
983automatically. 1041otherwise you have to invoke C<sweep> yourself.
984 1042
985The 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.
986 1044
987=back 1045=back
988 1046
989=head3 ASYNC WATCHERS - how to wake up another event loop 1047=head3 ASYNC WATCHERS - how to wake up another event loop
990 1048
991Async 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,
992neither supports threads nor direct access to signal handlers or other 1050as perl neither supports threads running in parallel nor direct access to
993contexts where they could be of value. 1051signal handlers or other contexts where they could be of value.
994 1052
995It is, however, possible to use them from the XS level. 1053It is, however, possible to use them from the XS level.
996 1054
997Please see the libev documentation for further details. 1055Please see the libev documentation for further details.
998 1056
1026 my $async_check = EV::check sub { }; 1084 my $async_check = EV::check sub { };
1027 1085
1028This 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
1029pending signals, and also ensures (slightly) slower overall operation. 1087pending signals, and also ensures (slightly) slower overall operation.
1030 1088
1031=head1 THREADS 1089=head1 ITHREADS
1032 1090
1033Threads 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
1034is 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
1035on thread support for it. 1093supported (and enhanced support is available via L<Coro::EV>).
1036 1094
1037=head1 FORK 1095=head1 FORK
1038 1096
1039Most of the "improved" event delivering mechanisms of modern operating 1097Most of the "improved" event delivering mechanisms of modern operating
1040systems 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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