… | |
… | |
26 | puts ("stdin ready"); |
26 | puts ("stdin ready"); |
27 | // for one-shot events, one must manually stop the watcher |
27 | // for one-shot events, one must manually stop the watcher |
28 | // with its corresponding stop function. |
28 | // with its corresponding stop function. |
29 | ev_io_stop (EV_A_ w); |
29 | ev_io_stop (EV_A_ w); |
30 | |
30 | |
31 | // this causes all nested ev_loop's to stop iterating |
31 | // this causes all nested ev_run's to stop iterating |
32 | ev_unloop (EV_A_ EVUNLOOP_ALL); |
32 | ev_break (EV_A_ EVBREAK_ALL); |
33 | } |
33 | } |
34 | |
34 | |
35 | // another callback, this time for a time-out |
35 | // another callback, this time for a time-out |
36 | static void |
36 | static void |
37 | timeout_cb (EV_P_ ev_timer *w, int revents) |
37 | timeout_cb (EV_P_ ev_timer *w, int revents) |
38 | { |
38 | { |
39 | puts ("timeout"); |
39 | puts ("timeout"); |
40 | // this causes the innermost ev_loop to stop iterating |
40 | // this causes the innermost ev_run to stop iterating |
41 | ev_unloop (EV_A_ EVUNLOOP_ONE); |
41 | ev_break (EV_A_ EVBREAK_ONE); |
42 | } |
42 | } |
43 | |
43 | |
44 | int |
44 | int |
45 | main (void) |
45 | main (void) |
46 | { |
46 | { |
… | |
… | |
56 | // simple non-repeating 5.5 second timeout |
56 | // simple non-repeating 5.5 second timeout |
57 | ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.); |
57 | ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.); |
58 | ev_timer_start (loop, &timeout_watcher); |
58 | ev_timer_start (loop, &timeout_watcher); |
59 | |
59 | |
60 | // now wait for events to arrive |
60 | // now wait for events to arrive |
61 | ev_loop (loop, 0); |
61 | ev_run (loop, 0); |
62 | |
62 | |
63 | // unloop was called, so exit |
63 | // unloop was called, so exit |
64 | return 0; |
64 | return 0; |
65 | } |
65 | } |
66 | |
66 | |
… | |
… | |
292 | |
292 | |
293 | =back |
293 | =back |
294 | |
294 | |
295 | =head1 FUNCTIONS CONTROLLING THE EVENT LOOP |
295 | =head1 FUNCTIONS CONTROLLING THE EVENT LOOP |
296 | |
296 | |
297 | An event loop is described by a C<struct ev_loop *> (the C<struct> |
297 | An event loop is described by a C<struct ev_loop *> (the C<struct> is |
298 | is I<not> optional in this case, as there is also an C<ev_loop> |
298 | I<not> optional in this case unless libev 3 compatibility is disabled, as |
299 | I<function>). |
299 | libev 3 had an C<ev_loop> function colliding with the struct name). |
300 | |
300 | |
301 | The library knows two types of such loops, the I<default> loop, which |
301 | The library knows two types of such loops, the I<default> loop, which |
302 | supports signals and child events, and dynamically created loops which do |
302 | supports signals and child events, and dynamically created event loops |
303 | not. |
303 | which do not. |
304 | |
304 | |
305 | =over 4 |
305 | =over 4 |
306 | |
306 | |
307 | =item struct ev_loop *ev_default_loop (unsigned int flags) |
307 | =item struct ev_loop *ev_default_loop (unsigned int flags) |
308 | |
308 | |
… | |
… | |
606 | Like C<ev_default_destroy>, but destroys an event loop created by an |
606 | Like C<ev_default_destroy>, but destroys an event loop created by an |
607 | earlier call to C<ev_loop_new>. |
607 | earlier call to C<ev_loop_new>. |
608 | |
608 | |
609 | =item ev_default_fork () |
609 | =item ev_default_fork () |
610 | |
610 | |
611 | This function sets a flag that causes subsequent C<ev_loop> iterations |
611 | This function sets a flag that causes subsequent C<ev_run> iterations |
612 | to reinitialise the kernel state for backends that have one. Despite the |
612 | to reinitialise the kernel state for backends that have one. Despite the |
613 | name, you can call it anytime, but it makes most sense after forking, in |
613 | name, you can call it anytime, but it makes most sense after forking, in |
614 | the child process (or both child and parent, but that again makes little |
614 | the child process (or both child and parent, but that again makes little |
615 | sense). You I<must> call it in the child before using any of the libev |
615 | sense). You I<must> call it in the child before using any of the libev |
616 | functions, and it will only take effect at the next C<ev_loop> iteration. |
616 | functions, and it will only take effect at the next C<ev_run> iteration. |
617 | |
617 | |
618 | Again, you I<have> to call it on I<any> loop that you want to re-use after |
618 | Again, you I<have> to call it on I<any> loop that you want to re-use after |
619 | a fork, I<even if you do not plan to use the loop in the parent>. This is |
619 | a fork, I<even if you do not plan to use the loop in the parent>. This is |
620 | because some kernel interfaces *cough* I<kqueue> *cough* do funny things |
620 | because some kernel interfaces *cough* I<kqueue> *cough* do funny things |
621 | during fork. |
621 | during fork. |
622 | |
622 | |
623 | On the other hand, you only need to call this function in the child |
623 | On the other hand, you only need to call this function in the child |
624 | process if and only if you want to use the event loop in the child. If you |
624 | process if and only if you want to use the event loop in the child. If |
625 | just fork+exec or create a new loop in the child, you don't have to call |
625 | you just fork+exec or create a new loop in the child, you don't have to |
626 | it at all. |
626 | call it at all (in fact, C<epoll> is so badly broken that it makes a |
|
|
627 | difference, but libev will usually detect this case on its own and do a |
|
|
628 | costly reset of the backend). |
627 | |
629 | |
628 | The function itself is quite fast and it's usually not a problem to call |
630 | The function itself is quite fast and it's usually not a problem to call |
629 | it just in case after a fork. To make this easy, the function will fit in |
631 | it just in case after a fork. To make this easy, the function will fit in |
630 | quite nicely into a call to C<pthread_atfork>: |
632 | quite nicely into a call to C<pthread_atfork>: |
631 | |
633 | |
… | |
… | |
643 | Returns true when the given loop is, in fact, the default loop, and false |
645 | Returns true when the given loop is, in fact, the default loop, and false |
644 | otherwise. |
646 | otherwise. |
645 | |
647 | |
646 | =item unsigned int ev_iteration (loop) |
648 | =item unsigned int ev_iteration (loop) |
647 | |
649 | |
648 | Returns the current iteration count for the loop, which is identical to |
650 | Returns the current iteration count for the event loop, which is identical |
649 | the number of times libev did poll for new events. It starts at C<0> and |
651 | to the number of times libev did poll for new events. It starts at C<0> |
650 | happily wraps around with enough iterations. |
652 | and happily wraps around with enough iterations. |
651 | |
653 | |
652 | This value can sometimes be useful as a generation counter of sorts (it |
654 | This value can sometimes be useful as a generation counter of sorts (it |
653 | "ticks" the number of loop iterations), as it roughly corresponds with |
655 | "ticks" the number of loop iterations), as it roughly corresponds with |
654 | C<ev_prepare> and C<ev_check> calls - and is incremented between the |
656 | C<ev_prepare> and C<ev_check> calls - and is incremented between the |
655 | prepare and check phases. |
657 | prepare and check phases. |
656 | |
658 | |
657 | =item unsigned int ev_depth (loop) |
659 | =item unsigned int ev_depth (loop) |
658 | |
660 | |
659 | Returns the number of times C<ev_loop> was entered minus the number of |
661 | Returns the number of times C<ev_run> was entered minus the number of |
660 | times C<ev_loop> was exited, in other words, the recursion depth. |
662 | times C<ev_run> was exited, in other words, the recursion depth. |
661 | |
663 | |
662 | Outside C<ev_loop>, this number is zero. In a callback, this number is |
664 | Outside C<ev_run>, this number is zero. In a callback, this number is |
663 | C<1>, unless C<ev_loop> was invoked recursively (or from another thread), |
665 | C<1>, unless C<ev_run> was invoked recursively (or from another thread), |
664 | in which case it is higher. |
666 | in which case it is higher. |
665 | |
667 | |
666 | Leaving C<ev_loop> abnormally (setjmp/longjmp, cancelling the thread |
668 | Leaving C<ev_run> abnormally (setjmp/longjmp, cancelling the thread |
667 | etc.), doesn't count as "exit" - consider this as a hint to avoid such |
669 | etc.), doesn't count as "exit" - consider this as a hint to avoid such |
668 | ungentleman behaviour unless it's really convenient. |
670 | ungentleman-like behaviour unless it's really convenient. |
669 | |
671 | |
670 | =item unsigned int ev_backend (loop) |
672 | =item unsigned int ev_backend (loop) |
671 | |
673 | |
672 | Returns one of the C<EVBACKEND_*> flags indicating the event backend in |
674 | Returns one of the C<EVBACKEND_*> flags indicating the event backend in |
673 | use. |
675 | use. |
… | |
… | |
682 | |
684 | |
683 | =item ev_now_update (loop) |
685 | =item ev_now_update (loop) |
684 | |
686 | |
685 | Establishes the current time by querying the kernel, updating the time |
687 | Establishes the current time by querying the kernel, updating the time |
686 | returned by C<ev_now ()> in the progress. This is a costly operation and |
688 | returned by C<ev_now ()> in the progress. This is a costly operation and |
687 | is usually done automatically within C<ev_loop ()>. |
689 | is usually done automatically within C<ev_run ()>. |
688 | |
690 | |
689 | This function is rarely useful, but when some event callback runs for a |
691 | This function is rarely useful, but when some event callback runs for a |
690 | very long time without entering the event loop, updating libev's idea of |
692 | very long time without entering the event loop, updating libev's idea of |
691 | the current time is a good idea. |
693 | the current time is a good idea. |
692 | |
694 | |
… | |
… | |
694 | |
696 | |
695 | =item ev_suspend (loop) |
697 | =item ev_suspend (loop) |
696 | |
698 | |
697 | =item ev_resume (loop) |
699 | =item ev_resume (loop) |
698 | |
700 | |
699 | These two functions suspend and resume a loop, for use when the loop is |
701 | These two functions suspend and resume an event loop, for use when the |
700 | not used for a while and timeouts should not be processed. |
702 | loop is not used for a while and timeouts should not be processed. |
701 | |
703 | |
702 | A typical use case would be an interactive program such as a game: When |
704 | A typical use case would be an interactive program such as a game: When |
703 | the user presses C<^Z> to suspend the game and resumes it an hour later it |
705 | the user presses C<^Z> to suspend the game and resumes it an hour later it |
704 | would be best to handle timeouts as if no time had actually passed while |
706 | would be best to handle timeouts as if no time had actually passed while |
705 | the program was suspended. This can be achieved by calling C<ev_suspend> |
707 | the program was suspended. This can be achieved by calling C<ev_suspend> |
… | |
… | |
716 | without a previous call to C<ev_suspend>. |
718 | without a previous call to C<ev_suspend>. |
717 | |
719 | |
718 | Calling C<ev_suspend>/C<ev_resume> has the side effect of updating the |
720 | Calling C<ev_suspend>/C<ev_resume> has the side effect of updating the |
719 | event loop time (see C<ev_now_update>). |
721 | event loop time (see C<ev_now_update>). |
720 | |
722 | |
721 | =item ev_loop (loop, int flags) |
723 | =item ev_run (loop, int flags) |
722 | |
724 | |
723 | Finally, this is it, the event handler. This function usually is called |
725 | Finally, this is it, the event handler. This function usually is called |
724 | after you have initialised all your watchers and you want to start |
726 | after you have initialised all your watchers and you want to start |
725 | handling events. |
727 | handling events. It will ask the operating system for any new events, call |
|
|
728 | the watcher callbacks, an then repeat the whole process indefinitely: This |
|
|
729 | is why event loops are called I<loops>. |
726 | |
730 | |
727 | If the flags argument is specified as C<0>, it will not return until |
731 | If the flags argument is specified as C<0>, it will keep handling events |
728 | either no event watchers are active anymore or C<ev_unloop> was called. |
732 | until either no event watchers are active anymore or C<ev_break> was |
|
|
733 | called. |
729 | |
734 | |
730 | Please note that an explicit C<ev_unloop> is usually better than |
735 | Please note that an explicit C<ev_break> is usually better than |
731 | relying on all watchers to be stopped when deciding when a program has |
736 | relying on all watchers to be stopped when deciding when a program has |
732 | finished (especially in interactive programs), but having a program |
737 | finished (especially in interactive programs), but having a program |
733 | that automatically loops as long as it has to and no longer by virtue |
738 | that automatically loops as long as it has to and no longer by virtue |
734 | of relying on its watchers stopping correctly, that is truly a thing of |
739 | of relying on its watchers stopping correctly, that is truly a thing of |
735 | beauty. |
740 | beauty. |
736 | |
741 | |
737 | A flags value of C<EVLOOP_NONBLOCK> will look for new events, will handle |
742 | A flags value of C<EVRUN_NOWAIT> will look for new events, will handle |
738 | those events and any already outstanding ones, but will not block your |
743 | those events and any already outstanding ones, but will not wait and |
739 | process in case there are no events and will return after one iteration of |
744 | block your process in case there are no events and will return after one |
740 | the loop. |
745 | iteration of the loop. This is sometimes useful to poll and handle new |
|
|
746 | events while doing lengthy calculations, to keep the program responsive. |
741 | |
747 | |
742 | A flags value of C<EVLOOP_ONESHOT> will look for new events (waiting if |
748 | A flags value of C<EVRUN_ONCE> will look for new events (waiting if |
743 | necessary) and will handle those and any already outstanding ones. It |
749 | necessary) and will handle those and any already outstanding ones. It |
744 | will block your process until at least one new event arrives (which could |
750 | will block your process until at least one new event arrives (which could |
745 | be an event internal to libev itself, so there is no guarantee that a |
751 | be an event internal to libev itself, so there is no guarantee that a |
746 | user-registered callback will be called), and will return after one |
752 | user-registered callback will be called), and will return after one |
747 | iteration of the loop. |
753 | iteration of the loop. |
748 | |
754 | |
749 | This is useful if you are waiting for some external event in conjunction |
755 | This is useful if you are waiting for some external event in conjunction |
750 | with something not expressible using other libev watchers (i.e. "roll your |
756 | with something not expressible using other libev watchers (i.e. "roll your |
751 | own C<ev_loop>"). However, a pair of C<ev_prepare>/C<ev_check> watchers is |
757 | own C<ev_run>"). However, a pair of C<ev_prepare>/C<ev_check> watchers is |
752 | usually a better approach for this kind of thing. |
758 | usually a better approach for this kind of thing. |
753 | |
759 | |
754 | Here are the gory details of what C<ev_loop> does: |
760 | Here are the gory details of what C<ev_run> does: |
755 | |
761 | |
|
|
762 | - Increment loop depth. |
|
|
763 | - Reset the ev_break status. |
756 | - Before the first iteration, call any pending watchers. |
764 | - Before the first iteration, call any pending watchers. |
|
|
765 | LOOP: |
757 | * If EVFLAG_FORKCHECK was used, check for a fork. |
766 | - If EVFLAG_FORKCHECK was used, check for a fork. |
758 | - If a fork was detected (by any means), queue and call all fork watchers. |
767 | - If a fork was detected (by any means), queue and call all fork watchers. |
759 | - Queue and call all prepare watchers. |
768 | - Queue and call all prepare watchers. |
|
|
769 | - If ev_break was called, goto FINISH. |
760 | - If we have been forked, detach and recreate the kernel state |
770 | - If we have been forked, detach and recreate the kernel state |
761 | as to not disturb the other process. |
771 | as to not disturb the other process. |
762 | - Update the kernel state with all outstanding changes. |
772 | - Update the kernel state with all outstanding changes. |
763 | - Update the "event loop time" (ev_now ()). |
773 | - Update the "event loop time" (ev_now ()). |
764 | - Calculate for how long to sleep or block, if at all |
774 | - Calculate for how long to sleep or block, if at all |
765 | (active idle watchers, EVLOOP_NONBLOCK or not having |
775 | (active idle watchers, EVRUN_NOWAIT or not having |
766 | any active watchers at all will result in not sleeping). |
776 | any active watchers at all will result in not sleeping). |
767 | - Sleep if the I/O and timer collect interval say so. |
777 | - Sleep if the I/O and timer collect interval say so. |
|
|
778 | - Increment loop iteration counter. |
768 | - Block the process, waiting for any events. |
779 | - Block the process, waiting for any events. |
769 | - Queue all outstanding I/O (fd) events. |
780 | - Queue all outstanding I/O (fd) events. |
770 | - Update the "event loop time" (ev_now ()), and do time jump adjustments. |
781 | - Update the "event loop time" (ev_now ()), and do time jump adjustments. |
771 | - Queue all expired timers. |
782 | - Queue all expired timers. |
772 | - Queue all expired periodics. |
783 | - Queue all expired periodics. |
773 | - Unless any events are pending now, queue all idle watchers. |
784 | - Queue all idle watchers with priority higher than that of pending events. |
774 | - Queue all check watchers. |
785 | - Queue all check watchers. |
775 | - Call all queued watchers in reverse order (i.e. check watchers first). |
786 | - Call all queued watchers in reverse order (i.e. check watchers first). |
776 | Signals and child watchers are implemented as I/O watchers, and will |
787 | Signals and child watchers are implemented as I/O watchers, and will |
777 | be handled here by queueing them when their watcher gets executed. |
788 | be handled here by queueing them when their watcher gets executed. |
778 | - If ev_unloop has been called, or EVLOOP_ONESHOT or EVLOOP_NONBLOCK |
789 | - If ev_break has been called, or EVRUN_ONCE or EVRUN_NOWAIT |
779 | were used, or there are no active watchers, return, otherwise |
790 | were used, or there are no active watchers, goto FINISH, otherwise |
780 | continue with step *. |
791 | continue with step LOOP. |
|
|
792 | FINISH: |
|
|
793 | - Reset the ev_break status iff it was EVBREAK_ONE. |
|
|
794 | - Decrement the loop depth. |
|
|
795 | - Return. |
781 | |
796 | |
782 | Example: Queue some jobs and then loop until no events are outstanding |
797 | Example: Queue some jobs and then loop until no events are outstanding |
783 | anymore. |
798 | anymore. |
784 | |
799 | |
785 | ... queue jobs here, make sure they register event watchers as long |
800 | ... queue jobs here, make sure they register event watchers as long |
786 | ... as they still have work to do (even an idle watcher will do..) |
801 | ... as they still have work to do (even an idle watcher will do..) |
787 | ev_loop (my_loop, 0); |
802 | ev_run (my_loop, 0); |
788 | ... jobs done or somebody called unloop. yeah! |
803 | ... jobs done or somebody called unloop. yeah! |
789 | |
804 | |
790 | =item ev_unloop (loop, how) |
805 | =item ev_break (loop, how) |
791 | |
806 | |
792 | Can be used to make a call to C<ev_loop> return early (but only after it |
807 | Can be used to make a call to C<ev_run> return early (but only after it |
793 | has processed all outstanding events). The C<how> argument must be either |
808 | has processed all outstanding events). The C<how> argument must be either |
794 | C<EVUNLOOP_ONE>, which will make the innermost C<ev_loop> call return, or |
809 | C<EVBREAK_ONE>, which will make the innermost C<ev_run> call return, or |
795 | C<EVUNLOOP_ALL>, which will make all nested C<ev_loop> calls return. |
810 | C<EVBREAK_ALL>, which will make all nested C<ev_run> calls return. |
796 | |
811 | |
797 | This "unloop state" will be cleared when entering C<ev_loop> again. |
812 | This "unloop state" will be cleared when entering C<ev_run> again. |
798 | |
813 | |
799 | It is safe to call C<ev_unloop> from outside any C<ev_loop> calls. |
814 | It is safe to call C<ev_break> from outside any C<ev_run> calls. ##TODO## |
800 | |
815 | |
801 | =item ev_ref (loop) |
816 | =item ev_ref (loop) |
802 | |
817 | |
803 | =item ev_unref (loop) |
818 | =item ev_unref (loop) |
804 | |
819 | |
805 | Ref/unref can be used to add or remove a reference count on the event |
820 | Ref/unref can be used to add or remove a reference count on the event |
806 | loop: Every watcher keeps one reference, and as long as the reference |
821 | loop: Every watcher keeps one reference, and as long as the reference |
807 | count is nonzero, C<ev_loop> will not return on its own. |
822 | count is nonzero, C<ev_run> will not return on its own. |
808 | |
823 | |
809 | This is useful when you have a watcher that you never intend to |
824 | This is useful when you have a watcher that you never intend to |
810 | unregister, but that nevertheless should not keep C<ev_loop> from |
825 | unregister, but that nevertheless should not keep C<ev_run> from |
811 | returning. In such a case, call C<ev_unref> after starting, and C<ev_ref> |
826 | returning. In such a case, call C<ev_unref> after starting, and C<ev_ref> |
812 | before stopping it. |
827 | before stopping it. |
813 | |
828 | |
814 | As an example, libev itself uses this for its internal signal pipe: It |
829 | As an example, libev itself uses this for its internal signal pipe: It |
815 | is not visible to the libev user and should not keep C<ev_loop> from |
830 | is not visible to the libev user and should not keep C<ev_run> from |
816 | exiting if no event watchers registered by it are active. It is also an |
831 | exiting if no event watchers registered by it are active. It is also an |
817 | excellent way to do this for generic recurring timers or from within |
832 | excellent way to do this for generic recurring timers or from within |
818 | third-party libraries. Just remember to I<unref after start> and I<ref |
833 | third-party libraries. Just remember to I<unref after start> and I<ref |
819 | before stop> (but only if the watcher wasn't active before, or was active |
834 | before stop> (but only if the watcher wasn't active before, or was active |
820 | before, respectively. Note also that libev might stop watchers itself |
835 | before, respectively. Note also that libev might stop watchers itself |
821 | (e.g. non-repeating timers) in which case you have to C<ev_ref> |
836 | (e.g. non-repeating timers) in which case you have to C<ev_ref> |
822 | in the callback). |
837 | in the callback). |
823 | |
838 | |
824 | Example: Create a signal watcher, but keep it from keeping C<ev_loop> |
839 | Example: Create a signal watcher, but keep it from keeping C<ev_run> |
825 | running when nothing else is active. |
840 | running when nothing else is active. |
826 | |
841 | |
827 | ev_signal exitsig; |
842 | ev_signal exitsig; |
828 | ev_signal_init (&exitsig, sig_cb, SIGINT); |
843 | ev_signal_init (&exitsig, sig_cb, SIGINT); |
829 | ev_signal_start (loop, &exitsig); |
844 | ev_signal_start (loop, &exitsig); |
… | |
… | |
892 | ev_set_io_collect_interval (EV_DEFAULT_UC_ 0.01); |
907 | ev_set_io_collect_interval (EV_DEFAULT_UC_ 0.01); |
893 | |
908 | |
894 | =item ev_invoke_pending (loop) |
909 | =item ev_invoke_pending (loop) |
895 | |
910 | |
896 | This call will simply invoke all pending watchers while resetting their |
911 | This call will simply invoke all pending watchers while resetting their |
897 | pending state. Normally, C<ev_loop> does this automatically when required, |
912 | pending state. Normally, C<ev_run> does this automatically when required, |
898 | but when overriding the invoke callback this call comes handy. |
913 | but when overriding the invoke callback this call comes handy. |
899 | |
914 | |
900 | =item int ev_pending_count (loop) |
915 | =item int ev_pending_count (loop) |
901 | |
916 | |
902 | Returns the number of pending watchers - zero indicates that no watchers |
917 | Returns the number of pending watchers - zero indicates that no watchers |
903 | are pending. |
918 | are pending. |
904 | |
919 | |
905 | =item ev_set_invoke_pending_cb (loop, void (*invoke_pending_cb)(EV_P)) |
920 | =item ev_set_invoke_pending_cb (loop, void (*invoke_pending_cb)(EV_P)) |
906 | |
921 | |
907 | This overrides the invoke pending functionality of the loop: Instead of |
922 | This overrides the invoke pending functionality of the loop: Instead of |
908 | invoking all pending watchers when there are any, C<ev_loop> will call |
923 | invoking all pending watchers when there are any, C<ev_run> will call |
909 | this callback instead. This is useful, for example, when you want to |
924 | this callback instead. This is useful, for example, when you want to |
910 | invoke the actual watchers inside another context (another thread etc.). |
925 | invoke the actual watchers inside another context (another thread etc.). |
911 | |
926 | |
912 | If you want to reset the callback, use C<ev_invoke_pending> as new |
927 | If you want to reset the callback, use C<ev_invoke_pending> as new |
913 | callback. |
928 | callback. |
… | |
… | |
916 | |
931 | |
917 | Sometimes you want to share the same loop between multiple threads. This |
932 | Sometimes you want to share the same loop between multiple threads. This |
918 | can be done relatively simply by putting mutex_lock/unlock calls around |
933 | can be done relatively simply by putting mutex_lock/unlock calls around |
919 | each call to a libev function. |
934 | each call to a libev function. |
920 | |
935 | |
921 | However, C<ev_loop> can run an indefinite time, so it is not feasible to |
936 | However, C<ev_run> can run an indefinite time, so it is not feasible |
922 | wait for it to return. One way around this is to wake up the loop via |
937 | to wait for it to return. One way around this is to wake up the event |
923 | C<ev_unloop> and C<av_async_send>, another way is to set these I<release> |
938 | loop via C<ev_break> and C<av_async_send>, another way is to set these |
924 | and I<acquire> callbacks on the loop. |
939 | I<release> and I<acquire> callbacks on the loop. |
925 | |
940 | |
926 | When set, then C<release> will be called just before the thread is |
941 | When set, then C<release> will be called just before the thread is |
927 | suspended waiting for new events, and C<acquire> is called just |
942 | suspended waiting for new events, and C<acquire> is called just |
928 | afterwards. |
943 | afterwards. |
929 | |
944 | |
… | |
… | |
932 | |
947 | |
933 | While event loop modifications are allowed between invocations of |
948 | While event loop modifications are allowed between invocations of |
934 | C<release> and C<acquire> (that's their only purpose after all), no |
949 | C<release> and C<acquire> (that's their only purpose after all), no |
935 | modifications done will affect the event loop, i.e. adding watchers will |
950 | modifications done will affect the event loop, i.e. adding watchers will |
936 | have no effect on the set of file descriptors being watched, or the time |
951 | have no effect on the set of file descriptors being watched, or the time |
937 | waited. Use an C<ev_async> watcher to wake up C<ev_loop> when you want it |
952 | waited. Use an C<ev_async> watcher to wake up C<ev_run> when you want it |
938 | to take note of any changes you made. |
953 | to take note of any changes you made. |
939 | |
954 | |
940 | In theory, threads executing C<ev_loop> will be async-cancel safe between |
955 | In theory, threads executing C<ev_run> will be async-cancel safe between |
941 | invocations of C<release> and C<acquire>. |
956 | invocations of C<release> and C<acquire>. |
942 | |
957 | |
943 | See also the locking example in the C<THREADS> section later in this |
958 | See also the locking example in the C<THREADS> section later in this |
944 | document. |
959 | document. |
945 | |
960 | |
… | |
… | |
954 | These two functions can be used to associate arbitrary data with a loop, |
969 | These two functions can be used to associate arbitrary data with a loop, |
955 | and are intended solely for the C<invoke_pending_cb>, C<release> and |
970 | and are intended solely for the C<invoke_pending_cb>, C<release> and |
956 | C<acquire> callbacks described above, but of course can be (ab-)used for |
971 | C<acquire> callbacks described above, but of course can be (ab-)used for |
957 | any other purpose as well. |
972 | any other purpose as well. |
958 | |
973 | |
959 | =item ev_loop_verify (loop) |
974 | =item ev_verify (loop) |
960 | |
975 | |
961 | This function only does something when C<EV_VERIFY> support has been |
976 | This function only does something when C<EV_VERIFY> support has been |
962 | compiled in, which is the default for non-minimal builds. It tries to go |
977 | compiled in, which is the default for non-minimal builds. It tries to go |
963 | through all internal structures and checks them for validity. If anything |
978 | through all internal structures and checks them for validity. If anything |
964 | is found to be inconsistent, it will print an error message to standard |
979 | is found to be inconsistent, it will print an error message to standard |
… | |
… | |
975 | |
990 | |
976 | In the following description, uppercase C<TYPE> in names stands for the |
991 | In the following description, uppercase C<TYPE> in names stands for the |
977 | watcher type, e.g. C<ev_TYPE_start> can mean C<ev_timer_start> for timer |
992 | watcher type, e.g. C<ev_TYPE_start> can mean C<ev_timer_start> for timer |
978 | watchers and C<ev_io_start> for I/O watchers. |
993 | watchers and C<ev_io_start> for I/O watchers. |
979 | |
994 | |
980 | A watcher is a structure that you create and register to record your |
995 | A watcher is an opaque structure that you allocate and register to record |
981 | interest in some event. For instance, if you want to wait for STDIN to |
996 | your interest in some event. To make a concrete example, imagine you want |
982 | become readable, you would create an C<ev_io> watcher for that: |
997 | to wait for STDIN to become readable, you would create an C<ev_io> watcher |
|
|
998 | for that: |
983 | |
999 | |
984 | static void my_cb (struct ev_loop *loop, ev_io *w, int revents) |
1000 | static void my_cb (struct ev_loop *loop, ev_io *w, int revents) |
985 | { |
1001 | { |
986 | ev_io_stop (w); |
1002 | ev_io_stop (w); |
987 | ev_unloop (loop, EVUNLOOP_ALL); |
1003 | ev_break (loop, EVBREAK_ALL); |
988 | } |
1004 | } |
989 | |
1005 | |
990 | struct ev_loop *loop = ev_default_loop (0); |
1006 | struct ev_loop *loop = ev_default_loop (0); |
991 | |
1007 | |
992 | ev_io stdin_watcher; |
1008 | ev_io stdin_watcher; |
993 | |
1009 | |
994 | ev_init (&stdin_watcher, my_cb); |
1010 | ev_init (&stdin_watcher, my_cb); |
995 | ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ); |
1011 | ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ); |
996 | ev_io_start (loop, &stdin_watcher); |
1012 | ev_io_start (loop, &stdin_watcher); |
997 | |
1013 | |
998 | ev_loop (loop, 0); |
1014 | ev_run (loop, 0); |
999 | |
1015 | |
1000 | As you can see, you are responsible for allocating the memory for your |
1016 | As you can see, you are responsible for allocating the memory for your |
1001 | watcher structures (and it is I<usually> a bad idea to do this on the |
1017 | watcher structures (and it is I<usually> a bad idea to do this on the |
1002 | stack). |
1018 | stack). |
1003 | |
1019 | |
1004 | Each watcher has an associated watcher structure (called C<struct ev_TYPE> |
1020 | Each watcher has an associated watcher structure (called C<struct ev_TYPE> |
1005 | or simply C<ev_TYPE>, as typedefs are provided for all watcher structs). |
1021 | or simply C<ev_TYPE>, as typedefs are provided for all watcher structs). |
1006 | |
1022 | |
1007 | Each watcher structure must be initialised by a call to C<ev_init |
1023 | Each watcher structure must be initialised by a call to C<ev_init (watcher |
1008 | (watcher *, callback)>, which expects a callback to be provided. This |
1024 | *, callback)>, which expects a callback to be provided. This callback is |
1009 | callback gets invoked each time the event occurs (or, in the case of I/O |
1025 | invoked each time the event occurs (or, in the case of I/O watchers, each |
1010 | watchers, each time the event loop detects that the file descriptor given |
1026 | time the event loop detects that the file descriptor given is readable |
1011 | is readable and/or writable). |
1027 | and/or writable). |
1012 | |
1028 | |
1013 | Each watcher type further has its own C<< ev_TYPE_set (watcher *, ...) >> |
1029 | Each watcher type further has its own C<< ev_TYPE_set (watcher *, ...) >> |
1014 | macro to configure it, with arguments specific to the watcher type. There |
1030 | macro to configure it, with arguments specific to the watcher type. There |
1015 | is also a macro to combine initialisation and setting in one call: C<< |
1031 | is also a macro to combine initialisation and setting in one call: C<< |
1016 | ev_TYPE_init (watcher *, callback, ...) >>. |
1032 | ev_TYPE_init (watcher *, callback, ...) >>. |
… | |
… | |
1067 | |
1083 | |
1068 | =item C<EV_PREPARE> |
1084 | =item C<EV_PREPARE> |
1069 | |
1085 | |
1070 | =item C<EV_CHECK> |
1086 | =item C<EV_CHECK> |
1071 | |
1087 | |
1072 | All C<ev_prepare> watchers are invoked just I<before> C<ev_loop> starts |
1088 | All C<ev_prepare> watchers are invoked just I<before> C<ev_run> starts |
1073 | to gather new events, and all C<ev_check> watchers are invoked just after |
1089 | to gather new events, and all C<ev_check> watchers are invoked just after |
1074 | C<ev_loop> has gathered them, but before it invokes any callbacks for any |
1090 | C<ev_run> has gathered them, but before it invokes any callbacks for any |
1075 | received events. Callbacks of both watcher types can start and stop as |
1091 | received events. Callbacks of both watcher types can start and stop as |
1076 | many watchers as they want, and all of them will be taken into account |
1092 | many watchers as they want, and all of them will be taken into account |
1077 | (for example, a C<ev_prepare> watcher might start an idle watcher to keep |
1093 | (for example, a C<ev_prepare> watcher might start an idle watcher to keep |
1078 | C<ev_loop> from blocking). |
1094 | C<ev_run> from blocking). |
1079 | |
1095 | |
1080 | =item C<EV_EMBED> |
1096 | =item C<EV_EMBED> |
1081 | |
1097 | |
1082 | The embedded event loop specified in the C<ev_embed> watcher needs attention. |
1098 | The embedded event loop specified in the C<ev_embed> watcher needs attention. |
1083 | |
1099 | |
… | |
… | |
1111 | example it might indicate that a fd is readable or writable, and if your |
1127 | example it might indicate that a fd is readable or writable, and if your |
1112 | callbacks is well-written it can just attempt the operation and cope with |
1128 | callbacks is well-written it can just attempt the operation and cope with |
1113 | the error from read() or write(). This will not work in multi-threaded |
1129 | the error from read() or write(). This will not work in multi-threaded |
1114 | programs, though, as the fd could already be closed and reused for another |
1130 | programs, though, as the fd could already be closed and reused for another |
1115 | thing, so beware. |
1131 | thing, so beware. |
|
|
1132 | |
|
|
1133 | =back |
|
|
1134 | |
|
|
1135 | =head2 WATCHER STATES |
|
|
1136 | |
|
|
1137 | There are various watcher states mentioned throughout this manual - |
|
|
1138 | active, pending and so on. In this section these states and the rules to |
|
|
1139 | transition between them will be described in more detail - and while these |
|
|
1140 | rules might look complicated, they usually do "the right thing". |
|
|
1141 | |
|
|
1142 | =over 4 |
|
|
1143 | |
|
|
1144 | =item initialiased |
|
|
1145 | |
|
|
1146 | Before a watcher can be registered with the event looop it has to be |
|
|
1147 | initialised. This can be done with a call to C<ev_TYPE_init>, or calls to |
|
|
1148 | C<ev_init> followed by the watcher-specific C<ev_TYPE_set> function. |
|
|
1149 | |
|
|
1150 | In this state it is simply some block of memory that is suitable for use |
|
|
1151 | in an event loop. It can be moved around, freed, reused etc. at will. |
|
|
1152 | |
|
|
1153 | =item started/running/active |
|
|
1154 | |
|
|
1155 | Once a watcher has been started with a call to C<ev_TYPE_start> it becomes |
|
|
1156 | property of the event loop, and is actively waiting for events. While in |
|
|
1157 | this state it cannot be accessed (except in a few documented ways), moved, |
|
|
1158 | freed or anything else - the only legal thing is to keep a pointer to it, |
|
|
1159 | and call libev functions on it that are documented to work on active watchers. |
|
|
1160 | |
|
|
1161 | =item pending |
|
|
1162 | |
|
|
1163 | If a watcher is active and libev determines that an event it is interested |
|
|
1164 | in has occured (such as a timer expiring), it will become pending. It will |
|
|
1165 | stay in this pending state until either it is stopped or its callback is |
|
|
1166 | about to be invoked, so it is not normally pending inside the watcher |
|
|
1167 | callback. |
|
|
1168 | |
|
|
1169 | The watcher might or might not be active while it is pending (for example, |
|
|
1170 | an expired non-repeating timer can be pending but no longer active). If it |
|
|
1171 | is stopped, it can be freely accessed (e.g. by calling C<ev_TYPE_set>), |
|
|
1172 | but it is still property of the event loop at this time, so cannot be |
|
|
1173 | moved, freed or reused. And if it is active the rules described in the |
|
|
1174 | previous item still apply. |
|
|
1175 | |
|
|
1176 | It is also possible to feed an event on a watcher that is not active (e.g. |
|
|
1177 | via C<ev_feed_event>), in which case it becomes pending without being |
|
|
1178 | active. |
|
|
1179 | |
|
|
1180 | =item stopped |
|
|
1181 | |
|
|
1182 | A watcher can be stopped implicitly by libev (in which case it might still |
|
|
1183 | be pending), or explicitly by calling its C<ev_TYPE_stop> function. The |
|
|
1184 | latter will clear any pending state the watcher might be in, regardless |
|
|
1185 | of whether it was active or not, so stopping a watcher explicitly before |
|
|
1186 | freeing it is often a good idea. |
|
|
1187 | |
|
|
1188 | While stopped (and not pending) the watcher is essentially in the |
|
|
1189 | initialised state, that is it can be reused, moved, modified in any way |
|
|
1190 | you wish. |
1116 | |
1191 | |
1117 | =back |
1192 | =back |
1118 | |
1193 | |
1119 | =head2 GENERIC WATCHER FUNCTIONS |
1194 | =head2 GENERIC WATCHER FUNCTIONS |
1120 | |
1195 | |
… | |
… | |
1624 | ... |
1699 | ... |
1625 | struct ev_loop *loop = ev_default_init (0); |
1700 | struct ev_loop *loop = ev_default_init (0); |
1626 | ev_io stdin_readable; |
1701 | ev_io stdin_readable; |
1627 | ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ); |
1702 | ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ); |
1628 | ev_io_start (loop, &stdin_readable); |
1703 | ev_io_start (loop, &stdin_readable); |
1629 | ev_loop (loop, 0); |
1704 | ev_run (loop, 0); |
1630 | |
1705 | |
1631 | |
1706 | |
1632 | =head2 C<ev_timer> - relative and optionally repeating timeouts |
1707 | =head2 C<ev_timer> - relative and optionally repeating timeouts |
1633 | |
1708 | |
1634 | Timer watchers are simple relative timers that generate an event after a |
1709 | Timer watchers are simple relative timers that generate an event after a |
… | |
… | |
1643 | The callback is guaranteed to be invoked only I<after> its timeout has |
1718 | The callback is guaranteed to be invoked only I<after> its timeout has |
1644 | passed (not I<at>, so on systems with very low-resolution clocks this |
1719 | passed (not I<at>, so on systems with very low-resolution clocks this |
1645 | might introduce a small delay). If multiple timers become ready during the |
1720 | might introduce a small delay). If multiple timers become ready during the |
1646 | same loop iteration then the ones with earlier time-out values are invoked |
1721 | same loop iteration then the ones with earlier time-out values are invoked |
1647 | before ones of the same priority with later time-out values (but this is |
1722 | before ones of the same priority with later time-out values (but this is |
1648 | no longer true when a callback calls C<ev_loop> recursively). |
1723 | no longer true when a callback calls C<ev_run> recursively). |
1649 | |
1724 | |
1650 | =head3 Be smart about timeouts |
1725 | =head3 Be smart about timeouts |
1651 | |
1726 | |
1652 | Many real-world problems involve some kind of timeout, usually for error |
1727 | Many real-world problems involve some kind of timeout, usually for error |
1653 | recovery. A typical example is an HTTP request - if the other side hangs, |
1728 | recovery. A typical example is an HTTP request - if the other side hangs, |
… | |
… | |
1824 | |
1899 | |
1825 | =head3 The special problem of time updates |
1900 | =head3 The special problem of time updates |
1826 | |
1901 | |
1827 | Establishing the current time is a costly operation (it usually takes at |
1902 | Establishing the current time is a costly operation (it usually takes at |
1828 | least two system calls): EV therefore updates its idea of the current |
1903 | least two system calls): EV therefore updates its idea of the current |
1829 | time only before and after C<ev_loop> collects new events, which causes a |
1904 | time only before and after C<ev_run> collects new events, which causes a |
1830 | growing difference between C<ev_now ()> and C<ev_time ()> when handling |
1905 | growing difference between C<ev_now ()> and C<ev_time ()> when handling |
1831 | lots of events in one iteration. |
1906 | lots of events in one iteration. |
1832 | |
1907 | |
1833 | The relative timeouts are calculated relative to the C<ev_now ()> |
1908 | The relative timeouts are calculated relative to the C<ev_now ()> |
1834 | time. This is usually the right thing as this timestamp refers to the time |
1909 | time. This is usually the right thing as this timestamp refers to the time |
… | |
… | |
1951 | } |
2026 | } |
1952 | |
2027 | |
1953 | ev_timer mytimer; |
2028 | ev_timer mytimer; |
1954 | ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */ |
2029 | ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */ |
1955 | ev_timer_again (&mytimer); /* start timer */ |
2030 | ev_timer_again (&mytimer); /* start timer */ |
1956 | ev_loop (loop, 0); |
2031 | ev_run (loop, 0); |
1957 | |
2032 | |
1958 | // and in some piece of code that gets executed on any "activity": |
2033 | // and in some piece of code that gets executed on any "activity": |
1959 | // reset the timeout to start ticking again at 10 seconds |
2034 | // reset the timeout to start ticking again at 10 seconds |
1960 | ev_timer_again (&mytimer); |
2035 | ev_timer_again (&mytimer); |
1961 | |
2036 | |
… | |
… | |
1987 | |
2062 | |
1988 | As with timers, the callback is guaranteed to be invoked only when the |
2063 | As with timers, the callback is guaranteed to be invoked only when the |
1989 | point in time where it is supposed to trigger has passed. If multiple |
2064 | point in time where it is supposed to trigger has passed. If multiple |
1990 | timers become ready during the same loop iteration then the ones with |
2065 | timers become ready during the same loop iteration then the ones with |
1991 | earlier time-out values are invoked before ones with later time-out values |
2066 | earlier time-out values are invoked before ones with later time-out values |
1992 | (but this is no longer true when a callback calls C<ev_loop> recursively). |
2067 | (but this is no longer true when a callback calls C<ev_run> recursively). |
1993 | |
2068 | |
1994 | =head3 Watcher-Specific Functions and Data Members |
2069 | =head3 Watcher-Specific Functions and Data Members |
1995 | |
2070 | |
1996 | =over 4 |
2071 | =over 4 |
1997 | |
2072 | |
… | |
… | |
2235 | Example: Try to exit cleanly on SIGINT. |
2310 | Example: Try to exit cleanly on SIGINT. |
2236 | |
2311 | |
2237 | static void |
2312 | static void |
2238 | sigint_cb (struct ev_loop *loop, ev_signal *w, int revents) |
2313 | sigint_cb (struct ev_loop *loop, ev_signal *w, int revents) |
2239 | { |
2314 | { |
2240 | ev_unloop (loop, EVUNLOOP_ALL); |
2315 | ev_break (loop, EVBREAK_ALL); |
2241 | } |
2316 | } |
2242 | |
2317 | |
2243 | ev_signal signal_watcher; |
2318 | ev_signal signal_watcher; |
2244 | ev_signal_init (&signal_watcher, sigint_cb, SIGINT); |
2319 | ev_signal_init (&signal_watcher, sigint_cb, SIGINT); |
2245 | ev_signal_start (loop, &signal_watcher); |
2320 | ev_signal_start (loop, &signal_watcher); |
… | |
… | |
2631 | |
2706 | |
2632 | Prepare and check watchers are usually (but not always) used in pairs: |
2707 | Prepare and check watchers are usually (but not always) used in pairs: |
2633 | prepare watchers get invoked before the process blocks and check watchers |
2708 | prepare watchers get invoked before the process blocks and check watchers |
2634 | afterwards. |
2709 | afterwards. |
2635 | |
2710 | |
2636 | You I<must not> call C<ev_loop> or similar functions that enter |
2711 | You I<must not> call C<ev_run> or similar functions that enter |
2637 | the current event loop from either C<ev_prepare> or C<ev_check> |
2712 | the current event loop from either C<ev_prepare> or C<ev_check> |
2638 | watchers. Other loops than the current one are fine, however. The |
2713 | watchers. Other loops than the current one are fine, however. The |
2639 | rationale behind this is that you do not need to check for recursion in |
2714 | rationale behind this is that you do not need to check for recursion in |
2640 | those watchers, i.e. the sequence will always be C<ev_prepare>, blocking, |
2715 | those watchers, i.e. the sequence will always be C<ev_prepare>, blocking, |
2641 | C<ev_check> so if you have one watcher of each kind they will always be |
2716 | C<ev_check> so if you have one watcher of each kind they will always be |
… | |
… | |
2809 | |
2884 | |
2810 | if (timeout >= 0) |
2885 | if (timeout >= 0) |
2811 | // create/start timer |
2886 | // create/start timer |
2812 | |
2887 | |
2813 | // poll |
2888 | // poll |
2814 | ev_loop (EV_A_ 0); |
2889 | ev_run (EV_A_ 0); |
2815 | |
2890 | |
2816 | // stop timer again |
2891 | // stop timer again |
2817 | if (timeout >= 0) |
2892 | if (timeout >= 0) |
2818 | ev_timer_stop (EV_A_ &to); |
2893 | ev_timer_stop (EV_A_ &to); |
2819 | |
2894 | |
… | |
… | |
2897 | if you do not want that, you need to temporarily stop the embed watcher). |
2972 | if you do not want that, you need to temporarily stop the embed watcher). |
2898 | |
2973 | |
2899 | =item ev_embed_sweep (loop, ev_embed *) |
2974 | =item ev_embed_sweep (loop, ev_embed *) |
2900 | |
2975 | |
2901 | Make a single, non-blocking sweep over the embedded loop. This works |
2976 | Make a single, non-blocking sweep over the embedded loop. This works |
2902 | similarly to C<ev_loop (embedded_loop, EVLOOP_NONBLOCK)>, but in the most |
2977 | similarly to C<ev_run (embedded_loop, EVRUN_NOWAIT)>, but in the most |
2903 | appropriate way for embedded loops. |
2978 | appropriate way for embedded loops. |
2904 | |
2979 | |
2905 | =item struct ev_loop *other [read-only] |
2980 | =item struct ev_loop *other [read-only] |
2906 | |
2981 | |
2907 | The embedded event loop. |
2982 | The embedded event loop. |
… | |
… | |
3013 | =back |
3088 | =back |
3014 | |
3089 | |
3015 | |
3090 | |
3016 | =head2 C<ev_async> - how to wake up an event loop |
3091 | =head2 C<ev_async> - how to wake up an event loop |
3017 | |
3092 | |
3018 | In general, you cannot use an C<ev_loop> from multiple threads or other |
3093 | In general, you cannot use an C<ev_run> from multiple threads or other |
3019 | asynchronous sources such as signal handlers (as opposed to multiple event |
3094 | asynchronous sources such as signal handlers (as opposed to multiple event |
3020 | loops - those are of course safe to use in different threads). |
3095 | loops - those are of course safe to use in different threads). |
3021 | |
3096 | |
3022 | Sometimes, however, you need to wake up an event loop you do not control, |
3097 | Sometimes, however, you need to wake up an event loop you do not control, |
3023 | for example because it belongs to another thread. This is what C<ev_async> |
3098 | for example because it belongs to another thread. This is what C<ev_async> |
… | |
… | |
3391 | Associates a different C<struct ev_loop> with this watcher. You can only |
3466 | Associates a different C<struct ev_loop> with this watcher. You can only |
3392 | do this when the watcher is inactive (and not pending either). |
3467 | do this when the watcher is inactive (and not pending either). |
3393 | |
3468 | |
3394 | =item w->set ([arguments]) |
3469 | =item w->set ([arguments]) |
3395 | |
3470 | |
3396 | Basically the same as C<ev_TYPE_set>, with the same arguments. Must be |
3471 | Basically the same as C<ev_TYPE_set>, with the same arguments. Either this |
3397 | called at least once. Unlike the C counterpart, an active watcher gets |
3472 | method or a suitable start method must be called at least once. Unlike the |
3398 | automatically stopped and restarted when reconfiguring it with this |
3473 | C counterpart, an active watcher gets automatically stopped and restarted |
3399 | method. |
3474 | when reconfiguring it with this method. |
3400 | |
3475 | |
3401 | =item w->start () |
3476 | =item w->start () |
3402 | |
3477 | |
3403 | Starts the watcher. Note that there is no C<loop> argument, as the |
3478 | Starts the watcher. Note that there is no C<loop> argument, as the |
3404 | constructor already stores the event loop. |
3479 | constructor already stores the event loop. |
3405 | |
3480 | |
|
|
3481 | =item w->start ([arguments]) |
|
|
3482 | |
|
|
3483 | Instead of calling C<set> and C<start> methods separately, it is often |
|
|
3484 | convenient to wrap them in one call. Uses the same type of arguments as |
|
|
3485 | the configure C<set> method of the watcher. |
|
|
3486 | |
3406 | =item w->stop () |
3487 | =item w->stop () |
3407 | |
3488 | |
3408 | Stops the watcher if it is active. Again, no C<loop> argument. |
3489 | Stops the watcher if it is active. Again, no C<loop> argument. |
3409 | |
3490 | |
3410 | =item w->again () (C<ev::timer>, C<ev::periodic> only) |
3491 | =item w->again () (C<ev::timer>, C<ev::periodic> only) |
… | |
… | |
3422 | |
3503 | |
3423 | =back |
3504 | =back |
3424 | |
3505 | |
3425 | =back |
3506 | =back |
3426 | |
3507 | |
3427 | Example: Define a class with an IO and idle watcher, start one of them in |
3508 | Example: Define a class with two I/O and idle watchers, start the I/O |
3428 | the constructor. |
3509 | watchers in the constructor. |
3429 | |
3510 | |
3430 | class myclass |
3511 | class myclass |
3431 | { |
3512 | { |
3432 | ev::io io ; void io_cb (ev::io &w, int revents); |
3513 | ev::io io ; void io_cb (ev::io &w, int revents); |
|
|
3514 | ev::io2 io2 ; void io2_cb (ev::io &w, int revents); |
3433 | ev::idle idle; void idle_cb (ev::idle &w, int revents); |
3515 | ev::idle idle; void idle_cb (ev::idle &w, int revents); |
3434 | |
3516 | |
3435 | myclass (int fd) |
3517 | myclass (int fd) |
3436 | { |
3518 | { |
3437 | io .set <myclass, &myclass::io_cb > (this); |
3519 | io .set <myclass, &myclass::io_cb > (this); |
|
|
3520 | io2 .set <myclass, &myclass::io2_cb > (this); |
3438 | idle.set <myclass, &myclass::idle_cb> (this); |
3521 | idle.set <myclass, &myclass::idle_cb> (this); |
3439 | |
3522 | |
3440 | io.start (fd, ev::READ); |
3523 | io.set (fd, ev::WRITE); // configure the watcher |
|
|
3524 | io.start (); // start it whenever convenient |
|
|
3525 | |
|
|
3526 | io2.start (fd, ev::READ); // set + start in one call |
3441 | } |
3527 | } |
3442 | }; |
3528 | }; |
3443 | |
3529 | |
3444 | |
3530 | |
3445 | =head1 OTHER LANGUAGE BINDINGS |
3531 | =head1 OTHER LANGUAGE BINDINGS |
… | |
… | |
3519 | loop argument"). The C<EV_A> form is used when this is the sole argument, |
3605 | loop argument"). The C<EV_A> form is used when this is the sole argument, |
3520 | C<EV_A_> is used when other arguments are following. Example: |
3606 | C<EV_A_> is used when other arguments are following. Example: |
3521 | |
3607 | |
3522 | ev_unref (EV_A); |
3608 | ev_unref (EV_A); |
3523 | ev_timer_add (EV_A_ watcher); |
3609 | ev_timer_add (EV_A_ watcher); |
3524 | ev_loop (EV_A_ 0); |
3610 | ev_run (EV_A_ 0); |
3525 | |
3611 | |
3526 | It assumes the variable C<loop> of type C<struct ev_loop *> is in scope, |
3612 | It assumes the variable C<loop> of type C<struct ev_loop *> is in scope, |
3527 | which is often provided by the following macro. |
3613 | which is often provided by the following macro. |
3528 | |
3614 | |
3529 | =item C<EV_P>, C<EV_P_> |
3615 | =item C<EV_P>, C<EV_P_> |
… | |
… | |
3569 | } |
3655 | } |
3570 | |
3656 | |
3571 | ev_check check; |
3657 | ev_check check; |
3572 | ev_check_init (&check, check_cb); |
3658 | ev_check_init (&check, check_cb); |
3573 | ev_check_start (EV_DEFAULT_ &check); |
3659 | ev_check_start (EV_DEFAULT_ &check); |
3574 | ev_loop (EV_DEFAULT_ 0); |
3660 | ev_run (EV_DEFAULT_ 0); |
3575 | |
3661 | |
3576 | =head1 EMBEDDING |
3662 | =head1 EMBEDDING |
3577 | |
3663 | |
3578 | Libev can (and often is) directly embedded into host |
3664 | Libev can (and often is) directly embedded into host |
3579 | applications. Examples of applications that embed it include the Deliantra |
3665 | applications. Examples of applications that embed it include the Deliantra |
… | |
… | |
3670 | to a compiled library. All other symbols change the ABI, which means all |
3756 | to a compiled library. All other symbols change the ABI, which means all |
3671 | users of libev and the libev code itself must be compiled with compatible |
3757 | users of libev and the libev code itself must be compiled with compatible |
3672 | settings. |
3758 | settings. |
3673 | |
3759 | |
3674 | =over 4 |
3760 | =over 4 |
|
|
3761 | |
|
|
3762 | =item EV_COMPAT3 (h) |
|
|
3763 | |
|
|
3764 | Backwards compatibility is a major concern for libev. This is why this |
|
|
3765 | release of libev comes with wrappers for the functions and symbols that |
|
|
3766 | have been renamed between libev version 3 and 4. |
|
|
3767 | |
|
|
3768 | You can disable these wrappers (to test compatibility with future |
|
|
3769 | versions) by defining C<EV_COMPAT3> to C<0> when compiling your |
|
|
3770 | sources. This has the additional advantage that you can drop the C<struct> |
|
|
3771 | from C<struct ev_loop> declarations, as libev will provide an C<ev_loop> |
|
|
3772 | typedef in that case. |
|
|
3773 | |
|
|
3774 | In some future version, the default for C<EV_COMPAT3> will become C<0>, |
|
|
3775 | and in some even more future version the compatibility code will be |
|
|
3776 | removed completely. |
3675 | |
3777 | |
3676 | =item EV_STANDALONE (h) |
3778 | =item EV_STANDALONE (h) |
3677 | |
3779 | |
3678 | Must always be C<1> if you do not use autoconf configuration, which |
3780 | Must always be C<1> if you do not use autoconf configuration, which |
3679 | keeps libev from including F<config.h>, and it also defines dummy |
3781 | keeps libev from including F<config.h>, and it also defines dummy |
… | |
… | |
4029 | The default is C<1>, unless C<EV_FEATURES> overrides it, in which case it |
4131 | The default is C<1>, unless C<EV_FEATURES> overrides it, in which case it |
4030 | will be C<0>. |
4132 | will be C<0>. |
4031 | |
4133 | |
4032 | =item EV_VERIFY |
4134 | =item EV_VERIFY |
4033 | |
4135 | |
4034 | Controls how much internal verification (see C<ev_loop_verify ()>) will |
4136 | Controls how much internal verification (see C<ev_verify ()>) will |
4035 | be done: If set to C<0>, no internal verification code will be compiled |
4137 | be done: If set to C<0>, no internal verification code will be compiled |
4036 | in. If set to C<1>, then verification code will be compiled in, but not |
4138 | in. If set to C<1>, then verification code will be compiled in, but not |
4037 | called. If set to C<2>, then the internal verification code will be |
4139 | called. If set to C<2>, then the internal verification code will be |
4038 | called once per loop, which can slow down libev. If set to C<3>, then the |
4140 | called once per loop, which can slow down libev. If set to C<3>, then the |
4039 | verification code will be called very frequently, which will slow down |
4141 | verification code will be called very frequently, which will slow down |
… | |
… | |
4254 | userdata *u = ev_userdata (EV_A); |
4356 | userdata *u = ev_userdata (EV_A); |
4255 | pthread_mutex_lock (&u->lock); |
4357 | pthread_mutex_lock (&u->lock); |
4256 | } |
4358 | } |
4257 | |
4359 | |
4258 | The event loop thread first acquires the mutex, and then jumps straight |
4360 | The event loop thread first acquires the mutex, and then jumps straight |
4259 | into C<ev_loop>: |
4361 | into C<ev_run>: |
4260 | |
4362 | |
4261 | void * |
4363 | void * |
4262 | l_run (void *thr_arg) |
4364 | l_run (void *thr_arg) |
4263 | { |
4365 | { |
4264 | struct ev_loop *loop = (struct ev_loop *)thr_arg; |
4366 | struct ev_loop *loop = (struct ev_loop *)thr_arg; |
4265 | |
4367 | |
4266 | l_acquire (EV_A); |
4368 | l_acquire (EV_A); |
4267 | pthread_setcanceltype (PTHREAD_CANCEL_ASYNCHRONOUS, 0); |
4369 | pthread_setcanceltype (PTHREAD_CANCEL_ASYNCHRONOUS, 0); |
4268 | ev_loop (EV_A_ 0); |
4370 | ev_run (EV_A_ 0); |
4269 | l_release (EV_A); |
4371 | l_release (EV_A); |
4270 | |
4372 | |
4271 | return 0; |
4373 | return 0; |
4272 | } |
4374 | } |
4273 | |
4375 | |
… | |
… | |
4325 | |
4427 | |
4326 | =head3 COROUTINES |
4428 | =head3 COROUTINES |
4327 | |
4429 | |
4328 | Libev is very accommodating to coroutines ("cooperative threads"): |
4430 | Libev is very accommodating to coroutines ("cooperative threads"): |
4329 | libev fully supports nesting calls to its functions from different |
4431 | libev fully supports nesting calls to its functions from different |
4330 | coroutines (e.g. you can call C<ev_loop> on the same loop from two |
4432 | coroutines (e.g. you can call C<ev_run> on the same loop from two |
4331 | different coroutines, and switch freely between both coroutines running |
4433 | different coroutines, and switch freely between both coroutines running |
4332 | the loop, as long as you don't confuse yourself). The only exception is |
4434 | the loop, as long as you don't confuse yourself). The only exception is |
4333 | that you must not do this from C<ev_periodic> reschedule callbacks. |
4435 | that you must not do this from C<ev_periodic> reschedule callbacks. |
4334 | |
4436 | |
4335 | Care has been taken to ensure that libev does not keep local state inside |
4437 | Care has been taken to ensure that libev does not keep local state inside |
4336 | C<ev_loop>, and other calls do not usually allow for coroutine switches as |
4438 | C<ev_run>, and other calls do not usually allow for coroutine switches as |
4337 | they do not call any callbacks. |
4439 | they do not call any callbacks. |
4338 | |
4440 | |
4339 | =head2 COMPILER WARNINGS |
4441 | =head2 COMPILER WARNINGS |
4340 | |
4442 | |
4341 | Depending on your compiler and compiler settings, you might get no or a |
4443 | Depending on your compiler and compiler settings, you might get no or a |
… | |
… | |
4626 | watchers. |
4728 | watchers. |
4627 | |
4729 | |
4628 | =item C<double> must hold a time value in seconds with enough accuracy |
4730 | =item C<double> must hold a time value in seconds with enough accuracy |
4629 | |
4731 | |
4630 | The type C<double> is used to represent timestamps. It is required to |
4732 | The type C<double> is used to represent timestamps. It is required to |
4631 | have at least 51 bits of mantissa (and 9 bits of exponent), which is good |
4733 | have at least 51 bits of mantissa (and 9 bits of exponent), which is |
4632 | enough for at least into the year 4000. This requirement is fulfilled by |
4734 | good enough for at least into the year 4000 with millisecond accuracy |
|
|
4735 | (the design goal for libev). This requirement is overfulfilled by |
4633 | implementations implementing IEEE 754, which is basically all existing |
4736 | implementations using IEEE 754, which is basically all existing ones. With |
4634 | ones. With IEEE 754 doubles, you get microsecond accuracy until at least |
4737 | IEEE 754 doubles, you get microsecond accuracy until at least 2200. |
4635 | 2200. |
|
|
4636 | |
4738 | |
4637 | =back |
4739 | =back |
4638 | |
4740 | |
4639 | If you know of other additional requirements drop me a note. |
4741 | If you know of other additional requirements drop me a note. |
4640 | |
4742 | |
… | |
… | |
4718 | compatibility, so most programs should still compile. Those might be |
4820 | compatibility, so most programs should still compile. Those might be |
4719 | removed in later versions of libev, so better update early than late. |
4821 | removed in later versions of libev, so better update early than late. |
4720 | |
4822 | |
4721 | =over 4 |
4823 | =over 4 |
4722 | |
4824 | |
4723 | =item C<ev_loop_count> renamed to C<ev_iteration> |
4825 | =item function/symbol renames |
4724 | |
4826 | |
4725 | =item C<ev_loop_depth> renamed to C<ev_depth> |
4827 | A number of functions and symbols have been renamed: |
4726 | |
4828 | |
4727 | =item C<ev_loop_verify> renamed to C<ev_verify> |
4829 | ev_loop => ev_run |
|
|
4830 | EVLOOP_NONBLOCK => EVRUN_NOWAIT |
|
|
4831 | EVLOOP_ONESHOT => EVRUN_ONCE |
|
|
4832 | |
|
|
4833 | ev_unloop => ev_break |
|
|
4834 | EVUNLOOP_CANCEL => EVBREAK_CANCEL |
|
|
4835 | EVUNLOOP_ONE => EVBREAK_ONE |
|
|
4836 | EVUNLOOP_ALL => EVBREAK_ALL |
|
|
4837 | |
|
|
4838 | EV_TIMEOUT => EV_TIMER |
|
|
4839 | |
|
|
4840 | ev_loop_count => ev_iteration |
|
|
4841 | ev_loop_depth => ev_depth |
|
|
4842 | ev_loop_verify => ev_verify |
4728 | |
4843 | |
4729 | Most functions working on C<struct ev_loop> objects don't have an |
4844 | Most functions working on C<struct ev_loop> objects don't have an |
4730 | C<ev_loop_> prefix, so it was removed. Note that C<ev_loop_fork> is |
4845 | C<ev_loop_> prefix, so it was removed; C<ev_loop>, C<ev_unloop> and |
|
|
4846 | associated constants have been renamed to not collide with the C<struct |
|
|
4847 | ev_loop> anymore and C<EV_TIMER> now follows the same naming scheme |
|
|
4848 | as all other watcher types. Note that C<ev_loop_fork> is still called |
4731 | still called C<ev_loop_fork> because it would otherwise clash with the |
4849 | C<ev_loop_fork> because it would otherwise clash with the C<ev_fork> |
4732 | C<ev_fork> typedef. |
4850 | typedef. |
4733 | |
4851 | |
4734 | =item C<EV_TIMEOUT> renamed to C<EV_TIMER> in C<revents> |
4852 | =item C<EV_COMPAT3> backwards compatibility mechanism |
4735 | |
4853 | |
4736 | This is a simple rename - all other watcher types use their name |
4854 | The backward compatibility mechanism can be controlled by |
4737 | as revents flag, and now C<ev_timer> does, too. |
4855 | C<EV_COMPAT3>. See L<PREPROCESSOR SYMBOLS/MACROS> in the L<EMBEDDING> |
4738 | |
4856 | section. |
4739 | Both C<EV_TIMER> and C<EV_TIMEOUT> symbols were present in 3.x versions |
|
|
4740 | and continue to be present for the foreseeable future, so this is mostly a |
|
|
4741 | documentation change. |
|
|
4742 | |
4857 | |
4743 | =item C<EV_MINIMAL> mechanism replaced by C<EV_FEATURES> |
4858 | =item C<EV_MINIMAL> mechanism replaced by C<EV_FEATURES> |
4744 | |
4859 | |
4745 | The preprocessor symbol C<EV_MINIMAL> has been replaced by a different |
4860 | The preprocessor symbol C<EV_MINIMAL> has been replaced by a different |
4746 | mechanism, C<EV_FEATURES>. Programs using C<EV_MINIMAL> usually compile |
4861 | mechanism, C<EV_FEATURES>. Programs using C<EV_MINIMAL> usually compile |