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Revision 1.166 by root, Wed Aug 16 16:03:37 2023 UTC

… …
47 my ($w, $revents) = @_; 47 my ($w, $revents) = @_;
48 warn $w->path, " has changed somehow.\n"; 48 warn $w->path, " has changed somehow.\n";
49 }; 49 };
50 50
51 # MAINLOOP 51 # MAINLOOP
52 EV::loop; # loop until EV::unloop is called or all watchers stop 52 EV::run; # loop until EV::break is called or all watchers stop
53 EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled 53 EV::run EV::RUN_ONCE; # block until at least one event could be handled
54 EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block 54 EV::run EV::RUN_NOWAIT; # try to handle same events, but do not block
55
56=head1 BEFORE YOU START USING THIS MODULE
57
58If you only need timer, I/O, signal, child and idle watchers and not the
59advanced functionality of this module, consider using L<AnyEvent> instead,
60specifically the simplified API described in L<AE>.
61
62When used with EV as backend, the L<AE> API is as fast as the native L<EV>
63API, but your programs/modules will still run with many other event loops.
55 64
56=head1 DESCRIPTION 65=head1 DESCRIPTION
57 66
58This module provides an interface to libev 67This module provides an interface to libev
59(L<http://software.schmorp.de/pkg/libev.html>). While the documentation 68(L<http://software.schmorp.de/pkg/libev.html>). While the documentation
60below is comprehensive, one might also consult the documentation of libev 69below is comprehensive, one might also consult the documentation of
61itself (L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod>) for more 70libev 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 71F<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 72discussion on the available backends, or how to force a specific backend
64about in any case because it has much more detailed information. 73with C<LIBEV_FLAGS>, or just about in any case because it has much more
74detailed information.
65 75
66This module is very fast and scalable. It is actually so fast that you 76This 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 77can 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) 78loops (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 79and still be faster than with any other event loop currently supported in
70Perl. 80Perl.
71 81
82=head2 PORTING FROM EV 3.X to 4.X
83
84EV version 4 introduces a number of incompatible changes summarised
85here. According to the depreciation strategy used by libev, there is a
86compatibility layer in place so programs should continue to run unchanged
87(the XS interface lacks this layer, so programs using that one need to be
88updated).
89
90This compatibility layer will be switched off in some future release.
91
92All changes relevant to Perl are renames of symbols, functions and
93methods:
94
95 EV::loop => EV::run
96 EV::LOOP_NONBLOCK => EV::RUN_NOWAIT
97 EV::LOOP_ONESHOT => EV::RUN_ONCE
98
99 EV::unloop => EV::break
100 EV::UNLOOP_CANCEL => EV::BREAK_CANCEL
101 EV::UNLOOP_ONE => EV::BREAK_ONE
102 EV::UNLOOP_ALL => EV::BREAK_ALL
103
104 EV::TIMEOUT => EV::TIMER
105
106 EV::loop_count => EV::iteration
107 EV::loop_depth => EV::depth
108 EV::loop_verify => EV::verify
109
110The loop object methods corresponding to the functions above have been
111similarly renamed.
112
113=head2 MODULE EXPORTS
114
115This module does not export any symbols.
116
72=cut 117=cut
73 118
74package EV; 119package EV;
75 120
76no warnings; 121use common::sense;
77use strict;
78 122
79BEGIN { 123BEGIN {
80 our $VERSION = '3.44'; 124 our $VERSION = '4.34';
81 use XSLoader; 125 use XSLoader;
126 local $^W = 0; # avoid spurious warning
82 XSLoader::load "EV", $VERSION; 127 XSLoader::load "EV", $VERSION;
83} 128}
84 129
85@EV::IO::ISA = 130@EV::IO::ISA =
86@EV::Timer::ISA = 131@EV::Timer::ISA =
… …
112default loop as this is fastest (perl-wise), best supported by other 157default loop as this is fastest (perl-wise), best supported by other
113modules (e.g. AnyEvent or Coro) and most portable event loop. 158modules (e.g. AnyEvent or Coro) and most portable event loop.
114 159
115For specific programs you can create additional event loops dynamically. 160For specific programs you can create additional event loops dynamically.
116 161
117If you want to take avdantage of kqueue (which often works properly for 162If 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 163sockets 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 164I<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 165will 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. 166the section about embed watchers for an example on how to achieve that.
122 167
123=over 4 168=over 4
124 169
125=item $loop = new EV::loop [$flags] 170=item $loop = new EV::Loop [$flags]
126 171
127Create a new event loop as per the specified flags. Please refer to the 172Create a new event loop as per the specified flags. Please refer to
128C<ev_loop_new ()> function description in the libev documentation 173the 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>) 174(L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTIONS>,
130for more info. 175or locally-installed as F<EV::libev> manpage) for more info.
131 176
132The loop will automatically be destroyed when it is no longer referenced 177The loop will automatically be destroyed when it is no longer referenced
133by any watcher and the loop object goes out of scope. 178by any watcher and the loop object goes out of scope.
134 179
135Using C<EV::FLAG_FORKCHECK> is recommended, as only the default event loop 180If you are not embedding the loop, then Using C<EV::FLAG_FORKCHECK>
136is protected by this module. 181is recommended, as only the default event loop is protected by this
182module. If you I<are> embedding this loop in the default loop, this is not
183necessary, as C<EV::embed> automatically does the right thing on fork.
137 184
138=item $loop->loop_fork 185=item $loop->loop_fork
139 186
140Must be called after a fork in the child, before entering or continuing 187Must 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 188the event loop. An alternative is to use C<EV::FLAG_FORKCHECK> which calls
142this function automatically, at some performance loss (refer to the libev 189this function automatically, at some performance loss (refer to the libev
143documentation). 190documentation).
144 191
145=item $loop->loop_verify 192=item $loop->verify
146 193
147Calls C<ev_verify> to make internal consistency checks (for debugging 194Calls C<ev_verify> to make internal consistency checks (for debugging
148libev) and abort the program if any data structures were found to be 195libev) and abort the program if any data structures were found to be
149corrupted. 196corrupted.
150 197
… …
192=item $time = EV::now 239=item $time = EV::now
193 240
194=item $time = $loop->now 241=item $time = $loop->now
195 242
196Returns the time the last event loop iteration has been started. This 243Returns 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 244is the time that (relative) timers are based on, and referring to it is
198usually faster then calling EV::time. 245usually faster then calling EV::time.
199 246
247=item EV::now_update
248
249=item $loop->now_update
250
251Establishes the current time by querying the kernel, updating the time
252returned by C<EV::now> in the progress. This is a costly operation and
253is usually done automatically within C<EV::run>.
254
255This function is rarely useful, but when some event callback runs for a
256very long time without entering the event loop, updating libev's idea of
257the current time is a good idea.
258
259=item EV::suspend
260
261=item $loop->suspend
262
263=item EV::resume
264
265=item $loop->resume
266
267These two functions suspend and resume a loop, for use when the loop is
268not used for a while and timeouts should not be processed.
269
270A typical use case would be an interactive program such as a game: When
271the user presses C<^Z> to suspend the game and resumes it an hour later it
272would be best to handle timeouts as if no time had actually passed while
273the program was suspended. This can be achieved by calling C<suspend>
274in your C<SIGTSTP> handler, sending yourself a C<SIGSTOP> and calling
275C<resume> directly afterwards to resume timer processing.
276
277Effectively, all C<timer> watchers will be delayed by the time spend
278between C<suspend> and C<resume>, and all C<periodic> watchers
279will be rescheduled (that is, they will lose any events that would have
280occured while suspended).
281
282After calling C<suspend> you B<must not> call I<any> function on the given
283loop other than C<resume>, and you B<must not> call C<resume>
284without a previous call to C<suspend>.
285
286Calling C<suspend>/C<resume> has the side effect of updating the event
287loop time (see C<now_update>).
288
200=item $backend = EV::backend 289=item $backend = EV::backend
201 290
202=item $backend = $loop->backend 291=item $backend = $loop->backend
203 292
204Returns an integer describing the backend used by libev (EV::METHOD_SELECT 293Returns an integer describing the backend used by libev (EV::BACKEND_SELECT
205or EV::METHOD_EPOLL). 294or EV::BACKEND_EPOLL).
206 295
207=item EV::loop [$flags] 296=item $active = EV::run [$flags]
208 297
209=item $loop->loop ([$flags]) 298=item $active = $loop->run ([$flags])
210 299
211Begin checking for events and calling callbacks. It returns when a 300Begin checking for events and calling callbacks. It returns when a
212callback calls EV::unloop. 301callback calls EV::break or the flags are nonzero (in which case the
302return value is true) or when there are no active watchers which reference
303the loop (keepalive is true), in which case the return value will be
304false. The return value can generally be interpreted as "if true, there is
305more work left to do".
213 306
214The $flags argument can be one of the following: 307The $flags argument can be one of the following:
215 308
216 0 as above 309 0 as above
217 EV::LOOP_ONESHOT block at most once (wait, but do not loop) 310 EV::RUN_ONCE block at most once (wait, but do not loop)
218 EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) 311 EV::RUN_NOWAIT do not block at all (fetch/handle events but do not wait)
219 312
220=item EV::unloop [$how] 313=item EV::break [$how]
221 314
222=item $loop->unloop ([$how]) 315=item $loop->break ([$how])
223 316
224When called with no arguments or an argument of EV::UNLOOP_ONE, makes the 317When called with no arguments or an argument of EV::BREAK_ONE, makes the
225innermost call to EV::loop return. 318innermost call to EV::run return.
226 319
227When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as 320When called with an argument of EV::BREAK_ALL, all calls to EV::run will
228fast as possible. 321return as fast as possible.
229 322
230=item $count = EV::loop_count 323When called with an argument of EV::BREAK_CANCEL, any pending break will
324be cancelled.
231 325
326=item $count = EV::iteration
327
232=item $count = $loop->loop_count 328=item $count = $loop->iteration
233 329
234Return the number of times the event loop has polled for new 330Return the number of times the event loop has polled for new
235events. Sometiems useful as a generation counter. 331events. Sometimes useful as a generation counter.
236 332
237=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents) 333=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
238 334
239=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents)) 335=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents))
240 336
… …
246| EV::WRITE>, indicating the type of I/O event you want to wait for. If 342| EV::WRITE>, indicating the type of I/O event you want to wait for. If
247you do not want to wait for some I/O event, specify C<undef> for 343you do not want to wait for some I/O event, specify C<undef> for
248C<$fh_or_undef> and C<0> for C<$events>). 344C<$fh_or_undef> and C<0> for C<$events>).
249 345
250If timeout is C<undef> or negative, then there will be no 346If timeout is C<undef> or negative, then there will be no
251timeout. Otherwise a EV::timer with this value will be started. 347timeout. Otherwise an C<EV::timer> with this value will be started.
252 348
253When an error occurs or either the timeout or I/O watcher triggers, then 349When 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 350the 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>, 351you can expect it to be a combination of C<EV::ERROR>, C<EV::READ>,
256C<EV::WRITE> and C<EV::TIMEOUT>). 352C<EV::WRITE> and C<EV::TIMER>).
257 353
258EV::once doesn't return anything: the watchers stay active till either 354EV::once doesn't return anything: the watchers stay active till either
259of them triggers, then they will be stopped and freed, and the callback 355of them triggers, then they will be stopped and freed, and the callback
260invoked. 356invoked.
261 357
262=item EV::feed_fd_event ($fd, $revents) 358=item EV::feed_fd_event $fd, $revents
263 359
264=item $loop->feed_fd_event ($fd, $revents) 360=item $loop->feed_fd_event ($fd, $revents)
265 361
266Feed an event on a file descriptor into EV. EV will react to this call as 362Feed an event on a file descriptor into EV. EV will react to this call as
267if the readyness notifications specified by C<$revents> (a combination of 363if the readyness notifications specified by C<$revents> (a combination of
268C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>. 364C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>.
269 365
270=item EV::feed_signal_event ($signal) 366=item EV::feed_signal_event $signal
271 367
272Feed a signal event into EV. EV will react to this call as if the signal 368Feed a signal event into the default loop. EV will react to this call as
273specified by C<$signal> had occured. 369if the signal specified by C<$signal> had occured.
370
371=item EV::feed_signal $signal
372
373Feed a signal event into EV - unlike C<EV::feed_signal_event>, this works
374regardless of which loop has registered the signal, and is mainly useful
375for custom signal implementations.
274 376
275=item EV::set_io_collect_interval $time 377=item EV::set_io_collect_interval $time
276 378
277=item $loop->set_io_collect_interval ($time) 379=item $loop->set_io_collect_interval ($time)
278 380
… …
280 382
281=item $loop->set_timeout_collect_interval ($time) 383=item $loop->set_timeout_collect_interval ($time)
282 384
283These advanced functions set the minimum block interval when polling for I/O events and the minimum 385These 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 386wait 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 387L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP>
286a more detailed discussion. 388(locally installed as F<EV::libev>) for a more detailed discussion.
389
390=item $count = EV::pending_count
391
392=item $count = $loop->pending_count
393
394Returns the number of currently pending watchers.
395
396=item EV::invoke_pending
397
398=item $loop->invoke_pending
399
400Invoke all currently pending watchers.
287 401
288=back 402=back
289 403
290 404
291=head1 WATCHER OBJECTS 405=head1 WATCHER OBJECTS
… …
304called with at least two arguments: the watcher and a bitmask of received 418called with at least two arguments: the watcher and a bitmask of received
305events. 419events.
306 420
307Each watcher type has its associated bit in revents, so you can use the 421Each watcher type has its associated bit in revents, so you can use the
308same callback for multiple watchers. The event mask is named after the 422same callback for multiple watchers. The event mask is named after the
309type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, 423type, i.e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE,
310EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events 424EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events
311(which can set both EV::READ and EV::WRITE bits), and EV::timer (which 425(which can set both EV::READ and EV::WRITE bits).
312uses EV::TIMEOUT).
313 426
314In the rare case where one wants to create a watcher but not start it at 427In the rare case where one wants to create a watcher but not start it at
315the same time, each constructor has a variant with a trailing C<_ns> in 428the same time, each constructor has a variant with a trailing C<_ns> in
316its name, e.g. EV::io has a non-starting variant EV::io_ns and so on. 429its name, e.g. EV::io has a non-starting variant EV::io_ns and so on.
317 430
… …
394returns its C<$revents> bitset (as if its callback was invoked). If the 507returns its C<$revents> bitset (as if its callback was invoked). If the
395watcher isn't pending it does nothing and returns C<0>. 508watcher isn't pending it does nothing and returns C<0>.
396 509
397=item $previous_state = $w->keepalive ($bool) 510=item $previous_state = $w->keepalive ($bool)
398 511
399Normally, C<EV::loop> will return when there are no active watchers 512Normally, C<EV::run> will return when there are no active watchers
400(which is a "deadlock" because no progress can be made anymore). This is 513(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), 514convenient 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 515call C<EV::run> once and when it returns you know that all your jobs are
403finished (or they forgot to register some watchers for their task :). 516finished (or they forgot to register some watchers for their task :).
404 517
405Sometimes, however, this gets in your way, for example when the module 518Sometimes, 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 519that calls C<EV::run> (usually the main program) is not the same module
407as a long-living watcher (for example a DNS client module written by 520as a long-living watcher (for example a DNS client module written by
408somebody else even). Then you might want any outstanding requests to be 521somebody else even). Then you might want any outstanding requests to be
409handled, but you would not want to keep C<EV::loop> from returning just 522handled, but you would not want to keep C<EV::run> from returning just
410because you happen to have this long-running UDP port watcher. 523because you happen to have this long-running UDP port watcher.
411 524
412In this case you can clear the keepalive status, which means that even 525In 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. 526though your watcher is active, it won't keep C<EV::run> from returning.
414 527
415The initial value for keepalive is true (enabled), and you cna change it 528The initial value for keepalive is true (enabled), and you can change it
416any time. 529any time.
417 530
418Example: Register an I/O watcher for some UDP socket but do not keep the 531Example: Register an I/O watcher for some UDP socket but do not keep the
419event loop from running just because of that watcher. 532event loop from running just because of that watcher.
420 533
… …
485 598
486=item $w = $loop->timer ($after, $repeat, $callback) 599=item $w = $loop->timer ($after, $repeat, $callback)
487 600
488=item $w = $loop->timer_ns ($after, $repeat, $callback) 601=item $w = $loop->timer_ns ($after, $repeat, $callback)
489 602
490Calls the callback after C<$after> seconds (which may be fractional). If 603Calls the callback after C<$after> seconds (which may be fractional or
491C<$repeat> is non-zero, the timer will be restarted (with the $repeat 604negative). If C<$repeat> is non-zero, the timer will be restarted (with
492value as $after) after the callback returns. 605the $repeat value as $after) after the callback returns.
493 606
494This means that the callback would be called roughly after C<$after> 607This means that the callback would be called roughly after C<$after>
495seconds, and then every C<$repeat> seconds. The timer does his best not 608seconds, and then every C<$repeat> seconds. The timer does his best not
496to drift, but it will not invoke the timer more often then once per event 609to drift, but it will not invoke the timer more often then once per event
497loop iteration, and might drift in other cases. If that isn't acceptable, 610loop iteration, and might drift in other cases. If that isn't acceptable,
… …
501in front of the machine while the timer is running and changes the system 614in front of the machine while the timer is running and changes the system
502clock, the timer will nevertheless run (roughly) the same time. 615clock, the timer will nevertheless run (roughly) the same time.
503 616
504The C<timer_ns> variant doesn't start (activate) the newly created watcher. 617The C<timer_ns> variant doesn't start (activate) the newly created watcher.
505 618
506=item $w->set ($after, $repeat) 619=item $w->set ($after, $repeat = 0)
507 620
508Reconfigures the watcher, see the constructor above for details. Can be called at 621Reconfigures the watcher, see the constructor above for details. Can be called at
509any time. 622any time.
510 623
511=item $w->again 624=item $w->again
625
626=item $w->again ($repeat)
512 627
513Similar to the C<start> method, but has special semantics for repeating timers: 628Similar to the C<start> method, but has special semantics for repeating timers:
514 629
515If the timer is active and non-repeating, it will be stopped. 630If the timer is active and non-repeating, it will be stopped.
516 631
… …
523 638
524This behaviour is useful when you have a timeout for some IO 639This behaviour is useful when you have a timeout for some IO
525operation. You create a timer object with the same value for C<$after> and 640operation. You create a timer object with the same value for C<$after> and
526C<$repeat>, and then, in the read/write watcher, run the C<again> method 641C<$repeat>, and then, in the read/write watcher, run the C<again> method
527on the timeout. 642on the timeout.
643
644If called with a C<$repeat> argument, then it uses this a timer repeat
645value.
646
647=item $after = $w->remaining
648
649Calculates and returns the remaining time till the timer will fire.
650
651=item $repeat = $w->repeat
652
653=item $old_repeat = $w->repeat ($new_repeat)
654
655Returns the current value of the repeat attribute and optionally sets a
656new one. Setting the new one will not restart the watcher - if the watcher
657is active, the new repeat value is used whenever it expires next.
528 658
529=back 659=back
530 660
531 661
532=head3 PERIODIC WATCHERS - to cron or not to cron? 662=head3 PERIODIC WATCHERS - to cron or not to cron?
… …
560surpasses this time. 690surpasses this time.
561 691
562=item * repeating interval timer ($interval > 0, $reschedule_cb = 0) 692=item * repeating interval timer ($interval > 0, $reschedule_cb = 0)
563 693
564In this mode the watcher will always be scheduled to time out at the 694In this mode the watcher will always be scheduled to time out at the
565next C<$at + N * $interval> time (for some integer N) and then repeat, 695next C<$at + N * $interval> time (for the lowest integer N) and then repeat,
566regardless of any time jumps. 696regardless of any time jumps. Note that, since C<N> can be negative, the
697first trigger can happen before C<$at>.
567 698
568This can be used to create timers that do not drift with respect to system 699This can be used to create timers that do not drift with respect to system
569time: 700time:
570 701
571 my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" }; 702 my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" };
572 703
573That doesn't mean there will always be 3600 seconds in between triggers, 704That doesn't mean there will always be 3600 seconds in between triggers,
574but only that the the clalback will be called when the system time shows a 705but only that the the callback will be called when the system time shows a
575full hour (UTC). 706full hour (UTC).
576 707
577Another way to think about it (for the mathematically inclined) is that 708Another way to think about it (for the mathematically inclined) is that
578EV::periodic will try to run the callback in this mode at the next 709EV::periodic will try to run the callback in this mode at the next
579possible time where C<$time = $at (mod $interval)>, regardless of any time 710possible time where C<$time = $at (mod $interval)>, regardless of any time
… …
587time as second argument. 718time as second argument.
588 719
589I<This callback MUST NOT stop or destroy this or any other periodic 720I<This callback MUST NOT stop or destroy this or any other periodic
590watcher, ever, and MUST NOT call any event loop functions or methods>. If 721watcher, ever, and MUST NOT call any event loop functions or methods>. If
591you need to stop it, return 1e30 and stop it afterwards. You may create 722you need to stop it, return 1e30 and stop it afterwards. You may create
592and start a C<EV::prepare> watcher for this task. 723and start an C<EV::prepare> watcher for this task.
593 724
594It must return the next time to trigger, based on the passed time value 725It must return the next time to trigger, based on the passed time value
595(that is, the lowest time value larger than or equal to to the second 726(that is, the lowest time value larger than or equal to to the second
596argument). It will usually be called just before the callback will be 727argument). It will usually be called just before the callback will be
597triggered, but might be called at other times, too. 728triggered, but might be called at other times, too.
598 729
599This can be used to create very complex timers, such as a timer that 730This can be used to create very complex timers, such as a timer that
600triggers on each midnight, local time (actually 24 hours after the last 731triggers on each midnight, local time (actually one day after the last
601midnight, to keep the example simple. If you know a way to do it correctly 732midnight, to keep the example simple):
602in about the same space (without requiring elaborate modules), drop me a
603note :):
604 733
605 my $daily = EV::periodic 0, 0, sub { 734 my $daily = EV::periodic 0, 0, sub {
606 my ($w, $now) = @_; 735 my ($w, $now) = @_;
607 736
608 use Time::Local (); 737 use Time::Local ();
609 my (undef, undef, undef, $d, $m, $y) = localtime $now; 738 my (undef, undef, undef, $d, $m, $y) = localtime $now;
610 86400 + Time::Local::timelocal 0, 0, 0, $d, $m, $y 739 Time::Local::timelocal_nocheck 0, 0, 0, $d + 1, $m, $y
611 }, sub { 740 }, sub {
612 print "it's midnight or likely shortly after, now\n"; 741 print "it's midnight or likely shortly after, now\n";
613 }; 742 };
614 743
615=back 744=back
… …
627 756
628=item $time = $w->at 757=item $time = $w->at
629 758
630Return the time that the watcher is expected to trigger next. 759Return the time that the watcher is expected to trigger next.
631 760
761=item $offset = $w->offset
762
763=item $old_offset = $w->offset ($new_offset)
764
765Returns the current value of the offset attribute and optionally sets a
766new one. Setting the new one will not restart the watcher - if the watcher
767is active, the new offset value is used whenever it expires next.
768
769=item $interval = $w->interval
770
771=item $old_interval = $w->interval ($new_interval)
772
773See above, for the interval attribute.
774
775=item $reschedule_cb = $w->reschedule_cb
776
777=item $old_reschedule_cb = $w->reschedule_cb ($new_reschedule_cb)
778
779See above, for the reschedule callback.
780
632=back 781=back
633 782
634 783
635=head3 SIGNAL WATCHERS - signal me when a signal gets signalled! 784=head3 SIGNAL WATCHERS - signal me when a signal gets signalled!
636 785
637=over 4 786=over 4
638 787
639=item $w = EV::signal $signal, $callback 788=item $w = EV::signal $signal, $callback
640 789
641=item $w = EV::signal_ns $signal, $callback 790=item $w = EV::signal_ns $signal, $callback
791
792=item $w = $loop->signal ($signal, $callback)
793
794=item $w = $loop->signal_ns ($signal, $callback)
642 795
643Call the callback when $signal is received (the signal can be specified by 796Call the callback when $signal is received (the signal can be specified by
644number or by name, just as with C<kill> or C<%SIG>). 797number or by name, just as with C<kill> or C<%SIG>).
798
799Only one event loop can grab a given signal - attempting to grab the same
800signal from two EV loops will crash the program immediately or cause data
801corruption.
645 802
646EV will grab the signal for the process (the kernel only allows one 803EV 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, 804component 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 805and removes it again when you stop it. Perl does the same when you
649add/remove callbacks to C<%SIG>, so watch out. 806add/remove callbacks to C<%SIG>, so watch out.
… …
716=item $pid = $w->rpid 873=item $pid = $w->rpid
717 874
718Return the pid of the awaited child (useful when you have installed a 875Return the pid of the awaited child (useful when you have installed a
719watcher for all pids). 876watcher for all pids).
720 877
878=item EV::Child::reinit [EXPERIMENTAL]
879
880Internally, libev installs a signal handler for C<SIGCHLD>. Unfortunately,
881a lot of Perl code does soemthing like C<< local $SIG{CHLD} >>, which,
882unfortunately, is broken and will not restore the signal handler.
883
884If this has happened, you can call this function to stop/rrestart the
885internal libev watcher, which will reset the signal handler.
886
887Note that this is an experimental function, whose interface might change.
888
721=back 889=back
722 890
723 891
724=head3 STAT WATCHERS - did the file attributes just change? 892=head3 STAT WATCHERS - did the file attributes just change?
725 893
… …
874=item $w = $loop->check_ns ($callback) 1042=item $w = $loop->check_ns ($callback)
875 1043
876Call the callback just after the process wakes up again (after it has 1044Call the callback just after the process wakes up again (after it has
877gathered events), but before any other callbacks have been invoked. 1045gathered events), but before any other callbacks have been invoked.
878 1046
879This is used to integrate other event-based software into the EV 1047This can be used to integrate other event-based software into the EV
880mainloop: You register a prepare callback and in there, you create io and 1048mainloop: You register a prepare callback and in there, you create io and
881timer watchers as required by the other software. Here is a real-world 1049timer watchers as required by the other software. Here is a real-world
882example of integrating Net::SNMP (with some details left out): 1050example of integrating Net::SNMP (with some details left out):
883 1051
884 our @snmp_watcher; 1052 our @snmp_watcher;
… …
914 # make the dispatcher handle any new stuff 1082 # make the dispatcher handle any new stuff
915 ... not shown 1083 ... not shown
916 }; 1084 };
917 1085
918The callbacks of the created watchers will not be called as the watchers 1086The callbacks of the created watchers will not be called as the watchers
919are destroyed before this cna happen (remember EV::check gets called 1087are destroyed before this can happen (remember EV::check gets called
920first). 1088first).
921 1089
922The C<check_ns> variant doesn't start (activate) the newly created watcher. 1090The C<check_ns> variant doesn't start (activate) the newly created watcher.
1091
1092=item EV::CHECK constant issues
1093
1094Like all other watcher types, there is a bitmask constant for use in
1095C<$revents> and other places. The C<EV::CHECK> is special as it has
1096the same name as the C<CHECK> sub called by Perl. This doesn't cause
1097big issues on newer perls (beginning with 5.8.9), but it means thatthe
1098constant must be I<inlined>, i.e. runtime calls will not work. That means
1099that as long as you always C<use EV> and then C<EV::CHECK> you are on the
1100safe side.
923 1101
924=back 1102=back
925 1103
926 1104
927=head3 FORK WATCHERS - the audacity to resume the event loop after a fork 1105=head3 FORK WATCHERS - the audacity to resume the event loop after a fork
… …
955loop, other types of watchers might be handled in a delayed or incorrect 1133loop, other types of watchers might be handled in a delayed or incorrect
956fashion and must not be used). 1134fashion and must not be used).
957 1135
958See the libev documentation at 1136See the libev documentation at
959L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_> 1137L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_>
960for more details. 1138(locally installed as F<EV::libev>) for more details.
961 1139
962In short, this watcher is most useful on BSD systems without working 1140In short, this watcher is most useful on BSD systems without working
963kqueue to still be able to handle a large number of sockets: 1141kqueue to still be able to handle a large number of sockets:
964 1142
965 my $socket_loop; 1143 my $socket_loop;
… …
995 1173
996=back 1174=back
997 1175
998=head3 ASYNC WATCHERS - how to wake up another event loop 1176=head3 ASYNC WATCHERS - how to wake up another event loop
999 1177
1000Async watchers are provided by EV, but have little use in perl directly, as perl 1178Async watchers are provided by EV, but have little use in perl directly,
1001neither supports threads nor direct access to signal handlers or other 1179as perl neither supports threads running in parallel nor direct access to
1002contexts where they could be of value. 1180signal handlers or other contexts where they could be of value.
1003 1181
1004It is, however, possible to use them from the XS level. 1182It is, however, possible to use them from the XS level.
1005 1183
1006Please see the libev documentation for further details. 1184Please see the libev documentation for further details.
1007 1185
… …
1009 1187
1010=item $w = EV::async $callback 1188=item $w = EV::async $callback
1011 1189
1012=item $w = EV::async_ns $callback 1190=item $w = EV::async_ns $callback
1013 1191
1192=item $w = $loop->async ($callback)
1193
1194=item $w = $loop->async_ns ($callback)
1195
1014=item $w->send 1196=item $w->send
1015 1197
1016=item $bool = $w->async_pending 1198=item $bool = $w->async_pending
1017 1199
1018=back 1200=back
1201
1202=head3 CLEANUP WATCHERS - how to clean up when the event loop goes away
1203
1204Cleanup watchers are not supported on the Perl level, they can only be
1205used via XS currently.
1019 1206
1020 1207
1021=head1 PERL SIGNALS 1208=head1 PERL SIGNALS
1022 1209
1023While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour 1210While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour
… …
1035 my $async_check = EV::check sub { }; 1222 my $async_check = EV::check sub { };
1036 1223
1037This ensures that perl gets into control for a short time to handle any 1224This ensures that perl gets into control for a short time to handle any
1038pending signals, and also ensures (slightly) slower overall operation. 1225pending signals, and also ensures (slightly) slower overall operation.
1039 1226
1040=head1 THREADS 1227=head1 ITHREADS
1041 1228
1042Threads are not supported by this module in any way. Perl pseudo-threads 1229Ithreads 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 1230is evil stuff and must die. Real threads as provided by Coro are fully
1044on thread support for it. 1231supported (and enhanced support is available via L<Coro::EV>).
1045 1232
1046=head1 FORK 1233=head1 FORK
1047 1234
1048Most of the "improved" event delivering mechanisms of modern operating 1235Most of the "improved" event delivering mechanisms of modern operating
1049systems have quite a few problems with fork(2) (to put it bluntly: it is 1236systems have quite a few problems with fork(2) (to put it bluntly: it is
… …
1071 1258
10721; 12591;
1073 1260
1074=head1 SEE ALSO 1261=head1 SEE ALSO
1075 1262
1263L<EV::MakeMaker> - MakeMaker interface to XS API, L<EV::ADNS>
1076L<EV::ADNS> (asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as 1264(asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as event
1077event loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient 1265loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient thread
1078coroutines with EV), L<Net::SNMP::EV> (asynchronous SNMP), L<AnyEvent> for 1266integration), L<Net::SNMP::EV> (asynchronous SNMP), L<AnyEvent> for
1079event-loop agnostic and portable event driven programming. 1267event-loop agnostic and portable event driven programming.
1080 1268
1081=head1 AUTHOR 1269=head1 AUTHOR
1082 1270
1083 Marc Lehmann <schmorp@schmorp.de> 1271 Marc Lehmann <schmorp@schmorp.de>

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