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Revision 1.306 by root, Mon Oct 18 07:36:05 2010 UTC vs.
Revision 1.312 by root, Thu Oct 21 15:14:49 2010 UTC

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
297An event loop is described by a C<struct ev_loop *> (the C<struct> 297An event loop is described by a C<struct ev_loop *> (the C<struct> is
298is I<not> optional in this case, as there is also an C<ev_loop> 298I<not> optional in this case unless libev 3 compatibility is disabled, as
299I<function>). 299libev 3 had an C<ev_loop> function colliding with the struct name).
300 300
301The library knows two types of such loops, the I<default> loop, which 301The library knows two types of such loops, the I<default> loop, which
302supports signals and child events, and dynamically created loops which do 302supports signals and child events, and dynamically created event loops
303not. 303which 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
606Like C<ev_default_destroy>, but destroys an event loop created by an 606Like C<ev_default_destroy>, but destroys an event loop created by an
607earlier call to C<ev_loop_new>. 607earlier call to C<ev_loop_new>.
608 608
609=item ev_default_fork () 609=item ev_default_fork ()
610 610
611This function sets a flag that causes subsequent C<ev_loop> iterations 611This function sets a flag that causes subsequent C<ev_run> iterations
612to reinitialise the kernel state for backends that have one. Despite the 612to reinitialise the kernel state for backends that have one. Despite the
613name, you can call it anytime, but it makes most sense after forking, in 613name, you can call it anytime, but it makes most sense after forking, in
614the child process (or both child and parent, but that again makes little 614the child process (or both child and parent, but that again makes little
615sense). You I<must> call it in the child before using any of the libev 615sense). You I<must> call it in the child before using any of the libev
616functions, and it will only take effect at the next C<ev_loop> iteration. 616functions, and it will only take effect at the next C<ev_run> iteration.
617 617
618Again, you I<have> to call it on I<any> loop that you want to re-use after 618Again, you I<have> to call it on I<any> loop that you want to re-use after
619a fork, I<even if you do not plan to use the loop in the parent>. This is 619a fork, I<even if you do not plan to use the loop in the parent>. This is
620because some kernel interfaces *cough* I<kqueue> *cough* do funny things 620because some kernel interfaces *cough* I<kqueue> *cough* do funny things
621during fork. 621during fork.
622 622
623On the other hand, you only need to call this function in the child 623On the other hand, you only need to call this function in the child
624process if and only if you want to use the event loop in the child. If you 624process if and only if you want to use the event loop in the child. If
625just fork+exec or create a new loop in the child, you don't have to call 625you just fork+exec or create a new loop in the child, you don't have to
626it at all. 626call it at all (in fact, C<epoll> is so badly broken that it makes a
627difference, but libev will usually detect this case on its own and do a
628costly reset of the backend).
627 629
628The function itself is quite fast and it's usually not a problem to call 630The function itself is quite fast and it's usually not a problem to call
629it just in case after a fork. To make this easy, the function will fit in 631it just in case after a fork. To make this easy, the function will fit in
630quite nicely into a call to C<pthread_atfork>: 632quite nicely into a call to C<pthread_atfork>:
631 633
643Returns true when the given loop is, in fact, the default loop, and false 645Returns true when the given loop is, in fact, the default loop, and false
644otherwise. 646otherwise.
645 647
646=item unsigned int ev_iteration (loop) 648=item unsigned int ev_iteration (loop)
647 649
648Returns the current iteration count for the loop, which is identical to 650Returns the current iteration count for the event loop, which is identical
649the number of times libev did poll for new events. It starts at C<0> and 651to the number of times libev did poll for new events. It starts at C<0>
650happily wraps around with enough iterations. 652and happily wraps around with enough iterations.
651 653
652This value can sometimes be useful as a generation counter of sorts (it 654This 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
654C<ev_prepare> and C<ev_check> calls - and is incremented between the 656C<ev_prepare> and C<ev_check> calls - and is incremented between the
655prepare and check phases. 657prepare and check phases.
656 658
657=item unsigned int ev_depth (loop) 659=item unsigned int ev_depth (loop)
658 660
659Returns the number of times C<ev_loop> was entered minus the number of 661Returns the number of times C<ev_run> was entered minus the number of
660times C<ev_loop> was exited, in other words, the recursion depth. 662times C<ev_run> was exited, in other words, the recursion depth.
661 663
662Outside C<ev_loop>, this number is zero. In a callback, this number is 664Outside C<ev_run>, this number is zero. In a callback, this number is
663C<1>, unless C<ev_loop> was invoked recursively (or from another thread), 665C<1>, unless C<ev_run> was invoked recursively (or from another thread),
664in which case it is higher. 666in which case it is higher.
665 667
666Leaving C<ev_loop> abnormally (setjmp/longjmp, cancelling the thread 668Leaving C<ev_run> abnormally (setjmp/longjmp, cancelling the thread
667etc.), doesn't count as "exit" - consider this as a hint to avoid such 669etc.), doesn't count as "exit" - consider this as a hint to avoid such
668ungentleman behaviour unless it's really convenient. 670ungentleman-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
672Returns one of the C<EVBACKEND_*> flags indicating the event backend in 674Returns one of the C<EVBACKEND_*> flags indicating the event backend in
673use. 675use.
682 684
683=item ev_now_update (loop) 685=item ev_now_update (loop)
684 686
685Establishes the current time by querying the kernel, updating the time 687Establishes the current time by querying the kernel, updating the time
686returned by C<ev_now ()> in the progress. This is a costly operation and 688returned by C<ev_now ()> in the progress. This is a costly operation and
687is usually done automatically within C<ev_loop ()>. 689is usually done automatically within C<ev_run ()>.
688 690
689This function is rarely useful, but when some event callback runs for a 691This function is rarely useful, but when some event callback runs for a
690very long time without entering the event loop, updating libev's idea of 692very long time without entering the event loop, updating libev's idea of
691the current time is a good idea. 693the 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
699These two functions suspend and resume a loop, for use when the loop is 701These two functions suspend and resume an event loop, for use when the
700not used for a while and timeouts should not be processed. 702loop is not used for a while and timeouts should not be processed.
701 703
702A typical use case would be an interactive program such as a game: When 704A typical use case would be an interactive program such as a game: When
703the user presses C<^Z> to suspend the game and resumes it an hour later it 705the user presses C<^Z> to suspend the game and resumes it an hour later it
704would be best to handle timeouts as if no time had actually passed while 706would be best to handle timeouts as if no time had actually passed while
705the program was suspended. This can be achieved by calling C<ev_suspend> 707the program was suspended. This can be achieved by calling C<ev_suspend>
716without a previous call to C<ev_suspend>. 718without a previous call to C<ev_suspend>.
717 719
718Calling C<ev_suspend>/C<ev_resume> has the side effect of updating the 720Calling C<ev_suspend>/C<ev_resume> has the side effect of updating the
719event loop time (see C<ev_now_update>). 721event 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
723Finally, this is it, the event handler. This function usually is called 725Finally, this is it, the event handler. This function usually is called
724after you have initialised all your watchers and you want to start 726after you have initialised all your watchers and you want to start
725handling events. 727handling events. It will ask the operating system for any new events, call
728the watcher callbacks, an then repeat the whole process indefinitely: This
729is why event loops are called I<loops>.
726 730
727If the flags argument is specified as C<0>, it will not return until 731If the flags argument is specified as C<0>, it will keep handling events
728either no event watchers are active anymore or C<ev_unloop> was called. 732until either no event watchers are active anymore or C<ev_break> was
733called.
729 734
730Please note that an explicit C<ev_unloop> is usually better than 735Please note that an explicit C<ev_break> is usually better than
731relying on all watchers to be stopped when deciding when a program has 736relying on all watchers to be stopped when deciding when a program has
732finished (especially in interactive programs), but having a program 737finished (especially in interactive programs), but having a program
733that automatically loops as long as it has to and no longer by virtue 738that automatically loops as long as it has to and no longer by virtue
734of relying on its watchers stopping correctly, that is truly a thing of 739of relying on its watchers stopping correctly, that is truly a thing of
735beauty. 740beauty.
736 741
737A flags value of C<EVLOOP_NONBLOCK> will look for new events, will handle 742A flags value of C<EVRUN_NOWAIT> will look for new events, will handle
738those events and any already outstanding ones, but will not block your 743those events and any already outstanding ones, but will not wait and
739process in case there are no events and will return after one iteration of 744block your process in case there are no events and will return after one
740the loop. 745iteration of the loop. This is sometimes useful to poll and handle new
746events while doing lengthy calculations, to keep the program responsive.
741 747
742A flags value of C<EVLOOP_ONESHOT> will look for new events (waiting if 748A flags value of C<EVRUN_ONCE> will look for new events (waiting if
743necessary) and will handle those and any already outstanding ones. It 749necessary) and will handle those and any already outstanding ones. It
744will block your process until at least one new event arrives (which could 750will block your process until at least one new event arrives (which could
745be an event internal to libev itself, so there is no guarantee that a 751be an event internal to libev itself, so there is no guarantee that a
746user-registered callback will be called), and will return after one 752user-registered callback will be called), and will return after one
747iteration of the loop. 753iteration of the loop.
748 754
749This is useful if you are waiting for some external event in conjunction 755This is useful if you are waiting for some external event in conjunction
750with something not expressible using other libev watchers (i.e. "roll your 756with something not expressible using other libev watchers (i.e. "roll your
751own C<ev_loop>"). However, a pair of C<ev_prepare>/C<ev_check> watchers is 757own C<ev_run>"). However, a pair of C<ev_prepare>/C<ev_check> watchers is
752usually a better approach for this kind of thing. 758usually a better approach for this kind of thing.
753 759
754Here are the gory details of what C<ev_loop> does: 760Here 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
782Example: Queue some jobs and then loop until no events are outstanding 797Example: Queue some jobs and then loop until no events are outstanding
783anymore. 798anymore.
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
792Can be used to make a call to C<ev_loop> return early (but only after it 807Can be used to make a call to C<ev_run> return early (but only after it
793has processed all outstanding events). The C<how> argument must be either 808has processed all outstanding events). The C<how> argument must be either
794C<EVUNLOOP_ONE>, which will make the innermost C<ev_loop> call return, or 809C<EVBREAK_ONE>, which will make the innermost C<ev_run> call return, or
795C<EVUNLOOP_ALL>, which will make all nested C<ev_loop> calls return. 810C<EVBREAK_ALL>, which will make all nested C<ev_run> calls return.
796 811
797This "unloop state" will be cleared when entering C<ev_loop> again. 812This "unloop state" will be cleared when entering C<ev_run> again.
798 813
799It is safe to call C<ev_unloop> from outside any C<ev_loop> calls. 814It 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
805Ref/unref can be used to add or remove a reference count on the event 820Ref/unref can be used to add or remove a reference count on the event
806loop: Every watcher keeps one reference, and as long as the reference 821loop: Every watcher keeps one reference, and as long as the reference
807count is nonzero, C<ev_loop> will not return on its own. 822count is nonzero, C<ev_run> will not return on its own.
808 823
809This is useful when you have a watcher that you never intend to 824This is useful when you have a watcher that you never intend to
810unregister, but that nevertheless should not keep C<ev_loop> from 825unregister, but that nevertheless should not keep C<ev_run> from
811returning. In such a case, call C<ev_unref> after starting, and C<ev_ref> 826returning. In such a case, call C<ev_unref> after starting, and C<ev_ref>
812before stopping it. 827before stopping it.
813 828
814As an example, libev itself uses this for its internal signal pipe: It 829As an example, libev itself uses this for its internal signal pipe: It
815is not visible to the libev user and should not keep C<ev_loop> from 830is not visible to the libev user and should not keep C<ev_run> from
816exiting if no event watchers registered by it are active. It is also an 831exiting if no event watchers registered by it are active. It is also an
817excellent way to do this for generic recurring timers or from within 832excellent way to do this for generic recurring timers or from within
818third-party libraries. Just remember to I<unref after start> and I<ref 833third-party libraries. Just remember to I<unref after start> and I<ref
819before stop> (but only if the watcher wasn't active before, or was active 834before stop> (but only if the watcher wasn't active before, or was active
820before, respectively. Note also that libev might stop watchers itself 835before, 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>
822in the callback). 837in the callback).
823 838
824Example: Create a signal watcher, but keep it from keeping C<ev_loop> 839Example: Create a signal watcher, but keep it from keeping C<ev_run>
825running when nothing else is active. 840running 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
896This call will simply invoke all pending watchers while resetting their 911This call will simply invoke all pending watchers while resetting their
897pending state. Normally, C<ev_loop> does this automatically when required, 912pending state. Normally, C<ev_run> does this automatically when required,
898but when overriding the invoke callback this call comes handy. 913but 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
902Returns the number of pending watchers - zero indicates that no watchers 917Returns the number of pending watchers - zero indicates that no watchers
903are pending. 918are 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
907This overrides the invoke pending functionality of the loop: Instead of 922This overrides the invoke pending functionality of the loop: Instead of
908invoking all pending watchers when there are any, C<ev_loop> will call 923invoking all pending watchers when there are any, C<ev_run> will call
909this callback instead. This is useful, for example, when you want to 924this callback instead. This is useful, for example, when you want to
910invoke the actual watchers inside another context (another thread etc.). 925invoke the actual watchers inside another context (another thread etc.).
911 926
912If you want to reset the callback, use C<ev_invoke_pending> as new 927If you want to reset the callback, use C<ev_invoke_pending> as new
913callback. 928callback.
916 931
917Sometimes you want to share the same loop between multiple threads. This 932Sometimes you want to share the same loop between multiple threads. This
918can be done relatively simply by putting mutex_lock/unlock calls around 933can be done relatively simply by putting mutex_lock/unlock calls around
919each call to a libev function. 934each call to a libev function.
920 935
921However, C<ev_loop> can run an indefinite time, so it is not feasible to 936However, C<ev_run> can run an indefinite time, so it is not feasible
922wait for it to return. One way around this is to wake up the loop via 937to wait for it to return. One way around this is to wake up the event
923C<ev_unloop> and C<av_async_send>, another way is to set these I<release> 938loop via C<ev_break> and C<av_async_send>, another way is to set these
924and I<acquire> callbacks on the loop. 939I<release> and I<acquire> callbacks on the loop.
925 940
926When set, then C<release> will be called just before the thread is 941When set, then C<release> will be called just before the thread is
927suspended waiting for new events, and C<acquire> is called just 942suspended waiting for new events, and C<acquire> is called just
928afterwards. 943afterwards.
929 944
932 947
933While event loop modifications are allowed between invocations of 948While event loop modifications are allowed between invocations of
934C<release> and C<acquire> (that's their only purpose after all), no 949C<release> and C<acquire> (that's their only purpose after all), no
935modifications done will affect the event loop, i.e. adding watchers will 950modifications done will affect the event loop, i.e. adding watchers will
936have no effect on the set of file descriptors being watched, or the time 951have no effect on the set of file descriptors being watched, or the time
937waited. Use an C<ev_async> watcher to wake up C<ev_loop> when you want it 952waited. Use an C<ev_async> watcher to wake up C<ev_run> when you want it
938to take note of any changes you made. 953to take note of any changes you made.
939 954
940In theory, threads executing C<ev_loop> will be async-cancel safe between 955In theory, threads executing C<ev_run> will be async-cancel safe between
941invocations of C<release> and C<acquire>. 956invocations of C<release> and C<acquire>.
942 957
943See also the locking example in the C<THREADS> section later in this 958See also the locking example in the C<THREADS> section later in this
944document. 959document.
945 960
954These two functions can be used to associate arbitrary data with a loop, 969These two functions can be used to associate arbitrary data with a loop,
955and are intended solely for the C<invoke_pending_cb>, C<release> and 970and are intended solely for the C<invoke_pending_cb>, C<release> and
956C<acquire> callbacks described above, but of course can be (ab-)used for 971C<acquire> callbacks described above, but of course can be (ab-)used for
957any other purpose as well. 972any other purpose as well.
958 973
959=item ev_loop_verify (loop) 974=item ev_verify (loop)
960 975
961This function only does something when C<EV_VERIFY> support has been 976This function only does something when C<EV_VERIFY> support has been
962compiled in, which is the default for non-minimal builds. It tries to go 977compiled in, which is the default for non-minimal builds. It tries to go
963through all internal structures and checks them for validity. If anything 978through all internal structures and checks them for validity. If anything
964is found to be inconsistent, it will print an error message to standard 979is found to be inconsistent, it will print an error message to standard
975 990
976In the following description, uppercase C<TYPE> in names stands for the 991In the following description, uppercase C<TYPE> in names stands for the
977watcher type, e.g. C<ev_TYPE_start> can mean C<ev_timer_start> for timer 992watcher type, e.g. C<ev_TYPE_start> can mean C<ev_timer_start> for timer
978watchers and C<ev_io_start> for I/O watchers. 993watchers and C<ev_io_start> for I/O watchers.
979 994
980A watcher is a structure that you create and register to record your 995A watcher is an opaque structure that you allocate and register to record
981interest in some event. For instance, if you want to wait for STDIN to 996your interest in some event. To make a concrete example, imagine you want
982become readable, you would create an C<ev_io> watcher for that: 997to wait for STDIN to become readable, you would create an C<ev_io> watcher
998for 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
1000As you can see, you are responsible for allocating the memory for your 1016As you can see, you are responsible for allocating the memory for your
1001watcher structures (and it is I<usually> a bad idea to do this on the 1017watcher structures (and it is I<usually> a bad idea to do this on the
1002stack). 1018stack).
1003 1019
1004Each watcher has an associated watcher structure (called C<struct ev_TYPE> 1020Each watcher has an associated watcher structure (called C<struct ev_TYPE>
1005or simply C<ev_TYPE>, as typedefs are provided for all watcher structs). 1021or simply C<ev_TYPE>, as typedefs are provided for all watcher structs).
1006 1022
1007Each watcher structure must be initialised by a call to C<ev_init 1023Each 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
1009callback gets invoked each time the event occurs (or, in the case of I/O 1025invoked each time the event occurs (or, in the case of I/O watchers, each
1010watchers, each time the event loop detects that the file descriptor given 1026time the event loop detects that the file descriptor given is readable
1011is readable and/or writable). 1027and/or writable).
1012 1028
1013Each watcher type further has its own C<< ev_TYPE_set (watcher *, ...) >> 1029Each watcher type further has its own C<< ev_TYPE_set (watcher *, ...) >>
1014macro to configure it, with arguments specific to the watcher type. There 1030macro to configure it, with arguments specific to the watcher type. There
1015is also a macro to combine initialisation and setting in one call: C<< 1031is also a macro to combine initialisation and setting in one call: C<<
1016ev_TYPE_init (watcher *, callback, ...) >>. 1032ev_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
1072All C<ev_prepare> watchers are invoked just I<before> C<ev_loop> starts 1088All C<ev_prepare> watchers are invoked just I<before> C<ev_run> starts
1073to gather new events, and all C<ev_check> watchers are invoked just after 1089to gather new events, and all C<ev_check> watchers are invoked just after
1074C<ev_loop> has gathered them, but before it invokes any callbacks for any 1090C<ev_run> has gathered them, but before it invokes any callbacks for any
1075received events. Callbacks of both watcher types can start and stop as 1091received events. Callbacks of both watcher types can start and stop as
1076many watchers as they want, and all of them will be taken into account 1092many 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
1078C<ev_loop> from blocking). 1094C<ev_run> from blocking).
1079 1095
1080=item C<EV_EMBED> 1096=item C<EV_EMBED>
1081 1097
1082The embedded event loop specified in the C<ev_embed> watcher needs attention. 1098The embedded event loop specified in the C<ev_embed> watcher needs attention.
1083 1099
1111example it might indicate that a fd is readable or writable, and if your 1127example it might indicate that a fd is readable or writable, and if your
1112callbacks is well-written it can just attempt the operation and cope with 1128callbacks is well-written it can just attempt the operation and cope with
1113the error from read() or write(). This will not work in multi-threaded 1129the error from read() or write(). This will not work in multi-threaded
1114programs, though, as the fd could already be closed and reused for another 1130programs, though, as the fd could already be closed and reused for another
1115thing, so beware. 1131thing, so beware.
1132
1133=back
1134
1135=head2 WATCHER STATES
1136
1137There are various watcher states mentioned throughout this manual -
1138active, pending and so on. In this section these states and the rules to
1139transition between them will be described in more detail - and while these
1140rules might look complicated, they usually do "the right thing".
1141
1142=over 4
1143
1144=item initialiased
1145
1146Before a watcher can be registered with the event looop it has to be
1147initialised. This can be done with a call to C<ev_TYPE_init>, or calls to
1148C<ev_init> followed by the watcher-specific C<ev_TYPE_set> function.
1149
1150In this state it is simply some block of memory that is suitable for use
1151in an event loop. It can be moved around, freed, reused etc. at will.
1152
1153=item started/running/active
1154
1155Once a watcher has been started with a call to C<ev_TYPE_start> it becomes
1156property of the event loop, and is actively waiting for events. While in
1157this state it cannot be accessed (except in a few documented ways), moved,
1158freed or anything else - the only legal thing is to keep a pointer to it,
1159and call libev functions on it that are documented to work on active watchers.
1160
1161=item pending
1162
1163If a watcher is active and libev determines that an event it is interested
1164in has occurred (such as a timer expiring), it will become pending. It will
1165stay in this pending state until either it is stopped or its callback is
1166about to be invoked, so it is not normally pending inside the watcher
1167callback.
1168
1169The watcher might or might not be active while it is pending (for example,
1170an expired non-repeating timer can be pending but no longer active). If it
1171is stopped, it can be freely accessed (e.g. by calling C<ev_TYPE_set>),
1172but it is still property of the event loop at this time, so cannot be
1173moved, freed or reused. And if it is active the rules described in the
1174previous item still apply.
1175
1176It is also possible to feed an event on a watcher that is not active (e.g.
1177via C<ev_feed_event>), in which case it becomes pending without being
1178active.
1179
1180=item stopped
1181
1182A watcher can be stopped implicitly by libev (in which case it might still
1183be pending), or explicitly by calling its C<ev_TYPE_stop> function. The
1184latter will clear any pending state the watcher might be in, regardless
1185of whether it was active or not, so stopping a watcher explicitly before
1186freeing it is often a good idea.
1187
1188While stopped (and not pending) the watcher is essentially in the
1189initialised state, that is it can be reused, moved, modified in any way
1190you 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
1634Timer watchers are simple relative timers that generate an event after a 1709Timer watchers are simple relative timers that generate an event after a
1643The callback is guaranteed to be invoked only I<after> its timeout has 1718The callback is guaranteed to be invoked only I<after> its timeout has
1644passed (not I<at>, so on systems with very low-resolution clocks this 1719passed (not I<at>, so on systems with very low-resolution clocks this
1645might introduce a small delay). If multiple timers become ready during the 1720might introduce a small delay). If multiple timers become ready during the
1646same loop iteration then the ones with earlier time-out values are invoked 1721same loop iteration then the ones with earlier time-out values are invoked
1647before ones of the same priority with later time-out values (but this is 1722before ones of the same priority with later time-out values (but this is
1648no longer true when a callback calls C<ev_loop> recursively). 1723no 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
1652Many real-world problems involve some kind of timeout, usually for error 1727Many real-world problems involve some kind of timeout, usually for error
1653recovery. A typical example is an HTTP request - if the other side hangs, 1728recovery. 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
1827Establishing the current time is a costly operation (it usually takes at 1902Establishing the current time is a costly operation (it usually takes at
1828least two system calls): EV therefore updates its idea of the current 1903least two system calls): EV therefore updates its idea of the current
1829time only before and after C<ev_loop> collects new events, which causes a 1904time only before and after C<ev_run> collects new events, which causes a
1830growing difference between C<ev_now ()> and C<ev_time ()> when handling 1905growing difference between C<ev_now ()> and C<ev_time ()> when handling
1831lots of events in one iteration. 1906lots of events in one iteration.
1832 1907
1833The relative timeouts are calculated relative to the C<ev_now ()> 1908The relative timeouts are calculated relative to the C<ev_now ()>
1834time. This is usually the right thing as this timestamp refers to the time 1909time. 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
1988As with timers, the callback is guaranteed to be invoked only when the 2063As with timers, the callback is guaranteed to be invoked only when the
1989point in time where it is supposed to trigger has passed. If multiple 2064point in time where it is supposed to trigger has passed. If multiple
1990timers become ready during the same loop iteration then the ones with 2065timers become ready during the same loop iteration then the ones with
1991earlier time-out values are invoked before ones with later time-out values 2066earlier 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
2235Example: Try to exit cleanly on SIGINT. 2310Example: 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
2632Prepare and check watchers are usually (but not always) used in pairs: 2707Prepare and check watchers are usually (but not always) used in pairs:
2633prepare watchers get invoked before the process blocks and check watchers 2708prepare watchers get invoked before the process blocks and check watchers
2634afterwards. 2709afterwards.
2635 2710
2636You I<must not> call C<ev_loop> or similar functions that enter 2711You I<must not> call C<ev_run> or similar functions that enter
2637the current event loop from either C<ev_prepare> or C<ev_check> 2712the current event loop from either C<ev_prepare> or C<ev_check>
2638watchers. Other loops than the current one are fine, however. The 2713watchers. Other loops than the current one are fine, however. The
2639rationale behind this is that you do not need to check for recursion in 2714rationale behind this is that you do not need to check for recursion in
2640those watchers, i.e. the sequence will always be C<ev_prepare>, blocking, 2715those watchers, i.e. the sequence will always be C<ev_prepare>, blocking,
2641C<ev_check> so if you have one watcher of each kind they will always be 2716C<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
2897if you do not want that, you need to temporarily stop the embed watcher). 2972if 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
2901Make a single, non-blocking sweep over the embedded loop. This works 2976Make a single, non-blocking sweep over the embedded loop. This works
2902similarly to C<ev_loop (embedded_loop, EVLOOP_NONBLOCK)>, but in the most 2977similarly to C<ev_run (embedded_loop, EVRUN_NOWAIT)>, but in the most
2903appropriate way for embedded loops. 2978appropriate way for embedded loops.
2904 2979
2905=item struct ev_loop *other [read-only] 2980=item struct ev_loop *other [read-only]
2906 2981
2907The embedded event loop. 2982The 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
3018In general, you cannot use an C<ev_loop> from multiple threads or other 3093In general, you cannot use an C<ev_run> from multiple threads or other
3019asynchronous sources such as signal handlers (as opposed to multiple event 3094asynchronous sources such as signal handlers (as opposed to multiple event
3020loops - those are of course safe to use in different threads). 3095loops - those are of course safe to use in different threads).
3021 3096
3022Sometimes, however, you need to wake up an event loop you do not control, 3097Sometimes, however, you need to wake up an event loop you do not control,
3023for example because it belongs to another thread. This is what C<ev_async> 3098for example because it belongs to another thread. This is what C<ev_async>
3391Associates a different C<struct ev_loop> with this watcher. You can only 3466Associates a different C<struct ev_loop> with this watcher. You can only
3392do this when the watcher is inactive (and not pending either). 3467do this when the watcher is inactive (and not pending either).
3393 3468
3394=item w->set ([arguments]) 3469=item w->set ([arguments])
3395 3470
3396Basically the same as C<ev_TYPE_set>, with the same arguments. Must be 3471Basically the same as C<ev_TYPE_set>, with the same arguments. Either this
3397called at least once. Unlike the C counterpart, an active watcher gets 3472method or a suitable start method must be called at least once. Unlike the
3398automatically stopped and restarted when reconfiguring it with this 3473C counterpart, an active watcher gets automatically stopped and restarted
3399method. 3474when reconfiguring it with this method.
3400 3475
3401=item w->start () 3476=item w->start ()
3402 3477
3403Starts the watcher. Note that there is no C<loop> argument, as the 3478Starts the watcher. Note that there is no C<loop> argument, as the
3404constructor already stores the event loop. 3479constructor already stores the event loop.
3405 3480
3481=item w->start ([arguments])
3482
3483Instead of calling C<set> and C<start> methods separately, it is often
3484convenient to wrap them in one call. Uses the same type of arguments as
3485the configure C<set> method of the watcher.
3486
3406=item w->stop () 3487=item w->stop ()
3407 3488
3408Stops the watcher if it is active. Again, no C<loop> argument. 3489Stops 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
3427Example: Define a class with an IO and idle watcher, start one of them in 3508Example: Define a class with two I/O and idle watchers, start the I/O
3428the constructor. 3509watchers 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
3519loop argument"). The C<EV_A> form is used when this is the sole argument, 3605loop argument"). The C<EV_A> form is used when this is the sole argument,
3520C<EV_A_> is used when other arguments are following. Example: 3606C<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
3526It assumes the variable C<loop> of type C<struct ev_loop *> is in scope, 3612It assumes the variable C<loop> of type C<struct ev_loop *> is in scope,
3527which is often provided by the following macro. 3613which 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
3578Libev can (and often is) directly embedded into host 3664Libev can (and often is) directly embedded into host
3579applications. Examples of applications that embed it include the Deliantra 3665applications. Examples of applications that embed it include the Deliantra
3670to a compiled library. All other symbols change the ABI, which means all 3756to a compiled library. All other symbols change the ABI, which means all
3671users of libev and the libev code itself must be compiled with compatible 3757users of libev and the libev code itself must be compiled with compatible
3672settings. 3758settings.
3673 3759
3674=over 4 3760=over 4
3761
3762=item EV_COMPAT3 (h)
3763
3764Backwards compatibility is a major concern for libev. This is why this
3765release of libev comes with wrappers for the functions and symbols that
3766have been renamed between libev version 3 and 4.
3767
3768You can disable these wrappers (to test compatibility with future
3769versions) by defining C<EV_COMPAT3> to C<0> when compiling your
3770sources. This has the additional advantage that you can drop the C<struct>
3771from C<struct ev_loop> declarations, as libev will provide an C<ev_loop>
3772typedef in that case.
3773
3774In some future version, the default for C<EV_COMPAT3> will become C<0>,
3775and in some even more future version the compatibility code will be
3776removed completely.
3675 3777
3676=item EV_STANDALONE (h) 3778=item EV_STANDALONE (h)
3677 3779
3678Must always be C<1> if you do not use autoconf configuration, which 3780Must always be C<1> if you do not use autoconf configuration, which
3679keeps libev from including F<config.h>, and it also defines dummy 3781keeps libev from including F<config.h>, and it also defines dummy
4029The default is C<1>, unless C<EV_FEATURES> overrides it, in which case it 4131The default is C<1>, unless C<EV_FEATURES> overrides it, in which case it
4030will be C<0>. 4132will be C<0>.
4031 4133
4032=item EV_VERIFY 4134=item EV_VERIFY
4033 4135
4034Controls how much internal verification (see C<ev_loop_verify ()>) will 4136Controls how much internal verification (see C<ev_verify ()>) will
4035be done: If set to C<0>, no internal verification code will be compiled 4137be done: If set to C<0>, no internal verification code will be compiled
4036in. If set to C<1>, then verification code will be compiled in, but not 4138in. If set to C<1>, then verification code will be compiled in, but not
4037called. If set to C<2>, then the internal verification code will be 4139called. If set to C<2>, then the internal verification code will be
4038called once per loop, which can slow down libev. If set to C<3>, then the 4140called once per loop, which can slow down libev. If set to C<3>, then the
4039verification code will be called very frequently, which will slow down 4141verification 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
4258The event loop thread first acquires the mutex, and then jumps straight 4360The event loop thread first acquires the mutex, and then jumps straight
4259into C<ev_loop>: 4361into 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
4328Libev is very accommodating to coroutines ("cooperative threads"): 4430Libev is very accommodating to coroutines ("cooperative threads"):
4329libev fully supports nesting calls to its functions from different 4431libev fully supports nesting calls to its functions from different
4330coroutines (e.g. you can call C<ev_loop> on the same loop from two 4432coroutines (e.g. you can call C<ev_run> on the same loop from two
4331different coroutines, and switch freely between both coroutines running 4433different coroutines, and switch freely between both coroutines running
4332the loop, as long as you don't confuse yourself). The only exception is 4434the loop, as long as you don't confuse yourself). The only exception is
4333that you must not do this from C<ev_periodic> reschedule callbacks. 4435that you must not do this from C<ev_periodic> reschedule callbacks.
4334 4436
4335Care has been taken to ensure that libev does not keep local state inside 4437Care has been taken to ensure that libev does not keep local state inside
4336C<ev_loop>, and other calls do not usually allow for coroutine switches as 4438C<ev_run>, and other calls do not usually allow for coroutine switches as
4337they do not call any callbacks. 4439they do not call any callbacks.
4338 4440
4339=head2 COMPILER WARNINGS 4441=head2 COMPILER WARNINGS
4340 4442
4341Depending on your compiler and compiler settings, you might get no or a 4443Depending on your compiler and compiler settings, you might get no or a
4626watchers. 4728watchers.
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
4630The type C<double> is used to represent timestamps. It is required to 4732The type C<double> is used to represent timestamps. It is required to
4631have at least 51 bits of mantissa (and 9 bits of exponent), which is good 4733have at least 51 bits of mantissa (and 9 bits of exponent), which is
4632enough for at least into the year 4000. This requirement is fulfilled by 4734good enough for at least into the year 4000 with millisecond accuracy
4735(the design goal for libev). This requirement is overfulfilled by
4633implementations implementing IEEE 754, which is basically all existing 4736implementations using IEEE 754, which is basically all existing ones. With
4634ones. With IEEE 754 doubles, you get microsecond accuracy until at least 4737IEEE 754 doubles, you get microsecond accuracy until at least 2200.
46352200.
4636 4738
4637=back 4739=back
4638 4740
4639If you know of other additional requirements drop me a note. 4741If you know of other additional requirements drop me a note.
4640 4742
4718compatibility, so most programs should still compile. Those might be 4820compatibility, so most programs should still compile. Those might be
4719removed in later versions of libev, so better update early than late. 4821removed 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> 4827A 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
4729Most functions working on C<struct ev_loop> objects don't have an 4844Most functions working on C<struct ev_loop> objects don't have an
4730C<ev_loop_> prefix, so it was removed. Note that C<ev_loop_fork> is 4845C<ev_loop_> prefix, so it was removed; C<ev_loop>, C<ev_unloop> and
4846associated constants have been renamed to not collide with the C<struct
4847ev_loop> anymore and C<EV_TIMER> now follows the same naming scheme
4848as all other watcher types. Note that C<ev_loop_fork> is still called
4731still called C<ev_loop_fork> because it would otherwise clash with the 4849C<ev_loop_fork> because it would otherwise clash with the C<ev_fork>
4732C<ev_fork> typedef. 4850typedef.
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
4736This is a simple rename - all other watcher types use their name 4854The backward compatibility mechanism can be controlled by
4737as revents flag, and now C<ev_timer> does, too. 4855C<EV_COMPAT3>. See L<PREPROCESSOR SYMBOLS/MACROS> in the L<EMBEDDING>
4738 4856section.
4739Both C<EV_TIMER> and C<EV_TIMEOUT> symbols were present in 3.x versions
4740and continue to be present for the foreseeable future, so this is mostly a
4741documentation 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
4745The preprocessor symbol C<EV_MINIMAL> has been replaced by a different 4860The preprocessor symbol C<EV_MINIMAL> has been replaced by a different
4746mechanism, C<EV_FEATURES>. Programs using C<EV_MINIMAL> usually compile 4861mechanism, C<EV_FEATURES>. Programs using C<EV_MINIMAL> usually compile

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