… | |
… | |
106 | returned by C<ev_supported_backends>, as for example kqueue is broken on |
106 | returned by C<ev_supported_backends>, as for example kqueue is broken on |
107 | most BSDs and will not be autodetected unless you explicitly request it |
107 | most BSDs and will not be autodetected unless you explicitly request it |
108 | (assuming you know what you are doing). This is the set of backends that |
108 | (assuming you know what you are doing). This is the set of backends that |
109 | libev will probe for if you specify no backends explicitly. |
109 | libev will probe for if you specify no backends explicitly. |
110 | |
110 | |
|
|
111 | =item unsigned int ev_embeddable_backends () |
|
|
112 | |
|
|
113 | Returns the set of backends that are embeddable in other event loops. This |
|
|
114 | is the theoretical, all-platform, value. To find which backends |
|
|
115 | might be supported on the current system, you would need to look at |
|
|
116 | C<ev_embeddable_backends () & ev_supported_backends ()>, likewise for |
|
|
117 | recommended ones. |
|
|
118 | |
|
|
119 | See the description of C<ev_embed> watchers for more info. |
|
|
120 | |
111 | =item ev_set_allocator (void *(*cb)(void *ptr, long size)) |
121 | =item ev_set_allocator (void *(*cb)(void *ptr, long size)) |
112 | |
122 | |
113 | Sets the allocation function to use (the prototype is similar to the |
123 | Sets the allocation function to use (the prototype is similar to the |
114 | realloc C function, the semantics are identical). It is used to allocate |
124 | realloc C function, the semantics are identical). It is used to allocate |
115 | and free memory (no surprises here). If it returns zero when memory |
125 | and free memory (no surprises here). If it returns zero when memory |
… | |
… | |
313 | fatal ("no epoll found here, maybe it hides under your chair"); |
323 | fatal ("no epoll found here, maybe it hides under your chair"); |
314 | |
324 | |
315 | =item ev_default_destroy () |
325 | =item ev_default_destroy () |
316 | |
326 | |
317 | Destroys the default loop again (frees all memory and kernel state |
327 | Destroys the default loop again (frees all memory and kernel state |
318 | etc.). This stops all registered event watchers (by not touching them in |
328 | etc.). None of the active event watchers will be stopped in the normal |
319 | any way whatsoever, although you cannot rely on this :). |
329 | sense, so e.g. C<ev_is_active> might still return true. It is your |
|
|
330 | responsibility to either stop all watchers cleanly yoursef I<before> |
|
|
331 | calling this function, or cope with the fact afterwards (which is usually |
|
|
332 | the easiest thing, youc na just ignore the watchers and/or C<free ()> them |
|
|
333 | for example). |
320 | |
334 | |
321 | =item ev_loop_destroy (loop) |
335 | =item ev_loop_destroy (loop) |
322 | |
336 | |
323 | Like C<ev_default_destroy>, but destroys an event loop created by an |
337 | Like C<ev_default_destroy>, but destroys an event loop created by an |
324 | earlier call to C<ev_loop_new>. |
338 | earlier call to C<ev_loop_new>. |
… | |
… | |
454 | ev_ref (myloop); |
468 | ev_ref (myloop); |
455 | ev_signal_stop (myloop, &exitsig); |
469 | ev_signal_stop (myloop, &exitsig); |
456 | |
470 | |
457 | =back |
471 | =back |
458 | |
472 | |
|
|
473 | |
459 | =head1 ANATOMY OF A WATCHER |
474 | =head1 ANATOMY OF A WATCHER |
460 | |
475 | |
461 | A watcher is a structure that you create and register to record your |
476 | A watcher is a structure that you create and register to record your |
462 | interest in some event. For instance, if you want to wait for STDIN to |
477 | interest in some event. For instance, if you want to wait for STDIN to |
463 | become readable, you would create an C<ev_io> watcher for that: |
478 | become readable, you would create an C<ev_io> watcher for that: |
… | |
… | |
495 | *) >>), and you can stop watching for events at any time by calling the |
510 | *) >>), and you can stop watching for events at any time by calling the |
496 | corresponding stop function (C<< ev_<type>_stop (loop, watcher *) >>. |
511 | corresponding stop function (C<< ev_<type>_stop (loop, watcher *) >>. |
497 | |
512 | |
498 | As long as your watcher is active (has been started but not stopped) you |
513 | As long as your watcher is active (has been started but not stopped) you |
499 | must not touch the values stored in it. Most specifically you must never |
514 | must not touch the values stored in it. Most specifically you must never |
500 | reinitialise it or call its set macro. |
515 | reinitialise it or call its C<set> macro. |
501 | |
|
|
502 | You can check whether an event is active by calling the C<ev_is_active |
|
|
503 | (watcher *)> macro. To see whether an event is outstanding (but the |
|
|
504 | callback for it has not been called yet) you can use the C<ev_is_pending |
|
|
505 | (watcher *)> macro. |
|
|
506 | |
516 | |
507 | Each and every callback receives the event loop pointer as first, the |
517 | Each and every callback receives the event loop pointer as first, the |
508 | registered watcher structure as second, and a bitset of received events as |
518 | registered watcher structure as second, and a bitset of received events as |
509 | third argument. |
519 | third argument. |
510 | |
520 | |
… | |
… | |
567 | with the error from read() or write(). This will not work in multithreaded |
577 | with the error from read() or write(). This will not work in multithreaded |
568 | programs, though, so beware. |
578 | programs, though, so beware. |
569 | |
579 | |
570 | =back |
580 | =back |
571 | |
581 | |
|
|
582 | =head2 GENERIC WATCHER FUNCTIONS |
|
|
583 | |
|
|
584 | In the following description, C<TYPE> stands for the watcher type, |
|
|
585 | e.g. C<timer> for C<ev_timer> watchers and C<io> for C<ev_io> watchers. |
|
|
586 | |
|
|
587 | =over 4 |
|
|
588 | |
|
|
589 | =item C<ev_init> (ev_TYPE *watcher, callback) |
|
|
590 | |
|
|
591 | This macro initialises the generic portion of a watcher. The contents |
|
|
592 | of the watcher object can be arbitrary (so C<malloc> will do). Only |
|
|
593 | the generic parts of the watcher are initialised, you I<need> to call |
|
|
594 | the type-specific C<ev_TYPE_set> macro afterwards to initialise the |
|
|
595 | type-specific parts. For each type there is also a C<ev_TYPE_init> macro |
|
|
596 | which rolls both calls into one. |
|
|
597 | |
|
|
598 | You can reinitialise a watcher at any time as long as it has been stopped |
|
|
599 | (or never started) and there are no pending events outstanding. |
|
|
600 | |
|
|
601 | The callback is always of type C<void (*)(ev_loop *loop, ev_TYPE *watcher, |
|
|
602 | int revents)>. |
|
|
603 | |
|
|
604 | =item C<ev_TYPE_set> (ev_TYPE *, [args]) |
|
|
605 | |
|
|
606 | This macro initialises the type-specific parts of a watcher. You need to |
|
|
607 | call C<ev_init> at least once before you call this macro, but you can |
|
|
608 | call C<ev_TYPE_set> any number of times. You must not, however, call this |
|
|
609 | macro on a watcher that is active (it can be pending, however, which is a |
|
|
610 | difference to the C<ev_init> macro). |
|
|
611 | |
|
|
612 | Although some watcher types do not have type-specific arguments |
|
|
613 | (e.g. C<ev_prepare>) you still need to call its C<set> macro. |
|
|
614 | |
|
|
615 | =item C<ev_TYPE_init> (ev_TYPE *watcher, callback, [args]) |
|
|
616 | |
|
|
617 | This convinience macro rolls both C<ev_init> and C<ev_TYPE_set> macro |
|
|
618 | calls into a single call. This is the most convinient method to initialise |
|
|
619 | a watcher. The same limitations apply, of course. |
|
|
620 | |
|
|
621 | =item C<ev_TYPE_start> (loop *, ev_TYPE *watcher) |
|
|
622 | |
|
|
623 | Starts (activates) the given watcher. Only active watchers will receive |
|
|
624 | events. If the watcher is already active nothing will happen. |
|
|
625 | |
|
|
626 | =item C<ev_TYPE_stop> (loop *, ev_TYPE *watcher) |
|
|
627 | |
|
|
628 | Stops the given watcher again (if active) and clears the pending |
|
|
629 | status. It is possible that stopped watchers are pending (for example, |
|
|
630 | non-repeating timers are being stopped when they become pending), but |
|
|
631 | C<ev_TYPE_stop> ensures that the watcher is neither active nor pending. If |
|
|
632 | you want to free or reuse the memory used by the watcher it is therefore a |
|
|
633 | good idea to always call its C<ev_TYPE_stop> function. |
|
|
634 | |
|
|
635 | =item bool ev_is_active (ev_TYPE *watcher) |
|
|
636 | |
|
|
637 | Returns a true value iff the watcher is active (i.e. it has been started |
|
|
638 | and not yet been stopped). As long as a watcher is active you must not modify |
|
|
639 | it. |
|
|
640 | |
|
|
641 | =item bool ev_is_pending (ev_TYPE *watcher) |
|
|
642 | |
|
|
643 | Returns a true value iff the watcher is pending, (i.e. it has outstanding |
|
|
644 | events but its callback has not yet been invoked). As long as a watcher |
|
|
645 | is pending (but not active) you must not call an init function on it (but |
|
|
646 | C<ev_TYPE_set> is safe) and you must make sure the watcher is available to |
|
|
647 | libev (e.g. you cnanot C<free ()> it). |
|
|
648 | |
|
|
649 | =item callback = ev_cb (ev_TYPE *watcher) |
|
|
650 | |
|
|
651 | Returns the callback currently set on the watcher. |
|
|
652 | |
|
|
653 | =item ev_cb_set (ev_TYPE *watcher, callback) |
|
|
654 | |
|
|
655 | Change the callback. You can change the callback at virtually any time |
|
|
656 | (modulo threads). |
|
|
657 | |
|
|
658 | =back |
|
|
659 | |
|
|
660 | |
572 | =head2 ASSOCIATING CUSTOM DATA WITH A WATCHER |
661 | =head2 ASSOCIATING CUSTOM DATA WITH A WATCHER |
573 | |
662 | |
574 | Each watcher has, by default, a member C<void *data> that you can change |
663 | Each watcher has, by default, a member C<void *data> that you can change |
575 | and read at any time, libev will completely ignore it. This can be used |
664 | and read at any time, libev will completely ignore it. This can be used |
576 | to associate arbitrary data with your watcher. If you need more data and |
665 | to associate arbitrary data with your watcher. If you need more data and |
… | |
… | |
603 | |
692 | |
604 | This section describes each watcher in detail, but will not repeat |
693 | This section describes each watcher in detail, but will not repeat |
605 | information given in the last section. |
694 | information given in the last section. |
606 | |
695 | |
607 | |
696 | |
608 | =head2 C<ev_io> - is this file descriptor readable or writable |
697 | =head2 C<ev_io> - is this file descriptor readable or writable? |
609 | |
698 | |
610 | I/O watchers check whether a file descriptor is readable or writable |
699 | I/O watchers check whether a file descriptor is readable or writable |
611 | in each iteration of the event loop (This behaviour is called |
700 | in each iteration of the event loop, or, more precisely, when reading |
612 | level-triggering because you keep receiving events as long as the |
701 | would not block the process and writing would at least be able to write |
613 | condition persists. Remember you can stop the watcher if you don't want to |
702 | some data. This behaviour is called level-triggering because you keep |
614 | act on the event and neither want to receive future events). |
703 | receiving events as long as the condition persists. Remember you can stop |
|
|
704 | the watcher if you don't want to act on the event and neither want to |
|
|
705 | receive future events. |
615 | |
706 | |
616 | In general you can register as many read and/or write event watchers per |
707 | In general you can register as many read and/or write event watchers per |
617 | fd as you want (as long as you don't confuse yourself). Setting all file |
708 | fd as you want (as long as you don't confuse yourself). Setting all file |
618 | descriptors to non-blocking mode is also usually a good idea (but not |
709 | descriptors to non-blocking mode is also usually a good idea (but not |
619 | required if you know what you are doing). |
710 | required if you know what you are doing). |
620 | |
711 | |
621 | You have to be careful with dup'ed file descriptors, though. Some backends |
712 | You have to be careful with dup'ed file descriptors, though. Some backends |
622 | (the linux epoll backend is a notable example) cannot handle dup'ed file |
713 | (the linux epoll backend is a notable example) cannot handle dup'ed file |
623 | descriptors correctly if you register interest in two or more fds pointing |
714 | descriptors correctly if you register interest in two or more fds pointing |
624 | to the same underlying file/socket etc. description (that is, they share |
715 | to the same underlying file/socket/etc. description (that is, they share |
625 | the same underlying "file open"). |
716 | the same underlying "file open"). |
626 | |
717 | |
627 | If you must do this, then force the use of a known-to-be-good backend |
718 | If you must do this, then force the use of a known-to-be-good backend |
628 | (at the time of this writing, this includes only C<EVBACKEND_SELECT> and |
719 | (at the time of this writing, this includes only C<EVBACKEND_SELECT> and |
629 | C<EVBACKEND_POLL>). |
720 | C<EVBACKEND_POLL>). |
630 | |
721 | |
|
|
722 | Another thing you have to watch out for is that it is quite easy to |
|
|
723 | receive "spurious" readyness notifications, that is your callback might |
|
|
724 | be called with C<EV_READ> but a subsequent C<read>(2) will actually block |
|
|
725 | because there is no data. Not only are some backends known to create a |
|
|
726 | lot of those (for example solaris ports), it is very easy to get into |
|
|
727 | this situation even with a relatively standard program structure. Thus |
|
|
728 | it is best to always use non-blocking I/O: An extra C<read>(2) returning |
|
|
729 | C<EAGAIN> is far preferable to a program hanging until some data arrives. |
|
|
730 | |
|
|
731 | If you cannot run the fd in non-blocking mode (for example you should not |
|
|
732 | play around with an Xlib connection), then you have to seperately re-test |
|
|
733 | wether a file descriptor is really ready with a known-to-be good interface |
|
|
734 | such as poll (fortunately in our Xlib example, Xlib already does this on |
|
|
735 | its own, so its quite safe to use). |
|
|
736 | |
631 | =over 4 |
737 | =over 4 |
632 | |
738 | |
633 | =item ev_io_init (ev_io *, callback, int fd, int events) |
739 | =item ev_io_init (ev_io *, callback, int fd, int events) |
634 | |
740 | |
635 | =item ev_io_set (ev_io *, int fd, int events) |
741 | =item ev_io_set (ev_io *, int fd, int events) |
636 | |
742 | |
637 | Configures an C<ev_io> watcher. The fd is the file descriptor to rceeive |
743 | Configures an C<ev_io> watcher. The C<fd> is the file descriptor to |
638 | events for and events is either C<EV_READ>, C<EV_WRITE> or C<EV_READ | |
744 | rceeive events for and events is either C<EV_READ>, C<EV_WRITE> or |
639 | EV_WRITE> to receive the given events. |
745 | C<EV_READ | EV_WRITE> to receive the given events. |
640 | |
|
|
641 | Please note that most of the more scalable backend mechanisms (for example |
|
|
642 | epoll and solaris ports) can result in spurious readyness notifications |
|
|
643 | for file descriptors, so you practically need to use non-blocking I/O (and |
|
|
644 | treat callback invocation as hint only), or retest separately with a safe |
|
|
645 | interface before doing I/O (XLib can do this), or force the use of either |
|
|
646 | C<EVBACKEND_SELECT> or C<EVBACKEND_POLL>, which don't suffer from this |
|
|
647 | problem. Also note that it is quite easy to have your callback invoked |
|
|
648 | when the readyness condition is no longer valid even when employing |
|
|
649 | typical ways of handling events, so its a good idea to use non-blocking |
|
|
650 | I/O unconditionally. |
|
|
651 | |
746 | |
652 | =back |
747 | =back |
653 | |
748 | |
654 | Example: call C<stdin_readable_cb> when STDIN_FILENO has become, well |
749 | Example: call C<stdin_readable_cb> when STDIN_FILENO has become, well |
655 | readable, but only once. Since it is likely line-buffered, you could |
750 | readable, but only once. Since it is likely line-buffered, you could |
… | |
… | |
668 | ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ); |
763 | ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ); |
669 | ev_io_start (loop, &stdin_readable); |
764 | ev_io_start (loop, &stdin_readable); |
670 | ev_loop (loop, 0); |
765 | ev_loop (loop, 0); |
671 | |
766 | |
672 | |
767 | |
673 | =head2 C<ev_timer> - relative and optionally recurring timeouts |
768 | =head2 C<ev_timer> - relative and optionally repeating timeouts |
674 | |
769 | |
675 | Timer watchers are simple relative timers that generate an event after a |
770 | Timer watchers are simple relative timers that generate an event after a |
676 | given time, and optionally repeating in regular intervals after that. |
771 | given time, and optionally repeating in regular intervals after that. |
677 | |
772 | |
678 | The timers are based on real time, that is, if you register an event that |
773 | The timers are based on real time, that is, if you register an event that |
… | |
… | |
760 | // and in some piece of code that gets executed on any "activity": |
855 | // and in some piece of code that gets executed on any "activity": |
761 | // reset the timeout to start ticking again at 10 seconds |
856 | // reset the timeout to start ticking again at 10 seconds |
762 | ev_timer_again (&mytimer); |
857 | ev_timer_again (&mytimer); |
763 | |
858 | |
764 | |
859 | |
765 | =head2 C<ev_periodic> - to cron or not to cron |
860 | =head2 C<ev_periodic> - to cron or not to cron? |
766 | |
861 | |
767 | Periodic watchers are also timers of a kind, but they are very versatile |
862 | Periodic watchers are also timers of a kind, but they are very versatile |
768 | (and unfortunately a bit complex). |
863 | (and unfortunately a bit complex). |
769 | |
864 | |
770 | Unlike C<ev_timer>'s, they are not based on real time (or relative time) |
865 | Unlike C<ev_timer>'s, they are not based on real time (or relative time) |
771 | but on wallclock time (absolute time). You can tell a periodic watcher |
866 | but on wallclock time (absolute time). You can tell a periodic watcher |
772 | to trigger "at" some specific point in time. For example, if you tell a |
867 | to trigger "at" some specific point in time. For example, if you tell a |
773 | periodic watcher to trigger in 10 seconds (by specifiying e.g. c<ev_now () |
868 | periodic watcher to trigger in 10 seconds (by specifiying e.g. C<ev_now () |
774 | + 10.>) and then reset your system clock to the last year, then it will |
869 | + 10.>) and then reset your system clock to the last year, then it will |
775 | take a year to trigger the event (unlike an C<ev_timer>, which would trigger |
870 | take a year to trigger the event (unlike an C<ev_timer>, which would trigger |
776 | roughly 10 seconds later and of course not if you reset your system time |
871 | roughly 10 seconds later and of course not if you reset your system time |
777 | again). |
872 | again). |
778 | |
873 | |
… | |
… | |
898 | ev_periodic_init (&hourly_tick, clock_cb, |
993 | ev_periodic_init (&hourly_tick, clock_cb, |
899 | fmod (ev_now (loop), 3600.), 3600., 0); |
994 | fmod (ev_now (loop), 3600.), 3600., 0); |
900 | ev_periodic_start (loop, &hourly_tick); |
995 | ev_periodic_start (loop, &hourly_tick); |
901 | |
996 | |
902 | |
997 | |
903 | =head2 C<ev_signal> - signal me when a signal gets signalled |
998 | =head2 C<ev_signal> - signal me when a signal gets signalled! |
904 | |
999 | |
905 | Signal watchers will trigger an event when the process receives a specific |
1000 | Signal watchers will trigger an event when the process receives a specific |
906 | signal one or more times. Even though signals are very asynchronous, libev |
1001 | signal one or more times. Even though signals are very asynchronous, libev |
907 | will try it's best to deliver signals synchronously, i.e. as part of the |
1002 | will try it's best to deliver signals synchronously, i.e. as part of the |
908 | normal event processing, like any other event. |
1003 | normal event processing, like any other event. |
… | |
… | |
923 | Configures the watcher to trigger on the given signal number (usually one |
1018 | Configures the watcher to trigger on the given signal number (usually one |
924 | of the C<SIGxxx> constants). |
1019 | of the C<SIGxxx> constants). |
925 | |
1020 | |
926 | =back |
1021 | =back |
927 | |
1022 | |
|
|
1023 | |
928 | =head2 C<ev_child> - wait for pid status changes |
1024 | =head2 C<ev_child> - watch out for process status changes |
929 | |
1025 | |
930 | Child watchers trigger when your process receives a SIGCHLD in response to |
1026 | Child watchers trigger when your process receives a SIGCHLD in response to |
931 | some child status changes (most typically when a child of yours dies). |
1027 | some child status changes (most typically when a child of yours dies). |
932 | |
1028 | |
933 | =over 4 |
1029 | =over 4 |
… | |
… | |
956 | struct ev_signal signal_watcher; |
1052 | struct ev_signal signal_watcher; |
957 | ev_signal_init (&signal_watcher, sigint_cb, SIGINT); |
1053 | ev_signal_init (&signal_watcher, sigint_cb, SIGINT); |
958 | ev_signal_start (loop, &sigint_cb); |
1054 | ev_signal_start (loop, &sigint_cb); |
959 | |
1055 | |
960 | |
1056 | |
961 | =head2 C<ev_idle> - when you've got nothing better to do |
1057 | =head2 C<ev_idle> - when you've got nothing better to do... |
962 | |
1058 | |
963 | Idle watchers trigger events when there are no other events are pending |
1059 | Idle watchers trigger events when there are no other events are pending |
964 | (prepare, check and other idle watchers do not count). That is, as long |
1060 | (prepare, check and other idle watchers do not count). That is, as long |
965 | as your process is busy handling sockets or timeouts (or even signals, |
1061 | as your process is busy handling sockets or timeouts (or even signals, |
966 | imagine) it will not be triggered. But when your process is idle all idle |
1062 | imagine) it will not be triggered. But when your process is idle all idle |
… | |
… | |
1000 | struct ev_idle *idle_watcher = malloc (sizeof (struct ev_idle)); |
1096 | struct ev_idle *idle_watcher = malloc (sizeof (struct ev_idle)); |
1001 | ev_idle_init (idle_watcher, idle_cb); |
1097 | ev_idle_init (idle_watcher, idle_cb); |
1002 | ev_idle_start (loop, idle_cb); |
1098 | ev_idle_start (loop, idle_cb); |
1003 | |
1099 | |
1004 | |
1100 | |
1005 | =head2 C<ev_prepare> and C<ev_check> - customise your event loop |
1101 | =head2 C<ev_prepare> and C<ev_check> - customise your event loop! |
1006 | |
1102 | |
1007 | Prepare and check watchers are usually (but not always) used in tandem: |
1103 | Prepare and check watchers are usually (but not always) used in tandem: |
1008 | prepare watchers get invoked before the process blocks and check watchers |
1104 | prepare watchers get invoked before the process blocks and check watchers |
1009 | afterwards. |
1105 | afterwards. |
1010 | |
1106 | |
|
|
1107 | You I<must not> call C<ev_loop> or similar functions that enter |
|
|
1108 | the current event loop from either C<ev_prepare> or C<ev_check> |
|
|
1109 | watchers. Other loops than the current one are fine, however. The |
|
|
1110 | rationale behind this is that you do not need to check for recursion in |
|
|
1111 | those watchers, i.e. the sequence will always be C<ev_prepare>, blocking, |
|
|
1112 | C<ev_check> so if you have one watcher of each kind they will always be |
|
|
1113 | called in pairs bracketing the blocking call. |
|
|
1114 | |
1011 | Their main purpose is to integrate other event mechanisms into libev. This |
1115 | Their main purpose is to integrate other event mechanisms into libev and |
1012 | could be used, for example, to track variable changes, implement your own |
1116 | their use is somewhat advanced. This could be used, for example, to track |
1013 | watchers, integrate net-snmp or a coroutine library and lots more. |
1117 | variable changes, implement your own watchers, integrate net-snmp or a |
|
|
1118 | coroutine library and lots more. They are also occasionally useful if |
|
|
1119 | you cache some data and want to flush it before blocking (for example, |
|
|
1120 | in X programs you might want to do an C<XFlush ()> in an C<ev_prepare> |
|
|
1121 | watcher). |
1014 | |
1122 | |
1015 | This is done by examining in each prepare call which file descriptors need |
1123 | This is done by examining in each prepare call which file descriptors need |
1016 | to be watched by the other library, registering C<ev_io> watchers for |
1124 | to be watched by the other library, registering C<ev_io> watchers for |
1017 | them and starting an C<ev_timer> watcher for any timeouts (many libraries |
1125 | them and starting an C<ev_timer> watcher for any timeouts (many libraries |
1018 | provide just this functionality). Then, in the check watcher you check for |
1126 | provide just this functionality). Then, in the check watcher you check for |
… | |
… | |
1040 | parameters of any kind. There are C<ev_prepare_set> and C<ev_check_set> |
1148 | parameters of any kind. There are C<ev_prepare_set> and C<ev_check_set> |
1041 | macros, but using them is utterly, utterly and completely pointless. |
1149 | macros, but using them is utterly, utterly and completely pointless. |
1042 | |
1150 | |
1043 | =back |
1151 | =back |
1044 | |
1152 | |
1045 | Example: *TODO*. |
1153 | Example: To include a library such as adns, you would add IO watchers |
|
|
1154 | and a timeout watcher in a prepare handler, as required by libadns, and |
|
|
1155 | in a check watcher, destroy them and call into libadns. What follows is |
|
|
1156 | pseudo-code only of course: |
|
|
1157 | |
|
|
1158 | static ev_io iow [nfd]; |
|
|
1159 | static ev_timer tw; |
|
|
1160 | |
|
|
1161 | static void |
|
|
1162 | io_cb (ev_loop *loop, ev_io *w, int revents) |
|
|
1163 | { |
|
|
1164 | // set the relevant poll flags |
|
|
1165 | // could also call adns_processreadable etc. here |
|
|
1166 | struct pollfd *fd = (struct pollfd *)w->data; |
|
|
1167 | if (revents & EV_READ ) fd->revents |= fd->events & POLLIN; |
|
|
1168 | if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT; |
|
|
1169 | } |
|
|
1170 | |
|
|
1171 | // create io watchers for each fd and a timer before blocking |
|
|
1172 | static void |
|
|
1173 | adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
|
|
1174 | { |
|
|
1175 | int timeout = 3600000;truct pollfd fds [nfd]; |
|
|
1176 | // actual code will need to loop here and realloc etc. |
|
|
1177 | adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ())); |
|
|
1178 | |
|
|
1179 | /* the callback is illegal, but won't be called as we stop during check */ |
|
|
1180 | ev_timer_init (&tw, 0, timeout * 1e-3); |
|
|
1181 | ev_timer_start (loop, &tw); |
|
|
1182 | |
|
|
1183 | // create on ev_io per pollfd |
|
|
1184 | for (int i = 0; i < nfd; ++i) |
|
|
1185 | { |
|
|
1186 | ev_io_init (iow + i, io_cb, fds [i].fd, |
|
|
1187 | ((fds [i].events & POLLIN ? EV_READ : 0) |
|
|
1188 | | (fds [i].events & POLLOUT ? EV_WRITE : 0))); |
|
|
1189 | |
|
|
1190 | fds [i].revents = 0; |
|
|
1191 | iow [i].data = fds + i; |
|
|
1192 | ev_io_start (loop, iow + i); |
|
|
1193 | } |
|
|
1194 | } |
|
|
1195 | |
|
|
1196 | // stop all watchers after blocking |
|
|
1197 | static void |
|
|
1198 | adns_check_cb (ev_loop *loop, ev_check *w, int revents) |
|
|
1199 | { |
|
|
1200 | ev_timer_stop (loop, &tw); |
|
|
1201 | |
|
|
1202 | for (int i = 0; i < nfd; ++i) |
|
|
1203 | ev_io_stop (loop, iow + i); |
|
|
1204 | |
|
|
1205 | adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop)); |
|
|
1206 | } |
|
|
1207 | |
|
|
1208 | |
|
|
1209 | =head2 C<ev_embed> - when one backend isn't enough... |
|
|
1210 | |
|
|
1211 | This is a rather advanced watcher type that lets you embed one event loop |
|
|
1212 | into another (currently only C<ev_io> events are supported in the embedded |
|
|
1213 | loop, other types of watchers might be handled in a delayed or incorrect |
|
|
1214 | fashion and must not be used). |
|
|
1215 | |
|
|
1216 | There are primarily two reasons you would want that: work around bugs and |
|
|
1217 | prioritise I/O. |
|
|
1218 | |
|
|
1219 | As an example for a bug workaround, the kqueue backend might only support |
|
|
1220 | sockets on some platform, so it is unusable as generic backend, but you |
|
|
1221 | still want to make use of it because you have many sockets and it scales |
|
|
1222 | so nicely. In this case, you would create a kqueue-based loop and embed it |
|
|
1223 | into your default loop (which might use e.g. poll). Overall operation will |
|
|
1224 | be a bit slower because first libev has to poll and then call kevent, but |
|
|
1225 | at least you can use both at what they are best. |
|
|
1226 | |
|
|
1227 | As for prioritising I/O: rarely you have the case where some fds have |
|
|
1228 | to be watched and handled very quickly (with low latency), and even |
|
|
1229 | priorities and idle watchers might have too much overhead. In this case |
|
|
1230 | you would put all the high priority stuff in one loop and all the rest in |
|
|
1231 | a second one, and embed the second one in the first. |
|
|
1232 | |
|
|
1233 | As long as the watcher is active, the callback will be invoked every time |
|
|
1234 | there might be events pending in the embedded loop. The callback must then |
|
|
1235 | call C<ev_embed_sweep (mainloop, watcher)> to make a single sweep and invoke |
|
|
1236 | their callbacks (you could also start an idle watcher to give the embedded |
|
|
1237 | loop strictly lower priority for example). You can also set the callback |
|
|
1238 | to C<0>, in which case the embed watcher will automatically execute the |
|
|
1239 | embedded loop sweep. |
|
|
1240 | |
|
|
1241 | As long as the watcher is started it will automatically handle events. The |
|
|
1242 | callback will be invoked whenever some events have been handled. You can |
|
|
1243 | set the callback to C<0> to avoid having to specify one if you are not |
|
|
1244 | interested in that. |
|
|
1245 | |
|
|
1246 | Also, there have not currently been made special provisions for forking: |
|
|
1247 | when you fork, you not only have to call C<ev_loop_fork> on both loops, |
|
|
1248 | but you will also have to stop and restart any C<ev_embed> watchers |
|
|
1249 | yourself. |
|
|
1250 | |
|
|
1251 | Unfortunately, not all backends are embeddable, only the ones returned by |
|
|
1252 | C<ev_embeddable_backends> are, which, unfortunately, does not include any |
|
|
1253 | portable one. |
|
|
1254 | |
|
|
1255 | So when you want to use this feature you will always have to be prepared |
|
|
1256 | that you cannot get an embeddable loop. The recommended way to get around |
|
|
1257 | this is to have a separate variables for your embeddable loop, try to |
|
|
1258 | create it, and if that fails, use the normal loop for everything: |
|
|
1259 | |
|
|
1260 | struct ev_loop *loop_hi = ev_default_init (0); |
|
|
1261 | struct ev_loop *loop_lo = 0; |
|
|
1262 | struct ev_embed embed; |
|
|
1263 | |
|
|
1264 | // see if there is a chance of getting one that works |
|
|
1265 | // (remember that a flags value of 0 means autodetection) |
|
|
1266 | loop_lo = ev_embeddable_backends () & ev_recommended_backends () |
|
|
1267 | ? ev_loop_new (ev_embeddable_backends () & ev_recommended_backends ()) |
|
|
1268 | : 0; |
|
|
1269 | |
|
|
1270 | // if we got one, then embed it, otherwise default to loop_hi |
|
|
1271 | if (loop_lo) |
|
|
1272 | { |
|
|
1273 | ev_embed_init (&embed, 0, loop_lo); |
|
|
1274 | ev_embed_start (loop_hi, &embed); |
|
|
1275 | } |
|
|
1276 | else |
|
|
1277 | loop_lo = loop_hi; |
|
|
1278 | |
|
|
1279 | =over 4 |
|
|
1280 | |
|
|
1281 | =item ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop) |
|
|
1282 | |
|
|
1283 | =item ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop) |
|
|
1284 | |
|
|
1285 | Configures the watcher to embed the given loop, which must be |
|
|
1286 | embeddable. If the callback is C<0>, then C<ev_embed_sweep> will be |
|
|
1287 | invoked automatically, otherwise it is the responsibility of the callback |
|
|
1288 | to invoke it (it will continue to be called until the sweep has been done, |
|
|
1289 | if you do not want thta, you need to temporarily stop the embed watcher). |
|
|
1290 | |
|
|
1291 | =item ev_embed_sweep (loop, ev_embed *) |
|
|
1292 | |
|
|
1293 | Make a single, non-blocking sweep over the embedded loop. This works |
|
|
1294 | similarly to C<ev_loop (embedded_loop, EVLOOP_NONBLOCK)>, but in the most |
|
|
1295 | apropriate way for embedded loops. |
|
|
1296 | |
|
|
1297 | =back |
1046 | |
1298 | |
1047 | |
1299 | |
1048 | =head1 OTHER FUNCTIONS |
1300 | =head1 OTHER FUNCTIONS |
1049 | |
1301 | |
1050 | There are some other functions of possible interest. Described. Here. Now. |
1302 | There are some other functions of possible interest. Described. Here. Now. |
… | |
… | |
1081 | /* stdin might have data for us, joy! */; |
1333 | /* stdin might have data for us, joy! */; |
1082 | } |
1334 | } |
1083 | |
1335 | |
1084 | ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0); |
1336 | ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0); |
1085 | |
1337 | |
1086 | =item ev_feed_event (loop, watcher, int events) |
1338 | =item ev_feed_event (ev_loop *, watcher *, int revents) |
1087 | |
1339 | |
1088 | Feeds the given event set into the event loop, as if the specified event |
1340 | Feeds the given event set into the event loop, as if the specified event |
1089 | had happened for the specified watcher (which must be a pointer to an |
1341 | had happened for the specified watcher (which must be a pointer to an |
1090 | initialised but not necessarily started event watcher). |
1342 | initialised but not necessarily started event watcher). |
1091 | |
1343 | |
1092 | =item ev_feed_fd_event (loop, int fd, int revents) |
1344 | =item ev_feed_fd_event (ev_loop *, int fd, int revents) |
1093 | |
1345 | |
1094 | Feed an event on the given fd, as if a file descriptor backend detected |
1346 | Feed an event on the given fd, as if a file descriptor backend detected |
1095 | the given events it. |
1347 | the given events it. |
1096 | |
1348 | |
1097 | =item ev_feed_signal_event (loop, int signum) |
1349 | =item ev_feed_signal_event (ev_loop *loop, int signum) |
1098 | |
1350 | |
1099 | Feed an event as if the given signal occured (loop must be the default loop!). |
1351 | Feed an event as if the given signal occured (C<loop> must be the default |
|
|
1352 | loop!). |
1100 | |
1353 | |
1101 | =back |
1354 | =back |
1102 | |
1355 | |
1103 | |
1356 | |
1104 | =head1 LIBEVENT EMULATION |
1357 | =head1 LIBEVENT EMULATION |
… | |
… | |
1128 | |
1381 | |
1129 | =back |
1382 | =back |
1130 | |
1383 | |
1131 | =head1 C++ SUPPORT |
1384 | =head1 C++ SUPPORT |
1132 | |
1385 | |
1133 | TBD. |
1386 | Libev comes with some simplistic wrapper classes for C++ that mainly allow |
|
|
1387 | you to use some convinience methods to start/stop watchers and also change |
|
|
1388 | the callback model to a model using method callbacks on objects. |
|
|
1389 | |
|
|
1390 | To use it, |
|
|
1391 | |
|
|
1392 | #include <ev++.h> |
|
|
1393 | |
|
|
1394 | (it is not installed by default). This automatically includes F<ev.h> |
|
|
1395 | and puts all of its definitions (many of them macros) into the global |
|
|
1396 | namespace. All C++ specific things are put into the C<ev> namespace. |
|
|
1397 | |
|
|
1398 | It should support all the same embedding options as F<ev.h>, most notably |
|
|
1399 | C<EV_MULTIPLICITY>. |
|
|
1400 | |
|
|
1401 | Here is a list of things available in the C<ev> namespace: |
|
|
1402 | |
|
|
1403 | =over 4 |
|
|
1404 | |
|
|
1405 | =item C<ev::READ>, C<ev::WRITE> etc. |
|
|
1406 | |
|
|
1407 | These are just enum values with the same values as the C<EV_READ> etc. |
|
|
1408 | macros from F<ev.h>. |
|
|
1409 | |
|
|
1410 | =item C<ev::tstamp>, C<ev::now> |
|
|
1411 | |
|
|
1412 | Aliases to the same types/functions as with the C<ev_> prefix. |
|
|
1413 | |
|
|
1414 | =item C<ev::io>, C<ev::timer>, C<ev::periodic>, C<ev::idle>, C<ev::sig> etc. |
|
|
1415 | |
|
|
1416 | For each C<ev_TYPE> watcher in F<ev.h> there is a corresponding class of |
|
|
1417 | the same name in the C<ev> namespace, with the exception of C<ev_signal> |
|
|
1418 | which is called C<ev::sig> to avoid clashes with the C<signal> macro |
|
|
1419 | defines by many implementations. |
|
|
1420 | |
|
|
1421 | All of those classes have these methods: |
|
|
1422 | |
|
|
1423 | =over 4 |
|
|
1424 | |
|
|
1425 | =item ev::TYPE::TYPE (object *, object::method *) |
|
|
1426 | |
|
|
1427 | =item ev::TYPE::TYPE (object *, object::method *, struct ev_loop *) |
|
|
1428 | |
|
|
1429 | =item ev::TYPE::~TYPE |
|
|
1430 | |
|
|
1431 | The constructor takes a pointer to an object and a method pointer to |
|
|
1432 | the event handler callback to call in this class. The constructor calls |
|
|
1433 | C<ev_init> for you, which means you have to call the C<set> method |
|
|
1434 | before starting it. If you do not specify a loop then the constructor |
|
|
1435 | automatically associates the default loop with this watcher. |
|
|
1436 | |
|
|
1437 | The destructor automatically stops the watcher if it is active. |
|
|
1438 | |
|
|
1439 | =item w->set (struct ev_loop *) |
|
|
1440 | |
|
|
1441 | Associates a different C<struct ev_loop> with this watcher. You can only |
|
|
1442 | do this when the watcher is inactive (and not pending either). |
|
|
1443 | |
|
|
1444 | =item w->set ([args]) |
|
|
1445 | |
|
|
1446 | Basically the same as C<ev_TYPE_set>, with the same args. Must be |
|
|
1447 | called at least once. Unlike the C counterpart, an active watcher gets |
|
|
1448 | automatically stopped and restarted. |
|
|
1449 | |
|
|
1450 | =item w->start () |
|
|
1451 | |
|
|
1452 | Starts the watcher. Note that there is no C<loop> argument as the |
|
|
1453 | constructor already takes the loop. |
|
|
1454 | |
|
|
1455 | =item w->stop () |
|
|
1456 | |
|
|
1457 | Stops the watcher if it is active. Again, no C<loop> argument. |
|
|
1458 | |
|
|
1459 | =item w->again () C<ev::timer>, C<ev::periodic> only |
|
|
1460 | |
|
|
1461 | For C<ev::timer> and C<ev::periodic>, this invokes the corresponding |
|
|
1462 | C<ev_TYPE_again> function. |
|
|
1463 | |
|
|
1464 | =item w->sweep () C<ev::embed> only |
|
|
1465 | |
|
|
1466 | Invokes C<ev_embed_sweep>. |
|
|
1467 | |
|
|
1468 | =back |
|
|
1469 | |
|
|
1470 | =back |
|
|
1471 | |
|
|
1472 | Example: Define a class with an IO and idle watcher, start one of them in |
|
|
1473 | the constructor. |
|
|
1474 | |
|
|
1475 | class myclass |
|
|
1476 | { |
|
|
1477 | ev_io io; void io_cb (ev::io &w, int revents); |
|
|
1478 | ev_idle idle void idle_cb (ev::idle &w, int revents); |
|
|
1479 | |
|
|
1480 | myclass (); |
|
|
1481 | } |
|
|
1482 | |
|
|
1483 | myclass::myclass (int fd) |
|
|
1484 | : io (this, &myclass::io_cb), |
|
|
1485 | idle (this, &myclass::idle_cb) |
|
|
1486 | { |
|
|
1487 | io.start (fd, ev::READ); |
|
|
1488 | } |
|
|
1489 | |
|
|
1490 | =head1 EMBEDDING |
|
|
1491 | |
|
|
1492 | Libev can (and often is) directly embedded into host |
|
|
1493 | applications. Examples of applications that embed it include the Deliantra |
|
|
1494 | Game Server, the EV perl module, the GNU Virtual Private Ethernet (gvpe) |
|
|
1495 | and rxvt-unicode. |
|
|
1496 | |
|
|
1497 | The goal is to enable you to just copy the neecssary files into your |
|
|
1498 | source directory without having to change even a single line in them, so |
|
|
1499 | you can easily upgrade by simply copying (or having a checked-out copy of |
|
|
1500 | libev somewhere in your source tree). |
|
|
1501 | |
|
|
1502 | =head2 FILESETS |
|
|
1503 | |
|
|
1504 | Depending on what features you need you need to include one or more sets of files |
|
|
1505 | in your app. |
|
|
1506 | |
|
|
1507 | =head3 CORE EVENT LOOP |
|
|
1508 | |
|
|
1509 | To include only the libev core (all the C<ev_*> functions), with manual |
|
|
1510 | configuration (no autoconf): |
|
|
1511 | |
|
|
1512 | #define EV_STANDALONE 1 |
|
|
1513 | #include "ev.c" |
|
|
1514 | |
|
|
1515 | This will automatically include F<ev.h>, too, and should be done in a |
|
|
1516 | single C source file only to provide the function implementations. To use |
|
|
1517 | it, do the same for F<ev.h> in all files wishing to use this API (best |
|
|
1518 | done by writing a wrapper around F<ev.h> that you can include instead and |
|
|
1519 | where you can put other configuration options): |
|
|
1520 | |
|
|
1521 | #define EV_STANDALONE 1 |
|
|
1522 | #include "ev.h" |
|
|
1523 | |
|
|
1524 | Both header files and implementation files can be compiled with a C++ |
|
|
1525 | compiler (at least, thats a stated goal, and breakage will be treated |
|
|
1526 | as a bug). |
|
|
1527 | |
|
|
1528 | You need the following files in your source tree, or in a directory |
|
|
1529 | in your include path (e.g. in libev/ when using -Ilibev): |
|
|
1530 | |
|
|
1531 | ev.h |
|
|
1532 | ev.c |
|
|
1533 | ev_vars.h |
|
|
1534 | ev_wrap.h |
|
|
1535 | |
|
|
1536 | ev_win32.c required on win32 platforms only |
|
|
1537 | |
|
|
1538 | ev_select.c only when select backend is enabled (which is by default) |
|
|
1539 | ev_poll.c only when poll backend is enabled (disabled by default) |
|
|
1540 | ev_epoll.c only when the epoll backend is enabled (disabled by default) |
|
|
1541 | ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
|
|
1542 | ev_port.c only when the solaris port backend is enabled (disabled by default) |
|
|
1543 | |
|
|
1544 | F<ev.c> includes the backend files directly when enabled, so you only need |
|
|
1545 | to compile this single file. |
|
|
1546 | |
|
|
1547 | =head3 LIBEVENT COMPATIBILITY API |
|
|
1548 | |
|
|
1549 | To include the libevent compatibility API, also include: |
|
|
1550 | |
|
|
1551 | #include "event.c" |
|
|
1552 | |
|
|
1553 | in the file including F<ev.c>, and: |
|
|
1554 | |
|
|
1555 | #include "event.h" |
|
|
1556 | |
|
|
1557 | in the files that want to use the libevent API. This also includes F<ev.h>. |
|
|
1558 | |
|
|
1559 | You need the following additional files for this: |
|
|
1560 | |
|
|
1561 | event.h |
|
|
1562 | event.c |
|
|
1563 | |
|
|
1564 | =head3 AUTOCONF SUPPORT |
|
|
1565 | |
|
|
1566 | Instead of using C<EV_STANDALONE=1> and providing your config in |
|
|
1567 | whatever way you want, you can also C<m4_include([libev.m4])> in your |
|
|
1568 | F<configure.ac> and leave C<EV_STANDALONE> undefined. F<ev.c> will then |
|
|
1569 | include F<config.h> and configure itself accordingly. |
|
|
1570 | |
|
|
1571 | For this of course you need the m4 file: |
|
|
1572 | |
|
|
1573 | libev.m4 |
|
|
1574 | |
|
|
1575 | =head2 PREPROCESSOR SYMBOLS/MACROS |
|
|
1576 | |
|
|
1577 | Libev can be configured via a variety of preprocessor symbols you have to define |
|
|
1578 | before including any of its files. The default is not to build for multiplicity |
|
|
1579 | and only include the select backend. |
|
|
1580 | |
|
|
1581 | =over 4 |
|
|
1582 | |
|
|
1583 | =item EV_STANDALONE |
|
|
1584 | |
|
|
1585 | Must always be C<1> if you do not use autoconf configuration, which |
|
|
1586 | keeps libev from including F<config.h>, and it also defines dummy |
|
|
1587 | implementations for some libevent functions (such as logging, which is not |
|
|
1588 | supported). It will also not define any of the structs usually found in |
|
|
1589 | F<event.h> that are not directly supported by the libev core alone. |
|
|
1590 | |
|
|
1591 | =item EV_USE_MONOTONIC |
|
|
1592 | |
|
|
1593 | If defined to be C<1>, libev will try to detect the availability of the |
|
|
1594 | monotonic clock option at both compiletime and runtime. Otherwise no use |
|
|
1595 | of the monotonic clock option will be attempted. If you enable this, you |
|
|
1596 | usually have to link against librt or something similar. Enabling it when |
|
|
1597 | the functionality isn't available is safe, though, althoguh you have |
|
|
1598 | to make sure you link against any libraries where the C<clock_gettime> |
|
|
1599 | function is hiding in (often F<-lrt>). |
|
|
1600 | |
|
|
1601 | =item EV_USE_REALTIME |
|
|
1602 | |
|
|
1603 | If defined to be C<1>, libev will try to detect the availability of the |
|
|
1604 | realtime clock option at compiletime (and assume its availability at |
|
|
1605 | runtime if successful). Otherwise no use of the realtime clock option will |
|
|
1606 | be attempted. This effectively replaces C<gettimeofday> by C<clock_get |
|
|
1607 | (CLOCK_REALTIME, ...)> and will not normally affect correctness. See tzhe note about libraries |
|
|
1608 | in the description of C<EV_USE_MONOTONIC>, though. |
|
|
1609 | |
|
|
1610 | =item EV_USE_SELECT |
|
|
1611 | |
|
|
1612 | If undefined or defined to be C<1>, libev will compile in support for the |
|
|
1613 | C<select>(2) backend. No attempt at autodetection will be done: if no |
|
|
1614 | other method takes over, select will be it. Otherwise the select backend |
|
|
1615 | will not be compiled in. |
|
|
1616 | |
|
|
1617 | =item EV_SELECT_USE_FD_SET |
|
|
1618 | |
|
|
1619 | If defined to C<1>, then the select backend will use the system C<fd_set> |
|
|
1620 | structure. This is useful if libev doesn't compile due to a missing |
|
|
1621 | C<NFDBITS> or C<fd_mask> definition or it misguesses the bitset layout on |
|
|
1622 | exotic systems. This usually limits the range of file descriptors to some |
|
|
1623 | low limit such as 1024 or might have other limitations (winsocket only |
|
|
1624 | allows 64 sockets). The C<FD_SETSIZE> macro, set before compilation, might |
|
|
1625 | influence the size of the C<fd_set> used. |
|
|
1626 | |
|
|
1627 | =item EV_SELECT_IS_WINSOCKET |
|
|
1628 | |
|
|
1629 | When defined to C<1>, the select backend will assume that |
|
|
1630 | select/socket/connect etc. don't understand file descriptors but |
|
|
1631 | wants osf handles on win32 (this is the case when the select to |
|
|
1632 | be used is the winsock select). This means that it will call |
|
|
1633 | C<_get_osfhandle> on the fd to convert it to an OS handle. Otherwise, |
|
|
1634 | it is assumed that all these functions actually work on fds, even |
|
|
1635 | on win32. Should not be defined on non-win32 platforms. |
|
|
1636 | |
|
|
1637 | =item EV_USE_POLL |
|
|
1638 | |
|
|
1639 | If defined to be C<1>, libev will compile in support for the C<poll>(2) |
|
|
1640 | backend. Otherwise it will be enabled on non-win32 platforms. It |
|
|
1641 | takes precedence over select. |
|
|
1642 | |
|
|
1643 | =item EV_USE_EPOLL |
|
|
1644 | |
|
|
1645 | If defined to be C<1>, libev will compile in support for the Linux |
|
|
1646 | C<epoll>(7) backend. Its availability will be detected at runtime, |
|
|
1647 | otherwise another method will be used as fallback. This is the |
|
|
1648 | preferred backend for GNU/Linux systems. |
|
|
1649 | |
|
|
1650 | =item EV_USE_KQUEUE |
|
|
1651 | |
|
|
1652 | If defined to be C<1>, libev will compile in support for the BSD style |
|
|
1653 | C<kqueue>(2) backend. Its actual availability will be detected at runtime, |
|
|
1654 | otherwise another method will be used as fallback. This is the preferred |
|
|
1655 | backend for BSD and BSD-like systems, although on most BSDs kqueue only |
|
|
1656 | supports some types of fds correctly (the only platform we found that |
|
|
1657 | supports ptys for example was NetBSD), so kqueue might be compiled in, but |
|
|
1658 | not be used unless explicitly requested. The best way to use it is to find |
|
|
1659 | out whether kqueue supports your type of fd properly and use an embedded |
|
|
1660 | kqueue loop. |
|
|
1661 | |
|
|
1662 | =item EV_USE_PORT |
|
|
1663 | |
|
|
1664 | If defined to be C<1>, libev will compile in support for the Solaris |
|
|
1665 | 10 port style backend. Its availability will be detected at runtime, |
|
|
1666 | otherwise another method will be used as fallback. This is the preferred |
|
|
1667 | backend for Solaris 10 systems. |
|
|
1668 | |
|
|
1669 | =item EV_USE_DEVPOLL |
|
|
1670 | |
|
|
1671 | reserved for future expansion, works like the USE symbols above. |
|
|
1672 | |
|
|
1673 | =item EV_H |
|
|
1674 | |
|
|
1675 | The name of the F<ev.h> header file used to include it. The default if |
|
|
1676 | undefined is C<< <ev.h> >> in F<event.h> and C<"ev.h"> in F<ev.c>. This |
|
|
1677 | can be used to virtually rename the F<ev.h> header file in case of conflicts. |
|
|
1678 | |
|
|
1679 | =item EV_CONFIG_H |
|
|
1680 | |
|
|
1681 | If C<EV_STANDALONE> isn't C<1>, this variable can be used to override |
|
|
1682 | F<ev.c>'s idea of where to find the F<config.h> file, similarly to |
|
|
1683 | C<EV_H>, above. |
|
|
1684 | |
|
|
1685 | =item EV_EVENT_H |
|
|
1686 | |
|
|
1687 | Similarly to C<EV_H>, this macro can be used to override F<event.c>'s idea |
|
|
1688 | of how the F<event.h> header can be found. |
|
|
1689 | |
|
|
1690 | =item EV_PROTOTYPES |
|
|
1691 | |
|
|
1692 | If defined to be C<0>, then F<ev.h> will not define any function |
|
|
1693 | prototypes, but still define all the structs and other symbols. This is |
|
|
1694 | occasionally useful if you want to provide your own wrapper functions |
|
|
1695 | around libev functions. |
|
|
1696 | |
|
|
1697 | =item EV_MULTIPLICITY |
|
|
1698 | |
|
|
1699 | If undefined or defined to C<1>, then all event-loop-specific functions |
|
|
1700 | will have the C<struct ev_loop *> as first argument, and you can create |
|
|
1701 | additional independent event loops. Otherwise there will be no support |
|
|
1702 | for multiple event loops and there is no first event loop pointer |
|
|
1703 | argument. Instead, all functions act on the single default loop. |
|
|
1704 | |
|
|
1705 | =item EV_PERIODICS |
|
|
1706 | |
|
|
1707 | If undefined or defined to be C<1>, then periodic timers are supported, |
|
|
1708 | otherwise not. This saves a few kb of code. |
|
|
1709 | |
|
|
1710 | =item EV_COMMON |
|
|
1711 | |
|
|
1712 | By default, all watchers have a C<void *data> member. By redefining |
|
|
1713 | this macro to a something else you can include more and other types of |
|
|
1714 | members. You have to define it each time you include one of the files, |
|
|
1715 | though, and it must be identical each time. |
|
|
1716 | |
|
|
1717 | For example, the perl EV module uses something like this: |
|
|
1718 | |
|
|
1719 | #define EV_COMMON \ |
|
|
1720 | SV *self; /* contains this struct */ \ |
|
|
1721 | SV *cb_sv, *fh /* note no trailing ";" */ |
|
|
1722 | |
|
|
1723 | =item EV_CB_DECLARE (type) |
|
|
1724 | |
|
|
1725 | =item EV_CB_INVOKE (watcher, revents) |
|
|
1726 | |
|
|
1727 | =item ev_set_cb (ev, cb) |
|
|
1728 | |
|
|
1729 | Can be used to change the callback member declaration in each watcher, |
|
|
1730 | and the way callbacks are invoked and set. Must expand to a struct member |
|
|
1731 | definition and a statement, respectively. See the F<ev.v> header file for |
|
|
1732 | their default definitions. One possible use for overriding these is to |
|
|
1733 | avoid the C<struct ev_loop *> as first argument in all cases, or to use |
|
|
1734 | method calls instead of plain function calls in C++. |
|
|
1735 | |
|
|
1736 | =head2 EXAMPLES |
|
|
1737 | |
|
|
1738 | For a real-world example of a program the includes libev |
|
|
1739 | verbatim, you can have a look at the EV perl module |
|
|
1740 | (L<http://software.schmorp.de/pkg/EV.html>). It has the libev files in |
|
|
1741 | the F<libev/> subdirectory and includes them in the F<EV/EVAPI.h> (public |
|
|
1742 | interface) and F<EV.xs> (implementation) files. Only the F<EV.xs> file |
|
|
1743 | will be compiled. It is pretty complex because it provides its own header |
|
|
1744 | file. |
|
|
1745 | |
|
|
1746 | The usage in rxvt-unicode is simpler. It has a F<ev_cpp.h> header file |
|
|
1747 | that everybody includes and which overrides some autoconf choices: |
|
|
1748 | |
|
|
1749 | #define EV_USE_POLL 0 |
|
|
1750 | #define EV_MULTIPLICITY 0 |
|
|
1751 | #define EV_PERIODICS 0 |
|
|
1752 | #define EV_CONFIG_H <config.h> |
|
|
1753 | |
|
|
1754 | #include "ev++.h" |
|
|
1755 | |
|
|
1756 | And a F<ev_cpp.C> implementation file that contains libev proper and is compiled: |
|
|
1757 | |
|
|
1758 | #include "ev_cpp.h" |
|
|
1759 | #include "ev.c" |
|
|
1760 | |
|
|
1761 | |
|
|
1762 | =head1 COMPLEXITIES |
|
|
1763 | |
|
|
1764 | In this section the complexities of (many of) the algorithms used inside |
|
|
1765 | libev will be explained. For complexity discussions about backends see the |
|
|
1766 | documentation for C<ev_default_init>. |
|
|
1767 | |
|
|
1768 | =over 4 |
|
|
1769 | |
|
|
1770 | =item Starting and stopping timer/periodic watchers: O(log skipped_other_timers) |
|
|
1771 | |
|
|
1772 | =item Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers) |
|
|
1773 | |
|
|
1774 | =item Starting io/check/prepare/idle/signal/child watchers: O(1) |
|
|
1775 | |
|
|
1776 | =item Stopping check/prepare/idle watchers: O(1) |
|
|
1777 | |
|
|
1778 | =item Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % 16)) |
|
|
1779 | |
|
|
1780 | =item Finding the next timer per loop iteration: O(1) |
|
|
1781 | |
|
|
1782 | =item Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd) |
|
|
1783 | |
|
|
1784 | =item Activating one watcher: O(1) |
|
|
1785 | |
|
|
1786 | =back |
|
|
1787 | |
1134 | |
1788 | |
1135 | =head1 AUTHOR |
1789 | =head1 AUTHOR |
1136 | |
1790 | |
1137 | Marc Lehmann <libev@schmorp.de>. |
1791 | Marc Lehmann <libev@schmorp.de>. |
1138 | |
1792 | |