| … | |
… | |
| 16 | warn "is called roughly every 2s (repeat = 1)"; |
16 | warn "is called roughly every 2s (repeat = 1)"; |
| 17 | }; |
17 | }; |
| 18 | |
18 | |
| 19 | undef $w; # destroy event watcher again |
19 | undef $w; # destroy event watcher again |
| 20 | |
20 | |
| 21 | my $w = EV::periodic 0, 60, sub { |
21 | my $w = EV::periodic 0, 60, 0, sub { |
| 22 | warn "is called every minute, on the minute, exactly"; |
22 | warn "is called every minute, on the minute, exactly"; |
| 23 | }; |
23 | }; |
| 24 | |
24 | |
| 25 | # IO |
25 | # IO |
| 26 | |
26 | |
| … | |
… | |
| 186 | |
186 | |
| 187 | =item $bool = $w->is_active |
187 | =item $bool = $w->is_active |
| 188 | |
188 | |
| 189 | Returns true if the watcher is active, false otherwise. |
189 | Returns true if the watcher is active, false otherwise. |
| 190 | |
190 | |
|
|
191 | =item $current_data = $w->data |
|
|
192 | |
|
|
193 | =item $old_data = $w->data ($new_data) |
|
|
194 | |
|
|
195 | Queries a freely usable data scalar on the watcher and optionally changes |
|
|
196 | it. This is a way to associate custom data with a watcher: |
|
|
197 | |
|
|
198 | my $w = EV::timer 60, 0, sub { |
|
|
199 | warn $_[0]->data; |
|
|
200 | }; |
|
|
201 | $w->data ("print me!"); |
|
|
202 | |
| 191 | =item $current_cb = $w->cb |
203 | =item $current_cb = $w->cb |
| 192 | |
204 | |
| 193 | =item $old_cb = $w->cb ($new_cb) |
205 | =item $old_cb = $w->cb ($new_cb) |
| 194 | |
206 | |
| 195 | Queries the callback on the watcher and optionally changes it. You can do |
207 | Queries the callback on the watcher and optionally changes it. You can do |
| … | |
… | |
| 285 | operation. You create a timer object with the same value for C<$after> and |
297 | operation. You create a timer object with the same value for C<$after> and |
| 286 | C<$repeat>, and then, in the read/write watcher, run the C<again> method |
298 | C<$repeat>, and then, in the read/write watcher, run the C<again> method |
| 287 | on the timeout. |
299 | on the timeout. |
| 288 | |
300 | |
| 289 | |
301 | |
| 290 | =item $w = EV::periodic $at, $interval, $callback |
302 | =item $w = EV::periodic $at, $interval, $reschedule_cb, $callback |
| 291 | |
303 | |
| 292 | =item $w = EV::periodic_ns $at, $interval, $callback |
304 | =item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback |
| 293 | |
305 | |
| 294 | Similar to EV::timer, but the time is given as an absolute point in time |
306 | Similar to EV::timer, but is not based on relative timeouts but on |
| 295 | (C<$at>), plus an optional C<$interval>. |
307 | absolute times. Apart from creating "simple" timers that trigger "at" the |
|
|
308 | specified time, it can also be used for non-drifting absolute timers and |
|
|
309 | more complex, cron-like, setups that are not adversely affected by time |
|
|
310 | jumps (i.e. when the system clock is changed by explicit date -s or other |
|
|
311 | means such as ntpd). It is also the most complex watcher type in EV. |
| 296 | |
312 | |
| 297 | If the C<$interval> is zero, then the callback will be called at the time |
313 | It has three distinct "modes": |
| 298 | C<$at> if that is in the future, or as soon as possible if it is in the |
|
|
| 299 | past. It will not automatically repeat. |
|
|
| 300 | |
314 | |
| 301 | If the C<$interval> is nonzero, then the watcher will always be scheduled |
315 | =over 4 |
| 302 | to time out at the next C<$at + N * $interval> time. |
|
|
| 303 | |
316 | |
| 304 | This can be used to schedule a callback to run at very regular intervals, |
317 | =item * absolute timer ($interval = $reschedule_cb = 0) |
| 305 | as long as the processing time is less then the interval (otherwise |
318 | |
| 306 | obviously events will be skipped). |
319 | This time simply fires at the wallclock time C<$at> and doesn't repeat. It |
|
|
320 | will not adjust when a time jump occurs, that is, if it is to be run |
|
|
321 | at January 1st 2011 then it will run when the system time reaches or |
|
|
322 | surpasses this time. |
|
|
323 | |
|
|
324 | =item * non-repeating interval timer ($interval > 0, $reschedule_cb = 0) |
|
|
325 | |
|
|
326 | In this mode the watcher will always be scheduled to time out at the |
|
|
327 | next C<$at + N * $interval> time (for some integer N) and then repeat, |
|
|
328 | regardless of any time jumps. |
|
|
329 | |
|
|
330 | This can be used to create timers that do not drift with respect to system |
|
|
331 | time: |
|
|
332 | |
|
|
333 | my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" }; |
|
|
334 | |
|
|
335 | That doesn't mean there will always be 3600 seconds in between triggers, |
|
|
336 | but only that the the clalback will be called when the system time shows a |
|
|
337 | full hour (UTC). |
| 307 | |
338 | |
| 308 | Another way to think about it (for the mathematically inclined) is that |
339 | Another way to think about it (for the mathematically inclined) is that |
| 309 | EV::periodic will try to run the callback at the next possible time where |
340 | EV::periodic will try to run the callback in this mode at the next |
| 310 | C<$time = $at (mod $interval)>, regardless of any time jumps. |
341 | possible time where C<$time = $at (mod $interval)>, regardless of any time |
|
|
342 | jumps. |
| 311 | |
343 | |
| 312 | This periodic timer is based on "wallclock time", that is, if the clock |
344 | =item * manual reschedule mode ($reschedule_cb = coderef) |
| 313 | changes (C<ntp>, C<date -s> etc.), then the timer will nevertheless run at |
345 | |
| 314 | the specified time. This means it will never drift (it might jitter, but |
346 | In this mode $interval and $at are both being ignored. Instead, each time |
| 315 | it will not drift). |
347 | the periodic watcher gets scheduled, the first callback ($reschedule_cb) |
|
|
348 | will be called with the watcher as first, and the current time as second |
|
|
349 | argument. |
|
|
350 | |
|
|
351 | I<This callback MUST NOT stop or destroy the event watcher, ever.> |
|
|
352 | |
|
|
353 | It must return the next time to trigger, based on the passed time value |
|
|
354 | (that is, the lowest time value larger than to the second argument). It |
|
|
355 | will usually be called just before the callback will be triggered, but |
|
|
356 | might be called at other times, too. |
|
|
357 | |
|
|
358 | This can be used to create very complex timers, such as a timer that |
|
|
359 | triggers on each midnight, local time (actually 24 hours after the last |
|
|
360 | midnight, to keep the example simple. If you know a way to do it correctly |
|
|
361 | in about the same space (without requiring elaborate modules), drop me a |
|
|
362 | note :): |
|
|
363 | |
|
|
364 | my $daily = EV::periodic 0, 0, sub { |
|
|
365 | my ($w, $now) = @_; |
|
|
366 | |
|
|
367 | use Time::Local (); |
|
|
368 | my (undef, undef, undef, $d, $m, $y) = localtime $now; |
|
|
369 | 86400 + Time::Local::timelocal 0, 0, 0, $d, $m, $y |
|
|
370 | }, sub { |
|
|
371 | print "it's midnight or likely shortly after, now\n"; |
|
|
372 | }; |
|
|
373 | |
|
|
374 | =back |
| 316 | |
375 | |
| 317 | The C<periodic_ns> variant doesn't start (activate) the newly created watcher. |
376 | The C<periodic_ns> variant doesn't start (activate) the newly created watcher. |
| 318 | |
377 | |
| 319 | =item $w->set ($at, $interval) |
378 | =item $w->set ($at, $interval, $reschedule_cb) |
| 320 | |
379 | |
| 321 | Reconfigures the watcher, see the constructor above for details. Can be at |
380 | Reconfigures the watcher, see the constructor above for details. Can be at |
| 322 | any time. |
381 | any time. |
|
|
382 | |
|
|
383 | =item $w->again |
|
|
384 | |
|
|
385 | Simply stops and starts the watcher again. |
| 323 | |
386 | |
| 324 | |
387 | |
| 325 | =item $w = EV::signal $signal, $callback |
388 | =item $w = EV::signal $signal, $callback |
| 326 | |
389 | |
| 327 | =item $w = EV::signal_ns $signal, $callback |
390 | =item $w = EV::signal_ns $signal, $callback |
