… | |
… | |
15 | warn "is called roughly every 2s (repeat = 1)"; |
15 | warn "is called roughly every 2s (repeat = 1)"; |
16 | }; |
16 | }; |
17 | |
17 | |
18 | undef $w; # destroy event watcher again |
18 | undef $w; # destroy event watcher again |
19 | |
19 | |
20 | my $w = EV::periodic 0, 60, sub { |
20 | my $w = EV::periodic 0, 60, 0, sub { |
21 | warn "is called every minute, on the minute, exactly"; |
21 | warn "is called every minute, on the minute, exactly"; |
22 | }; |
22 | }; |
23 | |
23 | |
24 | # IO |
24 | # IO |
25 | |
25 | |
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146 | callback invocation), regardless of wether the watcher was active or |
146 | callback invocation), regardless of wether the watcher was active or |
147 | not. |
147 | not. |
148 | |
148 | |
149 | $bool = $w->is_active |
149 | $bool = $w->is_active |
150 | Returns true if the watcher is active, false otherwise. |
150 | Returns true if the watcher is active, false otherwise. |
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151 | |
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152 | $current_data = $w->data |
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153 | $old_data = $w->data ($new_data) |
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154 | Queries a freely usable data scalar on the watcher and optionally |
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155 | changes it. This is a way to associate custom data with a watcher: |
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156 | |
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157 | my $w = EV::timer 60, 0, sub { |
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158 | warn $_[0]->data; |
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159 | }; |
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160 | $w->data ("print me!"); |
151 | |
161 | |
152 | $current_cb = $w->cb |
162 | $current_cb = $w->cb |
153 | $old_cb = $w->cb ($new_cb) |
163 | $old_cb = $w->cb ($new_cb) |
154 | Queries the callback on the watcher and optionally changes it. You |
164 | Queries the callback on the watcher and optionally changes it. You |
155 | can do this at any time without the watcher restarting. |
165 | can do this at any time without the watcher restarting. |
… | |
… | |
231 | This behaviour is useful when you have a timeout for some IO |
241 | This behaviour is useful when you have a timeout for some IO |
232 | operation. You create a timer object with the same value for $after |
242 | operation. You create a timer object with the same value for $after |
233 | and $repeat, and then, in the read/write watcher, run the "again" |
243 | and $repeat, and then, in the read/write watcher, run the "again" |
234 | method on the timeout. |
244 | method on the timeout. |
235 | |
245 | |
236 | $w = EV::periodic $at, $interval, $callback |
246 | $w = EV::periodic $at, $interval, $reschedule_cb, $callback |
237 | $w = EV::periodic_ns $at, $interval, $callback |
247 | $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback |
238 | Similar to EV::timer, but the time is given as an absolute point in |
248 | Similar to EV::timer, but is not based on relative timeouts but on |
239 | time ($at), plus an optional $interval. |
249 | absolute times. Apart from creating "simple" timers that trigger |
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250 | "at" the specified time, it can also be used for non-drifting |
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251 | absolute timers and more complex, cron-like, setups that are not |
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252 | adversely affected by time jumps (i.e. when the system clock is |
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253 | changed by explicit date -s or other means such as ntpd). It is also |
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254 | the most complex watcher type in EV. |
240 | |
255 | |
241 | If the $interval is zero, then the callback will be called at the |
256 | It has three distinct "modes": |
242 | time $at if that is in the future, or as soon as possible if it is |
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243 | in the past. It will not automatically repeat. |
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244 | |
257 | |
245 | If the $interval is nonzero, then the watcher will always be |
258 | * absolute timer ($interval = $reschedule_cb = 0) |
246 | scheduled to time out at the next "$at + N * $interval" time. |
259 | This time simply fires at the wallclock time $at and doesn't |
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260 | repeat. It will not adjust when a time jump occurs, that is, if |
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261 | it is to be run at January 1st 2011 then it will run when the |
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262 | system time reaches or surpasses this time. |
247 | |
263 | |
248 | This can be used to schedule a callback to run at very regular |
264 | * non-repeating interval timer ($interval > 0, $reschedule_cb = 0) |
249 | intervals, as long as the processing time is less then the interval |
265 | In this mode the watcher will always be scheduled to time out at |
250 | (otherwise obviously events will be skipped). |
266 | the next "$at + N * $interval" time (for some integer N) and |
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267 | then repeat, regardless of any time jumps. |
251 | |
268 | |
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269 | This can be used to create timers that do not drift with respect |
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270 | to system time: |
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271 | |
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272 | my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" }; |
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273 | |
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274 | That doesn't mean there will always be 3600 seconds in between |
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275 | triggers, but only that the the clalback will be called when the |
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276 | system time shows a full hour (UTC). |
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277 | |
252 | Another way to think about it (for the mathematically inclined) is |
278 | Another way to think about it (for the mathematically inclined) |
253 | that EV::periodic will try to run the callback at the next possible |
279 | is that EV::periodic will try to run the callback in this mode |
254 | time where "$time = $at (mod $interval)", regardless of any time |
280 | at the next possible time where "$time = $at (mod $interval)", |
255 | jumps. |
281 | regardless of any time jumps. |
256 | |
282 | |
257 | This periodic timer is based on "wallclock time", that is, if the |
283 | * manual reschedule mode ($reschedule_cb = coderef) |
258 | clock changes ("ntp", "date -s" etc.), then the timer will |
284 | In this mode $interval and $at are both being ignored. Instead, |
259 | nevertheless run at the specified time. This means it will never |
285 | each time the periodic watcher gets scheduled, the first |
260 | drift (it might jitter, but it will not drift). |
286 | callback ($reschedule_cb) will be called with the watcher as |
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287 | first, and the current time as second argument. |
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288 | |
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289 | *This callback MUST NOT stop or destroy this or any other |
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290 | periodic watcher, ever*. If you need to stop it, return 1e30 and |
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291 | stop it afterwards. |
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292 | |
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293 | It must return the next time to trigger, based on the passed |
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294 | time value (that is, the lowest time value larger than to the |
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295 | second argument). It will usually be called just before the |
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296 | callback will be triggered, but might be called at other times, |
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297 | too. |
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298 | |
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299 | This can be used to create very complex timers, such as a timer |
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300 | that triggers on each midnight, local time (actually 24 hours |
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301 | after the last midnight, to keep the example simple. If you know |
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302 | a way to do it correctly in about the same space (without |
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303 | requiring elaborate modules), drop me a note :): |
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304 | |
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305 | my $daily = EV::periodic 0, 0, sub { |
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306 | my ($w, $now) = @_; |
|
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307 | |
|
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308 | use Time::Local (); |
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309 | my (undef, undef, undef, $d, $m, $y) = localtime $now; |
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310 | 86400 + Time::Local::timelocal 0, 0, 0, $d, $m, $y |
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311 | }, sub { |
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312 | print "it's midnight or likely shortly after, now\n"; |
|
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313 | }; |
261 | |
314 | |
262 | The "periodic_ns" variant doesn't start (activate) the newly created |
315 | The "periodic_ns" variant doesn't start (activate) the newly created |
263 | watcher. |
316 | watcher. |
264 | |
317 | |
265 | $w->set ($at, $interval) |
318 | $w->set ($at, $interval, $reschedule_cb) |
266 | Reconfigures the watcher, see the constructor above for details. Can |
319 | Reconfigures the watcher, see the constructor above for details. Can |
267 | be at any time. |
320 | be at any time. |
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321 | |
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322 | $w->again |
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323 | Simply stops and starts the watcher again. |
268 | |
324 | |
269 | $w = EV::signal $signal, $callback |
325 | $w = EV::signal $signal, $callback |
270 | $w = EV::signal_ns $signal, $callback |
326 | $w = EV::signal_ns $signal, $callback |
271 | Call the callback when $signal is received (the signal can be |
327 | Call the callback when $signal is received (the signal can be |
272 | specified by number or by name, just as with kill or %SIG). |
328 | specified by number or by name, just as with kill or %SIG). |