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Revision 1.41 by root, Fri Mar 1 11:20:07 2013 UTC vs.
Revision 1.46 by root, Mon Jun 24 22:33:39 2019 UTC

46 my ($w, $revents) = @_; 46 my ($w, $revents) = @_;
47 warn $w->path, " has changed somehow.\n"; 47 warn $w->path, " has changed somehow.\n";
48 }; 48 };
49 49
50 # MAINLOOP 50 # MAINLOOP
51 EV::run; # loop until EV::unloop is called or all watchers stop 51 EV::run; # loop until EV::break is called or all watchers stop
52 EV::run EV::RUN_ONCE; # block until at least one event could be handled 52 EV::run EV::RUN_ONCE; # block until at least one event could be handled
53 EV::run EV::RUN_NOWAIT; # try to handle same events, but do not block 53 EV::run EV::RUN_NOWAIT; # try to handle same events, but do not block
54 54
55BEFORE YOU START USING THIS MODULE 55BEFORE YOU START USING THIS MODULE
56 If you only need timer, I/O, signal, child and idle watchers and not the 56 If you only need timer, I/O, signal, child and idle watchers and not the
195 195
196 EV::now_update 196 EV::now_update
197 $loop->now_update 197 $loop->now_update
198 Establishes the current time by querying the kernel, updating the 198 Establishes the current time by querying the kernel, updating the
199 time returned by "EV::now" in the progress. This is a costly 199 time returned by "EV::now" in the progress. This is a costly
200 operation and is usually done automatically within "EV::loop". 200 operation and is usually done automatically within "EV::run".
201 201
202 This function is rarely useful, but when some event callback runs 202 This function is rarely useful, but when some event callback runs
203 for a very long time without entering the event loop, updating 203 for a very long time without entering the event loop, updating
204 libev's idea of the current time is a good idea. 204 libev's idea of the current time is a good idea.
205 205
236 (EV::BACKEND_SELECT or EV::BACKEND_EPOLL). 236 (EV::BACKEND_SELECT or EV::BACKEND_EPOLL).
237 237
238 $active = EV::run [$flags] 238 $active = EV::run [$flags]
239 $active = $loop->run ([$flags]) 239 $active = $loop->run ([$flags])
240 Begin checking for events and calling callbacks. It returns when a 240 Begin checking for events and calling callbacks. It returns when a
241 callback calls EV::unloop or the flasg are nonzero (in which case 241 callback calls EV::break or the flags are nonzero (in which case the
242 the return value is true) or when there are no active watchers which 242 return value is true) or when there are no active watchers which
243 reference the loop (keepalive is true), in which case the return 243 reference the loop (keepalive is true), in which case the return
244 value will be false. The returnv alue can generally be interpreted 244 value will be false. The return value can generally be interpreted
245 as "if true, there is more work left to do". 245 as "if true, there is more work left to do".
246 246
247 The $flags argument can be one of the following: 247 The $flags argument can be one of the following:
248 248
249 0 as above 249 0 as above
251 EV::RUN_NOWAIT do not block at all (fetch/handle events but do not wait) 251 EV::RUN_NOWAIT do not block at all (fetch/handle events but do not wait)
252 252
253 EV::break [$how] 253 EV::break [$how]
254 $loop->break ([$how]) 254 $loop->break ([$how])
255 When called with no arguments or an argument of EV::BREAK_ONE, makes 255 When called with no arguments or an argument of EV::BREAK_ONE, makes
256 the innermost call to EV::loop return. 256 the innermost call to EV::run return.
257 257
258 When called with an argument of EV::BREAK_ALL, all calls to EV::loop 258 When called with an argument of EV::BREAK_ALL, all calls to EV::run
259 will return as fast as possible. 259 will return as fast as possible.
260 260
261 When called with an argument of EV::BREAK_CANCEL, any pending break 261 When called with an argument of EV::BREAK_CANCEL, any pending break
262 will be cancelled. 262 will be cancelled.
263 263
276 "EV::READ | EV::WRITE", indicating the type of I/O event you want to 276 "EV::READ | EV::WRITE", indicating the type of I/O event you want to
277 wait for. If you do not want to wait for some I/O event, specify 277 wait for. If you do not want to wait for some I/O event, specify
278 "undef" for $fh_or_undef and 0 for $events). 278 "undef" for $fh_or_undef and 0 for $events).
279 279
280 If timeout is "undef" or negative, then there will be no timeout. 280 If timeout is "undef" or negative, then there will be no timeout.
281 Otherwise a EV::timer with this value will be started. 281 Otherwise an "EV::timer" with this value will be started.
282 282
283 When an error occurs or either the timeout or I/O watcher triggers, 283 When an error occurs or either the timeout or I/O watcher triggers,
284 then the callback will be called with the received event set (in 284 then the callback will be called with the received event set (in
285 general you can expect it to be a combination of "EV::ERROR", 285 general you can expect it to be a combination of "EV::ERROR",
286 "EV::READ", "EV::WRITE" and "EV::TIMER"). 286 "EV::READ", "EV::WRITE" and "EV::TIMER").
414 If the watcher is pending, this function clears its pending status 414 If the watcher is pending, this function clears its pending status
415 and returns its $revents bitset (as if its callback was invoked). If 415 and returns its $revents bitset (as if its callback was invoked). If
416 the watcher isn't pending it does nothing and returns 0. 416 the watcher isn't pending it does nothing and returns 0.
417 417
418 $previous_state = $w->keepalive ($bool) 418 $previous_state = $w->keepalive ($bool)
419 Normally, "EV::loop" will return when there are no active watchers 419 Normally, "EV::run" will return when there are no active watchers
420 (which is a "deadlock" because no progress can be made anymore). 420 (which is a "deadlock" because no progress can be made anymore).
421 This is convenient because it allows you to start your watchers (and 421 This is convenient because it allows you to start your watchers (and
422 your jobs), call "EV::loop" once and when it returns you know that 422 your jobs), call "EV::run" once and when it returns you know that
423 all your jobs are finished (or they forgot to register some watchers 423 all your jobs are finished (or they forgot to register some watchers
424 for their task :). 424 for their task :).
425 425
426 Sometimes, however, this gets in your way, for example when the 426 Sometimes, however, this gets in your way, for example when the
427 module that calls "EV::loop" (usually the main program) is not the 427 module that calls "EV::run" (usually the main program) is not the
428 same module as a long-living watcher (for example a DNS client 428 same module as a long-living watcher (for example a DNS client
429 module written by somebody else even). Then you might want any 429 module written by somebody else even). Then you might want any
430 outstanding requests to be handled, but you would not want to keep 430 outstanding requests to be handled, but you would not want to keep
431 "EV::loop" from returning just because you happen to have this 431 "EV::run" from returning just because you happen to have this
432 long-running UDP port watcher. 432 long-running UDP port watcher.
433 433
434 In this case you can clear the keepalive status, which means that 434 In this case you can clear the keepalive status, which means that
435 even though your watcher is active, it won't keep "EV::loop" from 435 even though your watcher is active, it won't keep "EV::run" from
436 returning. 436 returning.
437 437
438 The initial value for keepalive is true (enabled), and you can 438 The initial value for keepalive is true (enabled), and you can
439 change it any time. 439 change it any time.
440 440
482 TIMER WATCHERS - relative and optionally repeating timeouts 482 TIMER WATCHERS - relative and optionally repeating timeouts
483 $w = EV::timer $after, $repeat, $callback 483 $w = EV::timer $after, $repeat, $callback
484 $w = EV::timer_ns $after, $repeat, $callback 484 $w = EV::timer_ns $after, $repeat, $callback
485 $w = $loop->timer ($after, $repeat, $callback) 485 $w = $loop->timer ($after, $repeat, $callback)
486 $w = $loop->timer_ns ($after, $repeat, $callback) 486 $w = $loop->timer_ns ($after, $repeat, $callback)
487 Calls the callback after $after seconds (which may be fractional). 487 Calls the callback after $after seconds (which may be fractional or
488 If $repeat is non-zero, the timer will be restarted (with the 488 negative). If $repeat is non-zero, the timer will be restarted (with
489 $repeat value as $after) after the callback returns. 489 the $repeat value as $after) after the callback returns.
490 490
491 This means that the callback would be called roughly after $after 491 This means that the callback would be called roughly after $after
492 seconds, and then every $repeat seconds. The timer does his best not 492 seconds, and then every $repeat seconds. The timer does his best not
493 to drift, but it will not invoke the timer more often then once per 493 to drift, but it will not invoke the timer more often then once per
494 event loop iteration, and might drift in other cases. If that isn't 494 event loop iteration, and might drift in other cases. If that isn't
501 the same time. 501 the same time.
502 502
503 The "timer_ns" variant doesn't start (activate) the newly created 503 The "timer_ns" variant doesn't start (activate) the newly created
504 watcher. 504 watcher.
505 505
506 $w->set ($after, $repeat) 506 $w->set ($after, $repeat = 0)
507 Reconfigures the watcher, see the constructor above for details. Can 507 Reconfigures the watcher, see the constructor above for details. Can
508 be called at any time. 508 be called at any time.
509 509
510 $w->again 510 $w->again
511 $w->again ($repeat)
511 Similar to the "start" method, but has special semantics for 512 Similar to the "start" method, but has special semantics for
512 repeating timers: 513 repeating timers:
513 514
514 If the timer is active and non-repeating, it will be stopped. 515 If the timer is active and non-repeating, it will be stopped.
515 516
523 524
524 This behaviour is useful when you have a timeout for some IO 525 This behaviour is useful when you have a timeout for some IO
525 operation. You create a timer object with the same value for $after 526 operation. You create a timer object with the same value for $after
526 and $repeat, and then, in the read/write watcher, run the "again" 527 and $repeat, and then, in the read/write watcher, run the "again"
527 method on the timeout. 528 method on the timeout.
529
530 If called with a $repeat argument, then it uses this a timer repeat
531 value.
532
533 $after = $w->remaining
534 Calculates and returns the remaining time till the timer will fire.
528 535
529 PERIODIC WATCHERS - to cron or not to cron? 536 PERIODIC WATCHERS - to cron or not to cron?
530 $w = EV::periodic $at, $interval, $reschedule_cb, $callback 537 $w = EV::periodic $at, $interval, $reschedule_cb, $callback
531 $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback 538 $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
532 $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback) 539 $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback)
549 system time reaches or surpasses this time. 556 system time reaches or surpasses this time.
550 557
551 * repeating interval timer ($interval > 0, $reschedule_cb = 0) 558 * repeating interval timer ($interval > 0, $reschedule_cb = 0)
552 559
553 In this mode the watcher will always be scheduled to time out at 560 In this mode the watcher will always be scheduled to time out at
554 the next "$at + N * $interval" time (for some integer N) and 561 the next "$at + N * $interval" time (for the lowest integer N)
555 then repeat, regardless of any time jumps. 562 and then repeat, regardless of any time jumps. Note that, since
563 "N" can be negative, the first trigger can happen before $at.
556 564
557 This can be used to create timers that do not drift with respect 565 This can be used to create timers that do not drift with respect
558 to system time: 566 to system time:
559 567
560 my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" }; 568 my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" };
561 569
562 That doesn't mean there will always be 3600 seconds in between 570 That doesn't mean there will always be 3600 seconds in between
563 triggers, but only that the the clalback will be called when the 571 triggers, but only that the the callback will be called when the
564 system time shows a full hour (UTC). 572 system time shows a full hour (UTC).
565 573
566 Another way to think about it (for the mathematically inclined) 574 Another way to think about it (for the mathematically inclined)
567 is that EV::periodic will try to run the callback in this mode 575 is that EV::periodic will try to run the callback in this mode
568 at the next possible time where "$time = $at (mod $interval)", 576 at the next possible time where "$time = $at (mod $interval)",
576 first, and the current time as second argument. 584 first, and the current time as second argument.
577 585
578 *This callback MUST NOT stop or destroy this or any other 586 *This callback MUST NOT stop or destroy this or any other
579 periodic watcher, ever, and MUST NOT call any event loop 587 periodic watcher, ever, and MUST NOT call any event loop
580 functions or methods*. If you need to stop it, return 1e30 and 588 functions or methods*. If you need to stop it, return 1e30 and
581 stop it afterwards. You may create and start a "EV::prepare" 589 stop it afterwards. You may create and start an "EV::prepare"
582 watcher for this task. 590 watcher for this task.
583 591
584 It must return the next time to trigger, based on the passed 592 It must return the next time to trigger, based on the passed
585 time value (that is, the lowest time value larger than or equal 593 time value (that is, the lowest time value larger than or equal
586 to to the second argument). It will usually be called just 594 to to the second argument). It will usually be called just
587 before the callback will be triggered, but might be called at 595 before the callback will be triggered, but might be called at
588 other times, too. 596 other times, too.
589 597
590 This can be used to create very complex timers, such as a timer 598 This can be used to create very complex timers, such as a timer
591 that triggers on each midnight, local time (actually 24 hours 599 that triggers on each midnight, local time (actually one day
592 after the last midnight, to keep the example simple. If you know 600 after the last midnight, to keep the example simple):
593 a way to do it correctly in about the same space (without
594 requiring elaborate modules), drop me a note :):
595 601
596 my $daily = EV::periodic 0, 0, sub { 602 my $daily = EV::periodic 0, 0, sub {
597 my ($w, $now) = @_; 603 my ($w, $now) = @_;
598 604
599 use Time::Local (); 605 use Time::Local ();
600 my (undef, undef, undef, $d, $m, $y) = localtime $now; 606 my (undef, undef, undef, $d, $m, $y) = localtime $now;
601 86400 + Time::Local::timelocal 0, 0, 0, $d, $m, $y 607 Time::Local::timelocal_nocheck 0, 0, 0, $d + 1, $m, $y
602 }, sub { 608 }, sub {
603 print "it's midnight or likely shortly after, now\n"; 609 print "it's midnight or likely shortly after, now\n";
604 }; 610 };
605 611
606 The "periodic_ns" variant doesn't start (activate) the newly created 612 The "periodic_ns" variant doesn't start (activate) the newly created

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