… | |
… | |
460 | |
460 | |
461 | While nominally embeddable in other event loops, this doesn't work |
461 | While nominally embeddable in other event loops, this doesn't work |
462 | everywhere, so you might need to test for this. And since it is broken |
462 | everywhere, so you might need to test for this. And since it is broken |
463 | almost everywhere, you should only use it when you have a lot of sockets |
463 | almost everywhere, you should only use it when you have a lot of sockets |
464 | (for which it usually works), by embedding it into another event loop |
464 | (for which it usually works), by embedding it into another event loop |
465 | (e.g. C<EVBACKEND_SELECT> or C<EVBACKEND_POLL>) and, did I mention it, |
465 | (e.g. C<EVBACKEND_SELECT> or C<EVBACKEND_POLL> (but C<poll> is of course |
466 | using it only for sockets. |
466 | also broken on OS X)) and, did I mention it, using it only for sockets. |
467 | |
467 | |
468 | This backend maps C<EV_READ> into an C<EVFILT_READ> kevent with |
468 | This backend maps C<EV_READ> into an C<EVFILT_READ> kevent with |
469 | C<NOTE_EOF>, and C<EV_WRITE> into an C<EVFILT_WRITE> kevent with |
469 | C<NOTE_EOF>, and C<EV_WRITE> into an C<EVFILT_WRITE> kevent with |
470 | C<NOTE_EOF>. |
470 | C<NOTE_EOF>. |
471 | |
471 | |
… | |
… | |
2012 | the process. The exception are C<ev_stat> watchers - those call C<stat |
2012 | the process. The exception are C<ev_stat> watchers - those call C<stat |
2013 | ()>, which is a synchronous operation. |
2013 | ()>, which is a synchronous operation. |
2014 | |
2014 | |
2015 | For local paths, this usually doesn't matter: unless the system is very |
2015 | For local paths, this usually doesn't matter: unless the system is very |
2016 | busy or the intervals between stat's are large, a stat call will be fast, |
2016 | busy or the intervals between stat's are large, a stat call will be fast, |
2017 | as the path data is suually in memory already (except when starting the |
2017 | as the path data is usually in memory already (except when starting the |
2018 | watcher). |
2018 | watcher). |
2019 | |
2019 | |
2020 | For networked file systems, calling C<stat ()> can block an indefinite |
2020 | For networked file systems, calling C<stat ()> can block an indefinite |
2021 | time due to network issues, and even under good conditions, a stat call |
2021 | time due to network issues, and even under good conditions, a stat call |
2022 | often takes multiple milliseconds. |
2022 | often takes multiple milliseconds. |
… | |
… | |
2428 | some fds have to be watched and handled very quickly (with low latency), |
2428 | some fds have to be watched and handled very quickly (with low latency), |
2429 | and even priorities and idle watchers might have too much overhead. In |
2429 | and even priorities and idle watchers might have too much overhead. In |
2430 | this case you would put all the high priority stuff in one loop and all |
2430 | this case you would put all the high priority stuff in one loop and all |
2431 | the rest in a second one, and embed the second one in the first. |
2431 | the rest in a second one, and embed the second one in the first. |
2432 | |
2432 | |
2433 | As long as the watcher is active, the callback will be invoked every time |
2433 | As long as the watcher is active, the callback will be invoked every |
2434 | there might be events pending in the embedded loop. The callback must then |
2434 | time there might be events pending in the embedded loop. The callback |
2435 | call C<ev_embed_sweep (mainloop, watcher)> to make a single sweep and invoke |
2435 | must then call C<ev_embed_sweep (mainloop, watcher)> to make a single |
2436 | their callbacks (you could also start an idle watcher to give the embedded |
2436 | sweep and invoke their callbacks (the callback doesn't need to invoke the |
2437 | loop strictly lower priority for example). You can also set the callback |
2437 | C<ev_embed_sweep> function directly, it could also start an idle watcher |
2438 | to C<0>, in which case the embed watcher will automatically execute the |
2438 | to give the embedded loop strictly lower priority for example). |
2439 | embedded loop sweep. |
|
|
2440 | |
2439 | |
2441 | As long as the watcher is started it will automatically handle events. The |
2440 | You can also set the callback to C<0>, in which case the embed watcher |
2442 | callback will be invoked whenever some events have been handled. You can |
2441 | will automatically execute the embedded loop sweep whenever necessary. |
2443 | set the callback to C<0> to avoid having to specify one if you are not |
|
|
2444 | interested in that. |
|
|
2445 | |
2442 | |
2446 | Also, there have not currently been made special provisions for forking: |
2443 | Fork detection will be handled transparently while the C<ev_embed> watcher |
2447 | when you fork, you not only have to call C<ev_loop_fork> on both loops, |
2444 | is active, i.e., the embedded loop will automatically be forked when the |
2448 | but you will also have to stop and restart any C<ev_embed> watchers |
2445 | embedding loop forks. In other cases, the user is responsible for calling |
2449 | yourself - but you can use a fork watcher to handle this automatically, |
2446 | C<ev_loop_fork> on the embedded loop. |
2450 | and future versions of libev might do just that. |
|
|
2451 | |
2447 | |
2452 | Unfortunately, not all backends are embeddable: only the ones returned by |
2448 | Unfortunately, not all backends are embeddable: only the ones returned by |
2453 | C<ev_embeddable_backends> are, which, unfortunately, does not include any |
2449 | C<ev_embeddable_backends> are, which, unfortunately, does not include any |
2454 | portable one. |
2450 | portable one. |
2455 | |
2451 | |
… | |
… | |
2891 | |
2887 | |
2892 | myclass obj; |
2888 | myclass obj; |
2893 | ev::io iow; |
2889 | ev::io iow; |
2894 | iow.set <myclass, &myclass::io_cb> (&obj); |
2890 | iow.set <myclass, &myclass::io_cb> (&obj); |
2895 | |
2891 | |
|
|
2892 | =item w->set (object *) |
|
|
2893 | |
|
|
2894 | This is an B<experimental> feature that might go away in a future version. |
|
|
2895 | |
|
|
2896 | This is a variation of a method callback - leaving out the method to call |
|
|
2897 | will default the method to C<operator ()>, which makes it possible to use |
|
|
2898 | functor objects without having to manually specify the C<operator ()> all |
|
|
2899 | the time. Incidentally, you can then also leave out the template argument |
|
|
2900 | list. |
|
|
2901 | |
|
|
2902 | The C<operator ()> method prototype must be C<void operator ()(watcher &w, |
|
|
2903 | int revents)>. |
|
|
2904 | |
|
|
2905 | See the method-C<set> above for more details. |
|
|
2906 | |
|
|
2907 | Example: use a functor object as callback. |
|
|
2908 | |
|
|
2909 | struct myfunctor |
|
|
2910 | { |
|
|
2911 | void operator() (ev::io &w, int revents) |
|
|
2912 | { |
|
|
2913 | ... |
|
|
2914 | } |
|
|
2915 | } |
|
|
2916 | |
|
|
2917 | myfunctor f; |
|
|
2918 | |
|
|
2919 | ev::io w; |
|
|
2920 | w.set (&f); |
|
|
2921 | |
2896 | =item w->set<function> (void *data = 0) |
2922 | =item w->set<function> (void *data = 0) |
2897 | |
2923 | |
2898 | Also sets a callback, but uses a static method or plain function as |
2924 | Also sets a callback, but uses a static method or plain function as |
2899 | callback. The optional C<data> argument will be stored in the watcher's |
2925 | callback. The optional C<data> argument will be stored in the watcher's |
2900 | C<data> member and is free for you to use. |
2926 | C<data> member and is free for you to use. |
… | |
… | |
3203 | function is hiding in (often F<-lrt>). See also C<EV_USE_CLOCK_SYSCALL>. |
3229 | function is hiding in (often F<-lrt>). See also C<EV_USE_CLOCK_SYSCALL>. |
3204 | |
3230 | |
3205 | =item EV_USE_REALTIME |
3231 | =item EV_USE_REALTIME |
3206 | |
3232 | |
3207 | If defined to be C<1>, libev will try to detect the availability of the |
3233 | If defined to be C<1>, libev will try to detect the availability of the |
3208 | real-time clock option at compile time (and assume its availability at |
3234 | real-time clock option at compile time (and assume its availability |
3209 | runtime if successful). Otherwise no use of the real-time clock option will |
3235 | at runtime if successful). Otherwise no use of the real-time clock |
3210 | be attempted. This effectively replaces C<gettimeofday> by C<clock_get |
3236 | option will be attempted. This effectively replaces C<gettimeofday> |
3211 | (CLOCK_REALTIME, ...)> and will not normally affect correctness. See the |
3237 | by C<clock_get (CLOCK_REALTIME, ...)> and will not normally affect |
3212 | note about libraries in the description of C<EV_USE_MONOTONIC>, though. |
3238 | correctness. See the note about libraries in the description of |
|
|
3239 | C<EV_USE_MONOTONIC>, though. Defaults to the opposite value of |
|
|
3240 | C<EV_USE_CLOCK_SYSCALL>. |
3213 | |
3241 | |
3214 | =item EV_USE_CLOCK_SYSCALL |
3242 | =item EV_USE_CLOCK_SYSCALL |
3215 | |
3243 | |
3216 | If defined to be C<1>, libev will try to use a direct syscall instead |
3244 | If defined to be C<1>, libev will try to use a direct syscall instead |
3217 | of calling the system-provided C<clock_gettime> function. This option |
3245 | of calling the system-provided C<clock_gettime> function. This option |