| … | |
… | |
| 232 | on true relative time) and absolute (ev_periodic, based on wallclock time) |
232 | on true relative time) and absolute (ev_periodic, based on wallclock time) |
| 233 | timers. |
233 | timers. |
| 234 | |
234 | |
| 235 | AnyEvent always prefers relative timers, if available, matching the |
235 | AnyEvent always prefers relative timers, if available, matching the |
| 236 | AnyEvent API. |
236 | AnyEvent API. |
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237 | |
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238 | AnyEvent has two additional methods that return the "current time": |
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239 | |
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240 | =over 4 |
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241 | |
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242 | =item AnyEvent->time |
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243 | |
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244 | This returns the "current wallclock time" as a fractional number of |
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245 | seconds since the Epoch (the same thing as C<time> or C<Time::HiRes::time> |
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246 | return, and the result is guaranteed to be compatible with those). |
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247 | |
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248 | It progresses independently of any event loop processing. |
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249 | |
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250 | In almost all cases (in all cases if you don't care), this is the function |
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251 | to call when you want to know the current time. |
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252 | |
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253 | =item AnyEvent->now |
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254 | |
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255 | This also returns the "current wallclock time", but unlike C<time>, above, |
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256 | this value might change only once per event loop iteration, depending on |
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257 | the event loop (most return the same time as C<time>, above). This is the |
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258 | time that AnyEvent timers get scheduled against. |
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259 | |
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260 | For a practical example of when these times differ, consider L<Event::Lib> |
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261 | and L<EV> and the following set-up: |
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262 | |
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263 | The event loop is running and has just invoked one of your callback at |
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264 | time=500 (assume no other callbacks delay processing). In your callback, |
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265 | you wait a second by executing C<sleep 1> (blocking the process for a |
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266 | second) and then (at time=501) you create a relative timer that fires |
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267 | after three seconds. |
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268 | |
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269 | With L<Event::Lib>, C<< AnyEvent->time >> and C<< AnyEvent->now >> will |
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270 | both return C<501>, because that is the current time, and the timer will |
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271 | be scheduled to fire at time=504 (C<501> + C<3>). |
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272 | |
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273 | With L<EV>m C<< AnyEvent->time >> returns C<501> (as that is the current |
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274 | time), but C<< AnyEvent->now >> returns C<500>, as that is the time the |
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275 | last event processing phase started. With L<EV>, your timer gets scheduled |
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276 | to run at time=503 (C<500> + C<3>). |
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277 | |
|
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278 | In one sense, L<Event::Lib> is more exact, as it uses the current time |
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279 | regardless of any delays introduced by event processing. However, most |
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280 | callbacks do not expect large delays in processing, so this causes a |
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281 | higher drift (and a lot more syscalls to get the current time). |
|
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282 | |
|
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283 | In another sense, L<EV> is more exact, as your timer will be scheduled at |
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284 | the same time, regardless of how long event processing actually took. |
|
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285 | |
|
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286 | In either case, if you care (and in most cases, you don't), then you |
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287 | can get whatever behaviour you want with any event loop, by taking the |
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288 | difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into |
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289 | account. |
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290 | |
|
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291 | =back |
| 237 | |
292 | |
| 238 | =head2 SIGNAL WATCHERS |
293 | =head2 SIGNAL WATCHERS |
| 239 | |
294 | |
| 240 | You can watch for signals using a signal watcher, C<signal> is the signal |
295 | You can watch for signals using a signal watcher, C<signal> is the signal |
| 241 | I<name> without any C<SIG> prefix, C<cb> is the Perl callback to |
296 | I<name> without any C<SIG> prefix, C<cb> is the Perl callback to |
| … | |
… | |
| 779 | [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza |
834 | [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza |
| 780 | [Wx:: => AnyEvent::Impl::POE::], |
835 | [Wx:: => AnyEvent::Impl::POE::], |
| 781 | [Prima:: => AnyEvent::Impl::POE::], |
836 | [Prima:: => AnyEvent::Impl::POE::], |
| 782 | ); |
837 | ); |
| 783 | |
838 | |
| 784 | our %method = map +($_ => 1), qw(io timer signal child condvar one_event DESTROY); |
839 | our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY); |
| 785 | |
840 | |
| 786 | our @post_detect; |
841 | our @post_detect; |
| 787 | |
842 | |
| 788 | sub post_detect(&) { |
843 | sub post_detect(&) { |
| 789 | my ($cb) = @_; |
844 | my ($cb) = @_; |
| … | |
… | |
| 873 | $class->$func (@_); |
928 | $class->$func (@_); |
| 874 | } |
929 | } |
| 875 | |
930 | |
| 876 | package AnyEvent::Base; |
931 | package AnyEvent::Base; |
| 877 | |
932 | |
|
|
933 | # default implementation for now and time |
|
|
934 | |
|
|
935 | use Time::HiRes (); |
|
|
936 | |
|
|
937 | sub time { Time::HiRes::time } |
|
|
938 | sub now { Time::HiRes::time } |
|
|
939 | |
| 878 | # default implementation for ->condvar |
940 | # default implementation for ->condvar |
| 879 | |
941 | |
| 880 | sub condvar { |
942 | sub condvar { |
| 881 | bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar:: |
943 | bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar:: |
| 882 | } |
944 | } |
