| … | |
… | |
| 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 | |
| … | |
… | |
| 2962 | |
2962 | |
| 2963 | Using an C<ev_check> watcher is almost enough: it will be called on the |
2963 | Using an C<ev_check> watcher is almost enough: it will be called on the |
| 2964 | next event loop iteration. However, that isn't as soon as possible - |
2964 | next event loop iteration. However, that isn't as soon as possible - |
| 2965 | without external events, your C<ev_check> watcher will not be invoked. |
2965 | without external events, your C<ev_check> watcher will not be invoked. |
| 2966 | |
2966 | |
| 2967 | |
|
|
| 2968 | This is where C<ev_idle> watchers come in handy - all you need is a |
2967 | This is where C<ev_idle> watchers come in handy - all you need is a |
| 2969 | single global idle watcher that is active as long as you have one active |
2968 | single global idle watcher that is active as long as you have one active |
| 2970 | C<ev_check> watcher. The C<ev_idle> watcher makes sure the event loop |
2969 | C<ev_check> watcher. The C<ev_idle> watcher makes sure the event loop |
| 2971 | will not sleep, and the C<ev_check> watcher makes sure a callback gets |
2970 | will not sleep, and the C<ev_check> watcher makes sure a callback gets |
| 2972 | invoked. Neither watcher alone can do that. |
2971 | invoked. Neither watcher alone can do that. |
| … | |
… | |
| 3251 | |
3250 | |
| 3252 | =head2 C<ev_fork> - the audacity to resume the event loop after a fork |
3251 | =head2 C<ev_fork> - the audacity to resume the event loop after a fork |
| 3253 | |
3252 | |
| 3254 | Fork watchers are called when a C<fork ()> was detected (usually because |
3253 | Fork watchers are called when a C<fork ()> was detected (usually because |
| 3255 | whoever is a good citizen cared to tell libev about it by calling |
3254 | whoever is a good citizen cared to tell libev about it by calling |
| 3256 | C<ev_default_fork> or C<ev_loop_fork>). The invocation is done before the |
3255 | C<ev_loop_fork>). The invocation is done before the event loop blocks next |
| 3257 | event loop blocks next and before C<ev_check> watchers are being called, |
3256 | and before C<ev_check> watchers are being called, and only in the child |
| 3258 | and only in the child after the fork. If whoever good citizen calling |
3257 | after the fork. If whoever good citizen calling C<ev_default_fork> cheats |
| 3259 | C<ev_default_fork> cheats and calls it in the wrong process, the fork |
3258 | and calls it in the wrong process, the fork handlers will be invoked, too, |
| 3260 | handlers will be invoked, too, of course. |
3259 | of course. |
| 3261 | |
3260 | |
| 3262 | =head3 The special problem of life after fork - how is it possible? |
3261 | =head3 The special problem of life after fork - how is it possible? |
| 3263 | |
3262 | |
| 3264 | Most uses of C<fork()> consist of forking, then some simple calls to set |
3263 | Most uses of C<fork()> consist of forking, then some simple calls to set |
| 3265 | up/change the process environment, followed by a call to C<exec()>. This |
3264 | up/change the process environment, followed by a call to C<exec()>. This |
| … | |
… | |
| 5311 | thread" or will block signals process-wide, both behaviours would |
5310 | thread" or will block signals process-wide, both behaviours would |
| 5312 | be compatible with libev. Interaction between C<sigprocmask> and |
5311 | be compatible with libev. Interaction between C<sigprocmask> and |
| 5313 | C<pthread_sigmask> could complicate things, however. |
5312 | C<pthread_sigmask> could complicate things, however. |
| 5314 | |
5313 | |
| 5315 | The most portable way to handle signals is to block signals in all threads |
5314 | The most portable way to handle signals is to block signals in all threads |
| 5316 | except the initial one, and run the default loop in the initial thread as |
5315 | except the initial one, and run the signal handling loop in the initial |
| 5317 | well. |
5316 | thread as well. |
| 5318 | |
5317 | |
| 5319 | =item C<long> must be large enough for common memory allocation sizes |
5318 | =item C<long> must be large enough for common memory allocation sizes |
| 5320 | |
5319 | |
| 5321 | To improve portability and simplify its API, libev uses C<long> internally |
5320 | To improve portability and simplify its API, libev uses C<long> internally |
| 5322 | instead of C<size_t> when allocating its data structures. On non-POSIX |
5321 | instead of C<size_t> when allocating its data structures. On non-POSIX |
