… | |
… | |
355 | =item struct ev_loop *ev_loop_new (unsigned int flags) |
355 | =item struct ev_loop *ev_loop_new (unsigned int flags) |
356 | |
356 | |
357 | This will create and initialise a new event loop object. If the loop |
357 | This will create and initialise a new event loop object. If the loop |
358 | could not be initialised, returns false. |
358 | could not be initialised, returns false. |
359 | |
359 | |
360 | Note that this function I<is> thread-safe, and one common way to use |
360 | This function is thread-safe, and one common way to use libev with |
361 | libev with threads is indeed to create one loop per thread, and using the |
361 | threads is indeed to create one loop per thread, and using the default |
362 | default loop in the "main" or "initial" thread. |
362 | loop in the "main" or "initial" thread. |
363 | |
363 | |
364 | The flags argument can be used to specify special behaviour or specific |
364 | The flags argument can be used to specify special behaviour or specific |
365 | backends to use, and is usually specified as C<0> (or C<EVFLAG_AUTO>). |
365 | backends to use, and is usually specified as C<0> (or C<EVFLAG_AUTO>). |
366 | |
366 | |
367 | The following flags are supported: |
367 | The following flags are supported: |
… | |
… | |
677 | prepare and check phases. |
677 | prepare and check phases. |
678 | |
678 | |
679 | =item unsigned int ev_depth (loop) |
679 | =item unsigned int ev_depth (loop) |
680 | |
680 | |
681 | Returns the number of times C<ev_run> was entered minus the number of |
681 | Returns the number of times C<ev_run> was entered minus the number of |
682 | times C<ev_run> was exited, in other words, the recursion depth. |
682 | times C<ev_run> was exited normally, in other words, the recursion depth. |
683 | |
683 | |
684 | Outside C<ev_run>, this number is zero. In a callback, this number is |
684 | Outside C<ev_run>, this number is zero. In a callback, this number is |
685 | C<1>, unless C<ev_run> was invoked recursively (or from another thread), |
685 | C<1>, unless C<ev_run> was invoked recursively (or from another thread), |
686 | in which case it is higher. |
686 | in which case it is higher. |
687 | |
687 | |
688 | Leaving C<ev_run> abnormally (setjmp/longjmp, cancelling the thread |
688 | Leaving C<ev_run> abnormally (setjmp/longjmp, cancelling the thread, |
689 | etc.), doesn't count as "exit" - consider this as a hint to avoid such |
689 | throwing an exception etc.), doesn't count as "exit" - consider this |
690 | ungentleman-like behaviour unless it's really convenient. |
690 | as a hint to avoid such ungentleman-like behaviour unless it's really |
|
|
691 | convenient, in which case it is fully supported. |
691 | |
692 | |
692 | =item unsigned int ev_backend (loop) |
693 | =item unsigned int ev_backend (loop) |
693 | |
694 | |
694 | Returns one of the C<EVBACKEND_*> flags indicating the event backend in |
695 | Returns one of the C<EVBACKEND_*> flags indicating the event backend in |
695 | use. |
696 | use. |
… | |
… | |
756 | relying on all watchers to be stopped when deciding when a program has |
757 | relying on all watchers to be stopped when deciding when a program has |
757 | finished (especially in interactive programs), but having a program |
758 | finished (especially in interactive programs), but having a program |
758 | that automatically loops as long as it has to and no longer by virtue |
759 | that automatically loops as long as it has to and no longer by virtue |
759 | of relying on its watchers stopping correctly, that is truly a thing of |
760 | of relying on its watchers stopping correctly, that is truly a thing of |
760 | beauty. |
761 | beauty. |
|
|
762 | |
|
|
763 | This function is also I<mostly> exception-safe - you can break out of |
|
|
764 | a C<ev_run> call by calling C<longjmp> in a callback, throwing a C++ |
|
|
765 | exception and so on. This does not decrement the C<ev_depth> value, nor |
|
|
766 | will it clear any outstanding C<EVBREAK_ONE> breaks. |
761 | |
767 | |
762 | A flags value of C<EVRUN_NOWAIT> will look for new events, will handle |
768 | A flags value of C<EVRUN_NOWAIT> will look for new events, will handle |
763 | those events and any already outstanding ones, but will not wait and |
769 | those events and any already outstanding ones, but will not wait and |
764 | block your process in case there are no events and will return after one |
770 | block your process in case there are no events and will return after one |
765 | iteration of the loop. This is sometimes useful to poll and handle new |
771 | iteration of the loop. This is sometimes useful to poll and handle new |
… | |
… | |
827 | Can be used to make a call to C<ev_run> return early (but only after it |
833 | Can be used to make a call to C<ev_run> return early (but only after it |
828 | has processed all outstanding events). The C<how> argument must be either |
834 | has processed all outstanding events). The C<how> argument must be either |
829 | C<EVBREAK_ONE>, which will make the innermost C<ev_run> call return, or |
835 | C<EVBREAK_ONE>, which will make the innermost C<ev_run> call return, or |
830 | C<EVBREAK_ALL>, which will make all nested C<ev_run> calls return. |
836 | C<EVBREAK_ALL>, which will make all nested C<ev_run> calls return. |
831 | |
837 | |
832 | This "break state" will be cleared when entering C<ev_run> again. |
838 | This "break state" will be cleared on the next call to C<ev_run>. |
833 | |
839 | |
834 | It is safe to call C<ev_break> from outside any C<ev_run> calls, too. |
840 | It is safe to call C<ev_break> from outside any C<ev_run> calls, too, in |
|
|
841 | which case it will have no effect. |
835 | |
842 | |
836 | =item ev_ref (loop) |
843 | =item ev_ref (loop) |
837 | |
844 | |
838 | =item ev_unref (loop) |
845 | =item ev_unref (loop) |
839 | |
846 | |
… | |
… | |
982 | See also the locking example in the C<THREADS> section later in this |
989 | See also the locking example in the C<THREADS> section later in this |
983 | document. |
990 | document. |
984 | |
991 | |
985 | =item ev_set_userdata (loop, void *data) |
992 | =item ev_set_userdata (loop, void *data) |
986 | |
993 | |
987 | =item ev_userdata (loop) |
994 | =item void *ev_userdata (loop) |
988 | |
995 | |
989 | Set and retrieve a single C<void *> associated with a loop. When |
996 | Set and retrieve a single C<void *> associated with a loop. When |
990 | C<ev_set_userdata> has never been called, then C<ev_userdata> returns |
997 | C<ev_set_userdata> has never been called, then C<ev_userdata> returns |
991 | C<0.> |
998 | C<0>. |
992 | |
999 | |
993 | These two functions can be used to associate arbitrary data with a loop, |
1000 | These two functions can be used to associate arbitrary data with a loop, |
994 | and are intended solely for the C<invoke_pending_cb>, C<release> and |
1001 | and are intended solely for the C<invoke_pending_cb>, C<release> and |
995 | C<acquire> callbacks described above, but of course can be (ab-)used for |
1002 | C<acquire> callbacks described above, but of course can be (ab-)used for |
996 | any other purpose as well. |
1003 | any other purpose as well. |
… | |
… | |
3360 | loop!). |
3367 | loop!). |
3361 | |
3368 | |
3362 | =back |
3369 | =back |
3363 | |
3370 | |
3364 | |
3371 | |
|
|
3372 | =head1 COMMON OR USEFUL IDIOMS (OR BOTH) |
|
|
3373 | |
|
|
3374 | This section explains some common idioms that are not immediately |
|
|
3375 | obvious. Note that examples are sprinkled over the whole manual, and this |
|
|
3376 | section only contains stuff that wouldn't fit anywhere else. |
|
|
3377 | |
|
|
3378 | =over 4 |
|
|
3379 | |
|
|
3380 | =item Model/nested event loop invocations and exit conditions. |
|
|
3381 | |
|
|
3382 | Often (especially in GUI toolkits) there are places where you have |
|
|
3383 | I<modal> interaction, which is most easily implemented by recursively |
|
|
3384 | invoking C<ev_run>. |
|
|
3385 | |
|
|
3386 | This brings the problem of exiting - a callback might want to finish the |
|
|
3387 | main C<ev_run> call, but not the nested one (e.g. user clicked "Quit", but |
|
|
3388 | a modal "Are you sure?" dialog is still waiting), or just the nested one |
|
|
3389 | and not the main one (e.g. user clocked "Ok" in a modal dialog), or some |
|
|
3390 | other combination: In these cases, C<ev_break> will not work alone. |
|
|
3391 | |
|
|
3392 | The solution is to maintain "break this loop" variable for each C<ev_run> |
|
|
3393 | invocation, and use a loop around C<ev_run> until the condition is |
|
|
3394 | triggered, using C<EVRUN_ONCE>: |
|
|
3395 | |
|
|
3396 | // main loop |
|
|
3397 | int exit_main_loop = 0; |
|
|
3398 | |
|
|
3399 | while (!exit_main_loop) |
|
|
3400 | ev_run (EV_DEFAULT_ EVRUN_ONCE); |
|
|
3401 | |
|
|
3402 | // in a model watcher |
|
|
3403 | int exit_nested_loop = 0; |
|
|
3404 | |
|
|
3405 | while (!exit_nested_loop) |
|
|
3406 | ev_run (EV_A_ EVRUN_ONCE); |
|
|
3407 | |
|
|
3408 | To exit from any of these loops, just set the corresponding exit variable: |
|
|
3409 | |
|
|
3410 | // exit modal loop |
|
|
3411 | exit_nested_loop = 1; |
|
|
3412 | |
|
|
3413 | // exit main program, after modal loop is finished |
|
|
3414 | exit_main_loop = 1; |
|
|
3415 | |
|
|
3416 | // exit both |
|
|
3417 | exit_main_loop = exit_nested_loop = 1; |
|
|
3418 | |
|
|
3419 | =back |
|
|
3420 | |
|
|
3421 | |
3365 | =head1 LIBEVENT EMULATION |
3422 | =head1 LIBEVENT EMULATION |
3366 | |
3423 | |
3367 | Libev offers a compatibility emulation layer for libevent. It cannot |
3424 | Libev offers a compatibility emulation layer for libevent. It cannot |
3368 | emulate the internals of libevent, so here are some usage hints: |
3425 | emulate the internals of libevent, so here are some usage hints: |
3369 | |
3426 | |
3370 | =over 4 |
3427 | =over 4 |
|
|
3428 | |
|
|
3429 | =item * Only the libevent-1.4.1-beta API is being emulated. |
|
|
3430 | |
|
|
3431 | This was the newest libevent version available when libev was implemented, |
|
|
3432 | and is still mostly uncanged in 2010. |
3371 | |
3433 | |
3372 | =item * Use it by including <event.h>, as usual. |
3434 | =item * Use it by including <event.h>, as usual. |
3373 | |
3435 | |
3374 | =item * The following members are fully supported: ev_base, ev_callback, |
3436 | =item * The following members are fully supported: ev_base, ev_callback, |
3375 | ev_arg, ev_fd, ev_res, ev_events. |
3437 | ev_arg, ev_fd, ev_res, ev_events. |
… | |
… | |
3381 | =item * Priorities are not currently supported. Initialising priorities |
3443 | =item * Priorities are not currently supported. Initialising priorities |
3382 | will fail and all watchers will have the same priority, even though there |
3444 | will fail and all watchers will have the same priority, even though there |
3383 | is an ev_pri field. |
3445 | is an ev_pri field. |
3384 | |
3446 | |
3385 | =item * In libevent, the last base created gets the signals, in libev, the |
3447 | =item * In libevent, the last base created gets the signals, in libev, the |
3386 | first base created (== the default loop) gets the signals. |
3448 | base that registered the signal gets the signals. |
3387 | |
3449 | |
3388 | =item * Other members are not supported. |
3450 | =item * Other members are not supported. |
3389 | |
3451 | |
3390 | =item * The libev emulation is I<not> ABI compatible to libevent, you need |
3452 | =item * The libev emulation is I<not> ABI compatible to libevent, you need |
3391 | to use the libev header file and library. |
3453 | to use the libev header file and library. |
… | |
… | |
3410 | Care has been taken to keep the overhead low. The only data member the C++ |
3472 | Care has been taken to keep the overhead low. The only data member the C++ |
3411 | classes add (compared to plain C-style watchers) is the event loop pointer |
3473 | classes add (compared to plain C-style watchers) is the event loop pointer |
3412 | that the watcher is associated with (or no additional members at all if |
3474 | that the watcher is associated with (or no additional members at all if |
3413 | you disable C<EV_MULTIPLICITY> when embedding libev). |
3475 | you disable C<EV_MULTIPLICITY> when embedding libev). |
3414 | |
3476 | |
3415 | Currently, functions, and static and non-static member functions can be |
3477 | Currently, functions, static and non-static member functions and classes |
3416 | used as callbacks. Other types should be easy to add as long as they only |
3478 | with C<operator ()> can be used as callbacks. Other types should be easy |
3417 | need one additional pointer for context. If you need support for other |
3479 | to add as long as they only need one additional pointer for context. If |
3418 | types of functors please contact the author (preferably after implementing |
3480 | you need support for other types of functors please contact the author |
3419 | it). |
3481 | (preferably after implementing it). |
3420 | |
3482 | |
3421 | Here is a list of things available in the C<ev> namespace: |
3483 | Here is a list of things available in the C<ev> namespace: |
3422 | |
3484 | |
3423 | =over 4 |
3485 | =over 4 |
3424 | |
3486 | |