| … | |
… | |
| 569 | kernel is more efficient (which says nothing about its actual speed, of |
569 | kernel is more efficient (which says nothing about its actual speed, of |
| 570 | course). While stopping, setting and starting an I/O watcher does never |
570 | course). While stopping, setting and starting an I/O watcher does never |
| 571 | cause an extra system call as with C<EVBACKEND_EPOLL>, it still adds up to |
571 | cause an extra system call as with C<EVBACKEND_EPOLL>, it still adds up to |
| 572 | two event changes per incident. Support for C<fork ()> is very bad (you |
572 | two event changes per incident. Support for C<fork ()> is very bad (you |
| 573 | might have to leak fd's on fork, but it's more sane than epoll) and it |
573 | might have to leak fd's on fork, but it's more sane than epoll) and it |
| 574 | drops fds silently in similarly hard-to-detect cases |
574 | drops fds silently in similarly hard-to-detect cases. |
| 575 | |
575 | |
| 576 | This backend usually performs well under most conditions. |
576 | This backend usually performs well under most conditions. |
| 577 | |
577 | |
| 578 | While nominally embeddable in other event loops, this doesn't work |
578 | While nominally embeddable in other event loops, this doesn't work |
| 579 | everywhere, so you might need to test for this. And since it is broken |
579 | everywhere, so you might need to test for this. And since it is broken |
| … | |
… | |
| 1393 | transition between them will be described in more detail - and while these |
1393 | transition between them will be described in more detail - and while these |
| 1394 | rules might look complicated, they usually do "the right thing". |
1394 | rules might look complicated, they usually do "the right thing". |
| 1395 | |
1395 | |
| 1396 | =over 4 |
1396 | =over 4 |
| 1397 | |
1397 | |
| 1398 | =item initialiased |
1398 | =item initialised |
| 1399 | |
1399 | |
| 1400 | Before a watcher can be registered with the event loop it has to be |
1400 | Before a watcher can be registered with the event loop it has to be |
| 1401 | initialised. This can be done with a call to C<ev_TYPE_init>, or calls to |
1401 | initialised. This can be done with a call to C<ev_TYPE_init>, or calls to |
| 1402 | C<ev_init> followed by the watcher-specific C<ev_TYPE_set> function. |
1402 | C<ev_init> followed by the watcher-specific C<ev_TYPE_set> function. |
| 1403 | |
1403 | |
| … | |
… | |
| 3177 | |
3177 | |
| 3178 | =over 4 |
3178 | =over 4 |
| 3179 | |
3179 | |
| 3180 | =item ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop) |
3180 | =item ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop) |
| 3181 | |
3181 | |
| 3182 | =item ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop) |
3182 | =item ev_embed_set (ev_embed *, struct ev_loop *embedded_loop) |
| 3183 | |
3183 | |
| 3184 | Configures the watcher to embed the given loop, which must be |
3184 | Configures the watcher to embed the given loop, which must be |
| 3185 | embeddable. If the callback is C<0>, then C<ev_embed_sweep> will be |
3185 | embeddable. If the callback is C<0>, then C<ev_embed_sweep> will be |
| 3186 | invoked automatically, otherwise it is the responsibility of the callback |
3186 | invoked automatically, otherwise it is the responsibility of the callback |
| 3187 | to invoke it (it will continue to be called until the sweep has been done, |
3187 | to invoke it (it will continue to be called until the sweep has been done, |
| … | |
… | |
| 3658 | already been invoked. |
3658 | already been invoked. |
| 3659 | |
3659 | |
| 3660 | A common way around all these issues is to make sure that |
3660 | A common way around all these issues is to make sure that |
| 3661 | C<start_new_request> I<always> returns before the callback is invoked. If |
3661 | C<start_new_request> I<always> returns before the callback is invoked. If |
| 3662 | C<start_new_request> immediately knows the result, it can artificially |
3662 | C<start_new_request> immediately knows the result, it can artificially |
| 3663 | delay invoking the callback by e.g. using a C<prepare> or C<idle> watcher |
3663 | delay invoking the callback by using a C<prepare> or C<idle> watcher for |
| 3664 | for example, or more sneakily, by reusing an existing (stopped) watcher |
3664 | example, or more sneakily, by reusing an existing (stopped) watcher and |
| 3665 | and pushing it into the pending queue: |
3665 | pushing it into the pending queue: |
| 3666 | |
3666 | |
| 3667 | ev_set_cb (watcher, callback); |
3667 | ev_set_cb (watcher, callback); |
| 3668 | ev_feed_event (EV_A_ watcher, 0); |
3668 | ev_feed_event (EV_A_ watcher, 0); |
| 3669 | |
3669 | |
| 3670 | This way, C<start_new_request> can safely return before the callback is |
3670 | This way, C<start_new_request> can safely return before the callback is |
| … | |
… | |
| 3678 | |
3678 | |
| 3679 | This brings the problem of exiting - a callback might want to finish the |
3679 | This brings the problem of exiting - a callback might want to finish the |
| 3680 | main C<ev_run> call, but not the nested one (e.g. user clicked "Quit", but |
3680 | main C<ev_run> call, but not the nested one (e.g. user clicked "Quit", but |
| 3681 | a modal "Are you sure?" dialog is still waiting), or just the nested one |
3681 | a modal "Are you sure?" dialog is still waiting), or just the nested one |
| 3682 | and not the main one (e.g. user clocked "Ok" in a modal dialog), or some |
3682 | and not the main one (e.g. user clocked "Ok" in a modal dialog), or some |
| 3683 | other combination: In these cases, C<ev_break> will not work alone. |
3683 | other combination: In these cases, a simple C<ev_break> will not work. |
| 3684 | |
3684 | |
| 3685 | The solution is to maintain "break this loop" variable for each C<ev_run> |
3685 | The solution is to maintain "break this loop" variable for each C<ev_run> |
| 3686 | invocation, and use a loop around C<ev_run> until the condition is |
3686 | invocation, and use a loop around C<ev_run> until the condition is |
| 3687 | triggered, using C<EVRUN_ONCE>: |
3687 | triggered, using C<EVRUN_ONCE>: |
| 3688 | |
3688 | |
