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241 | the current system, you would need to look at C<ev_embeddable_backends () |
241 | the current system, you would need to look at C<ev_embeddable_backends () |
242 | & ev_supported_backends ()>, likewise for recommended ones. |
242 | & ev_supported_backends ()>, likewise for recommended ones. |
243 | |
243 | |
244 | See the description of C<ev_embed> watchers for more info. |
244 | See the description of C<ev_embed> watchers for more info. |
245 | |
245 | |
246 | =item ev_set_allocator (void *(*cb)(void *ptr, long size)) [NOT REENTRANT] |
246 | =item ev_set_allocator (void *(*cb)(void *ptr, long size)) |
247 | |
247 | |
248 | Sets the allocation function to use (the prototype is similar - the |
248 | Sets the allocation function to use (the prototype is similar - the |
249 | semantics are identical to the C<realloc> C89/SuS/POSIX function). It is |
249 | semantics are identical to the C<realloc> C89/SuS/POSIX function). It is |
250 | used to allocate and free memory (no surprises here). If it returns zero |
250 | used to allocate and free memory (no surprises here). If it returns zero |
251 | when memory needs to be allocated (C<size != 0>), the library might abort |
251 | when memory needs to be allocated (C<size != 0>), the library might abort |
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277 | } |
277 | } |
278 | |
278 | |
279 | ... |
279 | ... |
280 | ev_set_allocator (persistent_realloc); |
280 | ev_set_allocator (persistent_realloc); |
281 | |
281 | |
282 | =item ev_set_syserr_cb (void (*cb)(const char *msg)); [NOT REENTRANT] |
282 | =item ev_set_syserr_cb (void (*cb)(const char *msg)) |
283 | |
283 | |
284 | Set the callback function to call on a retryable system call error (such |
284 | Set the callback function to call on a retryable system call error (such |
285 | as failed select, poll, epoll_wait). The message is a printable string |
285 | as failed select, poll, epoll_wait). The message is a printable string |
286 | indicating the system call or subsystem causing the problem. If this |
286 | indicating the system call or subsystem causing the problem. If this |
287 | callback is set, then libev will expect it to remedy the situation, no |
287 | callback is set, then libev will expect it to remedy the situation, no |
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402 | environment variable. |
402 | environment variable. |
403 | |
403 | |
404 | =item C<EVFLAG_NOINOTIFY> |
404 | =item C<EVFLAG_NOINOTIFY> |
405 | |
405 | |
406 | When this flag is specified, then libev will not attempt to use the |
406 | When this flag is specified, then libev will not attempt to use the |
407 | I<inotify> API for it's C<ev_stat> watchers. Apart from debugging and |
407 | I<inotify> API for its C<ev_stat> watchers. Apart from debugging and |
408 | testing, this flag can be useful to conserve inotify file descriptors, as |
408 | testing, this flag can be useful to conserve inotify file descriptors, as |
409 | otherwise each loop using C<ev_stat> watchers consumes one inotify handle. |
409 | otherwise each loop using C<ev_stat> watchers consumes one inotify handle. |
410 | |
410 | |
411 | =item C<EVFLAG_SIGNALFD> |
411 | =item C<EVFLAG_SIGNALFD> |
412 | |
412 | |
413 | When this flag is specified, then libev will attempt to use the |
413 | When this flag is specified, then libev will attempt to use the |
414 | I<signalfd> API for it's C<ev_signal> (and C<ev_child>) watchers. This API |
414 | I<signalfd> API for its C<ev_signal> (and C<ev_child>) watchers. This API |
415 | delivers signals synchronously, which makes it both faster and might make |
415 | delivers signals synchronously, which makes it both faster and might make |
416 | it possible to get the queued signal data. It can also simplify signal |
416 | it possible to get the queued signal data. It can also simplify signal |
417 | handling with threads, as long as you properly block signals in your |
417 | handling with threads, as long as you properly block signals in your |
418 | threads that are not interested in handling them. |
418 | threads that are not interested in handling them. |
419 | |
419 | |
… | |
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463 | epoll scales either O(1) or O(active_fds). |
463 | epoll scales either O(1) or O(active_fds). |
464 | |
464 | |
465 | The epoll mechanism deserves honorable mention as the most misdesigned |
465 | The epoll mechanism deserves honorable mention as the most misdesigned |
466 | of the more advanced event mechanisms: mere annoyances include silently |
466 | of the more advanced event mechanisms: mere annoyances include silently |
467 | dropping file descriptors, requiring a system call per change per file |
467 | dropping file descriptors, requiring a system call per change per file |
468 | descriptor (and unnecessary guessing of parameters), problems with dup and |
468 | descriptor (and unnecessary guessing of parameters), problems with dup, |
|
|
469 | returning before the timeout value, resulting in additional iterations |
|
|
470 | (and only giving 5ms accuracy while select on the same platform gives |
469 | so on. The biggest issue is fork races, however - if a program forks then |
471 | 0.1ms) and so on. The biggest issue is fork races, however - if a program |
470 | I<both> parent and child process have to recreate the epoll set, which can |
472 | forks then I<both> parent and child process have to recreate the epoll |
471 | take considerable time (one syscall per file descriptor) and is of course |
473 | set, which can take considerable time (one syscall per file descriptor) |
472 | hard to detect. |
474 | and is of course hard to detect. |
473 | |
475 | |
474 | Epoll is also notoriously buggy - embedding epoll fds I<should> work, but |
476 | Epoll is also notoriously buggy - embedding epoll fds I<should> work, but |
475 | of course I<doesn't>, and epoll just loves to report events for totally |
477 | of course I<doesn't>, and epoll just loves to report events for totally |
476 | I<different> file descriptors (even already closed ones, so one cannot |
478 | I<different> file descriptors (even already closed ones, so one cannot |
477 | even remove them from the set) than registered in the set (especially |
479 | even remove them from the set) than registered in the set (especially |
… | |
… | |
479 | employing an additional generation counter and comparing that against the |
481 | employing an additional generation counter and comparing that against the |
480 | events to filter out spurious ones, recreating the set when required. Last |
482 | events to filter out spurious ones, recreating the set when required. Last |
481 | not least, it also refuses to work with some file descriptors which work |
483 | not least, it also refuses to work with some file descriptors which work |
482 | perfectly fine with C<select> (files, many character devices...). |
484 | perfectly fine with C<select> (files, many character devices...). |
483 | |
485 | |
|
|
486 | Epoll is truly the train wreck analog among event poll mechanisms. |
|
|
487 | |
484 | While stopping, setting and starting an I/O watcher in the same iteration |
488 | While stopping, setting and starting an I/O watcher in the same iteration |
485 | will result in some caching, there is still a system call per such |
489 | will result in some caching, there is still a system call per such |
486 | incident (because the same I<file descriptor> could point to a different |
490 | incident (because the same I<file descriptor> could point to a different |
487 | I<file description> now), so its best to avoid that. Also, C<dup ()>'ed |
491 | I<file description> now), so its best to avoid that. Also, C<dup ()>'ed |
488 | file descriptors might not work very well if you register events for both |
492 | file descriptors might not work very well if you register events for both |
… | |
… | |
615 | This function is normally used on loop objects allocated by |
619 | This function is normally used on loop objects allocated by |
616 | C<ev_loop_new>, but it can also be used on the default loop returned by |
620 | C<ev_loop_new>, but it can also be used on the default loop returned by |
617 | C<ev_default_loop>, in which case it is not thread-safe. |
621 | C<ev_default_loop>, in which case it is not thread-safe. |
618 | |
622 | |
619 | Note that it is not advisable to call this function on the default loop |
623 | Note that it is not advisable to call this function on the default loop |
620 | except in the rare occasion where you really need to free it's resources. |
624 | except in the rare occasion where you really need to free its resources. |
621 | If you need dynamically allocated loops it is better to use C<ev_loop_new> |
625 | If you need dynamically allocated loops it is better to use C<ev_loop_new> |
622 | and C<ev_loop_destroy>. |
626 | and C<ev_loop_destroy>. |
623 | |
627 | |
624 | =item ev_loop_fork (loop) |
628 | =item ev_loop_fork (loop) |
625 | |
629 | |
… | |
… | |
823 | Can be used to make a call to C<ev_run> return early (but only after it |
827 | Can be used to make a call to C<ev_run> return early (but only after it |
824 | has processed all outstanding events). The C<how> argument must be either |
828 | has processed all outstanding events). The C<how> argument must be either |
825 | C<EVBREAK_ONE>, which will make the innermost C<ev_run> call return, or |
829 | C<EVBREAK_ONE>, which will make the innermost C<ev_run> call return, or |
826 | C<EVBREAK_ALL>, which will make all nested C<ev_run> calls return. |
830 | C<EVBREAK_ALL>, which will make all nested C<ev_run> calls return. |
827 | |
831 | |
828 | This "unloop state" will be cleared when entering C<ev_run> again. |
832 | This "break state" will be cleared when entering C<ev_run> again. |
829 | |
833 | |
830 | It is safe to call C<ev_break> from outside any C<ev_run> calls. ##TODO## |
834 | It is safe to call C<ev_break> from outside any C<ev_run> calls, too. |
831 | |
835 | |
832 | =item ev_ref (loop) |
836 | =item ev_ref (loop) |
833 | |
837 | |
834 | =item ev_unref (loop) |
838 | =item ev_unref (loop) |
835 | |
839 | |
… | |
… | |
2256 | |
2260 | |
2257 | =head2 C<ev_signal> - signal me when a signal gets signalled! |
2261 | =head2 C<ev_signal> - signal me when a signal gets signalled! |
2258 | |
2262 | |
2259 | Signal watchers will trigger an event when the process receives a specific |
2263 | Signal watchers will trigger an event when the process receives a specific |
2260 | signal one or more times. Even though signals are very asynchronous, libev |
2264 | signal one or more times. Even though signals are very asynchronous, libev |
2261 | will try it's best to deliver signals synchronously, i.e. as part of the |
2265 | will try its best to deliver signals synchronously, i.e. as part of the |
2262 | normal event processing, like any other event. |
2266 | normal event processing, like any other event. |
2263 | |
2267 | |
2264 | If you want signals to be delivered truly asynchronously, just use |
2268 | If you want signals to be delivered truly asynchronously, just use |
2265 | C<sigaction> as you would do without libev and forget about sharing |
2269 | C<sigaction> as you would do without libev and forget about sharing |
2266 | the signal. You can even use C<ev_async> from a signal handler to |
2270 | the signal. You can even use C<ev_async> from a signal handler to |