… | |
… | |
58 | ev_timer_start (loop, &timeout_watcher); |
58 | ev_timer_start (loop, &timeout_watcher); |
59 | |
59 | |
60 | // now wait for events to arrive |
60 | // now wait for events to arrive |
61 | ev_run (loop, 0); |
61 | ev_run (loop, 0); |
62 | |
62 | |
63 | // unloop was called, so exit |
63 | // break was called, so exit |
64 | return 0; |
64 | return 0; |
65 | } |
65 | } |
66 | |
66 | |
67 | =head1 ABOUT THIS DOCUMENT |
67 | =head1 ABOUT THIS DOCUMENT |
68 | |
68 | |
… | |
… | |
483 | =item C<EVBACKEND_EPOLL> (value 4, Linux) |
483 | =item C<EVBACKEND_EPOLL> (value 4, Linux) |
484 | |
484 | |
485 | Use the linux-specific epoll(7) interface (for both pre- and post-2.6.9 |
485 | Use the linux-specific epoll(7) interface (for both pre- and post-2.6.9 |
486 | kernels). |
486 | kernels). |
487 | |
487 | |
488 | For few fds, this backend is a bit little slower than poll and select, |
488 | For few fds, this backend is a bit little slower than poll and select, but |
489 | but it scales phenomenally better. While poll and select usually scale |
489 | it scales phenomenally better. While poll and select usually scale like |
490 | like O(total_fds) where n is the total number of fds (or the highest fd), |
490 | O(total_fds) where total_fds is the total number of fds (or the highest |
491 | epoll scales either O(1) or O(active_fds). |
491 | fd), epoll scales either O(1) or O(active_fds). |
492 | |
492 | |
493 | The epoll mechanism deserves honorable mention as the most misdesigned |
493 | The epoll mechanism deserves honorable mention as the most misdesigned |
494 | of the more advanced event mechanisms: mere annoyances include silently |
494 | of the more advanced event mechanisms: mere annoyances include silently |
495 | dropping file descriptors, requiring a system call per change per file |
495 | dropping file descriptors, requiring a system call per change per file |
496 | descriptor (and unnecessary guessing of parameters), problems with dup, |
496 | descriptor (and unnecessary guessing of parameters), problems with dup, |
… | |
… | |
825 | This is useful if you are waiting for some external event in conjunction |
825 | This is useful if you are waiting for some external event in conjunction |
826 | with something not expressible using other libev watchers (i.e. "roll your |
826 | with something not expressible using other libev watchers (i.e. "roll your |
827 | own C<ev_run>"). However, a pair of C<ev_prepare>/C<ev_check> watchers is |
827 | own C<ev_run>"). However, a pair of C<ev_prepare>/C<ev_check> watchers is |
828 | usually a better approach for this kind of thing. |
828 | usually a better approach for this kind of thing. |
829 | |
829 | |
830 | Here are the gory details of what C<ev_run> does: |
830 | Here are the gory details of what C<ev_run> does (this is for your |
|
|
831 | understanding, not a guarantee that things will work exactly like this in |
|
|
832 | future versions): |
831 | |
833 | |
832 | - Increment loop depth. |
834 | - Increment loop depth. |
833 | - Reset the ev_break status. |
835 | - Reset the ev_break status. |
834 | - Before the first iteration, call any pending watchers. |
836 | - Before the first iteration, call any pending watchers. |
835 | LOOP: |
837 | LOOP: |
… | |
… | |
868 | anymore. |
870 | anymore. |
869 | |
871 | |
870 | ... queue jobs here, make sure they register event watchers as long |
872 | ... queue jobs here, make sure they register event watchers as long |
871 | ... as they still have work to do (even an idle watcher will do..) |
873 | ... as they still have work to do (even an idle watcher will do..) |
872 | ev_run (my_loop, 0); |
874 | ev_run (my_loop, 0); |
873 | ... jobs done or somebody called unloop. yeah! |
875 | ... jobs done or somebody called break. yeah! |
874 | |
876 | |
875 | =item ev_break (loop, how) |
877 | =item ev_break (loop, how) |
876 | |
878 | |
877 | Can be used to make a call to C<ev_run> return early (but only after it |
879 | Can be used to make a call to C<ev_run> return early (but only after it |
878 | has processed all outstanding events). The C<how> argument must be either |
880 | has processed all outstanding events). The C<how> argument must be either |
… | |
… | |
1378 | |
1380 | |
1379 | Before a watcher can be registered with the event looop it has to be |
1381 | Before a watcher can be registered with the event looop it has to be |
1380 | initialised. This can be done with a call to C<ev_TYPE_init>, or calls to |
1382 | initialised. This can be done with a call to C<ev_TYPE_init>, or calls to |
1381 | C<ev_init> followed by the watcher-specific C<ev_TYPE_set> function. |
1383 | C<ev_init> followed by the watcher-specific C<ev_TYPE_set> function. |
1382 | |
1384 | |
1383 | In this state it is simply some block of memory that is suitable for use |
1385 | In this state it is simply some block of memory that is suitable for |
1384 | in an event loop. It can be moved around, freed, reused etc. at will. |
1386 | use in an event loop. It can be moved around, freed, reused etc. at |
|
|
1387 | will - as long as you either keep the memory contents intact, or call |
|
|
1388 | C<ev_TYPE_init> again. |
1385 | |
1389 | |
1386 | =item started/running/active |
1390 | =item started/running/active |
1387 | |
1391 | |
1388 | Once a watcher has been started with a call to C<ev_TYPE_start> it becomes |
1392 | Once a watcher has been started with a call to C<ev_TYPE_start> it becomes |
1389 | property of the event loop, and is actively waiting for events. While in |
1393 | property of the event loop, and is actively waiting for events. While in |
… | |
… | |
1417 | latter will clear any pending state the watcher might be in, regardless |
1421 | latter will clear any pending state the watcher might be in, regardless |
1418 | of whether it was active or not, so stopping a watcher explicitly before |
1422 | of whether it was active or not, so stopping a watcher explicitly before |
1419 | freeing it is often a good idea. |
1423 | freeing it is often a good idea. |
1420 | |
1424 | |
1421 | While stopped (and not pending) the watcher is essentially in the |
1425 | While stopped (and not pending) the watcher is essentially in the |
1422 | initialised state, that is it can be reused, moved, modified in any way |
1426 | initialised state, that is, it can be reused, moved, modified in any way |
1423 | you wish. |
1427 | you wish (but when you trash the memory block, you need to C<ev_TYPE_init> |
|
|
1428 | it again). |
1424 | |
1429 | |
1425 | =back |
1430 | =back |
1426 | |
1431 | |
1427 | =head2 WATCHER PRIORITY MODELS |
1432 | =head2 WATCHER PRIORITY MODELS |
1428 | |
1433 | |
… | |
… | |
2148 | |
2153 | |
2149 | Another way to think about it (for the mathematically inclined) is that |
2154 | Another way to think about it (for the mathematically inclined) is that |
2150 | C<ev_periodic> will try to run the callback in this mode at the next possible |
2155 | C<ev_periodic> will try to run the callback in this mode at the next possible |
2151 | time where C<time = offset (mod interval)>, regardless of any time jumps. |
2156 | time where C<time = offset (mod interval)>, regardless of any time jumps. |
2152 | |
2157 | |
2153 | For numerical stability it is preferable that the C<offset> value is near |
2158 | The C<interval> I<MUST> be positive, and for numerical stability, the |
2154 | C<ev_now ()> (the current time), but there is no range requirement for |
2159 | interval value should be higher than C<1/8192> (which is around 100 |
2155 | this value, and in fact is often specified as zero. |
2160 | microseconds) and C<offset> should be higher than C<0> and should have |
|
|
2161 | at most a similar magnitude as the current time (say, within a factor of |
|
|
2162 | ten). Typical values for offset are, in fact, C<0> or something between |
|
|
2163 | C<0> and C<interval>, which is also the recommended range. |
2156 | |
2164 | |
2157 | Note also that there is an upper limit to how often a timer can fire (CPU |
2165 | Note also that there is an upper limit to how often a timer can fire (CPU |
2158 | speed for example), so if C<interval> is very small then timing stability |
2166 | speed for example), so if C<interval> is very small then timing stability |
2159 | will of course deteriorate. Libev itself tries to be exact to be about one |
2167 | will of course deteriorate. Libev itself tries to be exact to be about one |
2160 | millisecond (if the OS supports it and the machine is fast enough). |
2168 | millisecond (if the OS supports it and the machine is fast enough). |
… | |
… | |
3185 | atexit (program_exits); |
3193 | atexit (program_exits); |
3186 | |
3194 | |
3187 | |
3195 | |
3188 | =head2 C<ev_async> - how to wake up an event loop |
3196 | =head2 C<ev_async> - how to wake up an event loop |
3189 | |
3197 | |
3190 | In general, you cannot use an C<ev_run> from multiple threads or other |
3198 | In general, you cannot use an C<ev_loop> from multiple threads or other |
3191 | asynchronous sources such as signal handlers (as opposed to multiple event |
3199 | asynchronous sources such as signal handlers (as opposed to multiple event |
3192 | loops - those are of course safe to use in different threads). |
3200 | loops - those are of course safe to use in different threads). |
3193 | |
3201 | |
3194 | Sometimes, however, you need to wake up an event loop you do not control, |
3202 | Sometimes, however, you need to wake up an event loop you do not control, |
3195 | for example because it belongs to another thread. This is what C<ev_async> |
3203 | for example because it belongs to another thread. This is what C<ev_async> |
… | |
… | |
3305 | trust me. |
3313 | trust me. |
3306 | |
3314 | |
3307 | =item ev_async_send (loop, ev_async *) |
3315 | =item ev_async_send (loop, ev_async *) |
3308 | |
3316 | |
3309 | Sends/signals/activates the given C<ev_async> watcher, that is, feeds |
3317 | Sends/signals/activates the given C<ev_async> watcher, that is, feeds |
3310 | an C<EV_ASYNC> event on the watcher into the event loop. Unlike |
3318 | an C<EV_ASYNC> event on the watcher into the event loop, and instantly |
|
|
3319 | returns. |
|
|
3320 | |
3311 | C<ev_feed_event>, this call is safe to do from other threads, signal or |
3321 | Unlike C<ev_feed_event>, this call is safe to do from other threads, |
3312 | similar contexts (see the discussion of C<EV_ATOMIC_T> in the embedding |
3322 | signal or similar contexts (see the discussion of C<EV_ATOMIC_T> in the |
3313 | section below on what exactly this means). |
3323 | embedding section below on what exactly this means). |
3314 | |
3324 | |
3315 | Note that, as with other watchers in libev, multiple events might get |
3325 | Note that, as with other watchers in libev, multiple events might get |
3316 | compressed into a single callback invocation (another way to look at this |
3326 | compressed into a single callback invocation (another way to look at this |
3317 | is that C<ev_async> watchers are level-triggered, set on C<ev_async_send>, |
3327 | is that C<ev_async> watchers are level-triggered, set on C<ev_async_send>, |
3318 | reset when the event loop detects that). |
3328 | reset when the event loop detects that). |
… | |
… | |
3544 | // now associate this with the loop |
3554 | // now associate this with the loop |
3545 | ev_set_userdata (EV_A_ u); |
3555 | ev_set_userdata (EV_A_ u); |
3546 | ev_set_invoke_pending_cb (EV_A_ l_invoke); |
3556 | ev_set_invoke_pending_cb (EV_A_ l_invoke); |
3547 | ev_set_loop_release_cb (EV_A_ l_release, l_acquire); |
3557 | ev_set_loop_release_cb (EV_A_ l_release, l_acquire); |
3548 | |
3558 | |
3549 | // then create the thread running ev_loop |
3559 | // then create the thread running ev_run |
3550 | pthread_create (&u->tid, 0, l_run, EV_A); |
3560 | pthread_create (&u->tid, 0, l_run, EV_A); |
3551 | } |
3561 | } |
3552 | |
3562 | |
3553 | The callback for the C<ev_async> watcher does nothing: the watcher is used |
3563 | The callback for the C<ev_async> watcher does nothing: the watcher is used |
3554 | solely to wake up the event loop so it takes notice of any new watchers |
3564 | solely to wake up the event loop so it takes notice of any new watchers |
… | |
… | |
4199 | F<event.h> that are not directly supported by the libev core alone. |
4209 | F<event.h> that are not directly supported by the libev core alone. |
4200 | |
4210 | |
4201 | In standalone mode, libev will still try to automatically deduce the |
4211 | In standalone mode, libev will still try to automatically deduce the |
4202 | configuration, but has to be more conservative. |
4212 | configuration, but has to be more conservative. |
4203 | |
4213 | |
|
|
4214 | =item EV_USE_FLOOR |
|
|
4215 | |
|
|
4216 | If defined to be C<1>, libev will use the C<floor ()> function for its |
|
|
4217 | periodic reschedule calculations, otherwise libev will fall back on a |
|
|
4218 | portable (slower) implementation. If you enable this, you usually have to |
|
|
4219 | link against libm or something equivalent. Enabling this when the C<floor> |
|
|
4220 | function is not available will fail, so the safe default is to not enable |
|
|
4221 | this. |
|
|
4222 | |
4204 | =item EV_USE_MONOTONIC |
4223 | =item EV_USE_MONOTONIC |
4205 | |
4224 | |
4206 | If defined to be C<1>, libev will try to detect the availability of the |
4225 | If defined to be C<1>, libev will try to detect the availability of the |
4207 | monotonic clock option at both compile time and runtime. Otherwise no |
4226 | monotonic clock option at both compile time and runtime. Otherwise no |
4208 | use of the monotonic clock option will be attempted. If you enable this, |
4227 | use of the monotonic clock option will be attempted. If you enable this, |
… | |
… | |
5219 | The physical time that is observed. It is apparently strictly monotonic :) |
5238 | The physical time that is observed. It is apparently strictly monotonic :) |
5220 | |
5239 | |
5221 | =item wall-clock time |
5240 | =item wall-clock time |
5222 | |
5241 | |
5223 | The time and date as shown on clocks. Unlike real time, it can actually |
5242 | The time and date as shown on clocks. Unlike real time, it can actually |
5224 | be wrong and jump forwards and backwards, e.g. when the you adjust your |
5243 | be wrong and jump forwards and backwards, e.g. when you adjust your |
5225 | clock. |
5244 | clock. |
5226 | |
5245 | |
5227 | =item watcher |
5246 | =item watcher |
5228 | |
5247 | |
5229 | A data structure that describes interest in certain events. Watchers need |
5248 | A data structure that describes interest in certain events. Watchers need |
… | |
… | |
5232 | =back |
5251 | =back |
5233 | |
5252 | |
5234 | =head1 AUTHOR |
5253 | =head1 AUTHOR |
5235 | |
5254 | |
5236 | Marc Lehmann <libev@schmorp.de>, with repeated corrections by Mikael |
5255 | Marc Lehmann <libev@schmorp.de>, with repeated corrections by Mikael |
5237 | Magnusson and Emanuele Giaquinta. |
5256 | Magnusson and Emanuele Giaquinta, and minor corrections by many others. |
5238 | |
5257 | |