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Comparing libev/ev.pod (file contents):
Revision 1.433 by root, Fri May 2 07:05:42 2014 UTC vs.
Revision 1.437 by root, Sun Oct 11 15:55:48 2015 UTC

… …
416GNU/Linux system for example, C<getpid> is actually a simple 5-insn sequence 416GNU/Linux system for example, C<getpid> is actually a simple 5-insn sequence
417without a system call and thus I<very> fast, but my GNU/Linux system also has 417without a system call and thus I<very> fast, but my GNU/Linux system also has
418C<pthread_atfork> which is even faster). 418C<pthread_atfork> which is even faster).
419 419
420The big advantage of this flag is that you can forget about fork (and 420The big advantage of this flag is that you can forget about fork (and
421forget about forgetting to tell libev about forking) when you use this 421forget about forgetting to tell libev about forking, although you still
422flag. 422have to ignore C<SIGPIPE>) when you use this flag.
423 423
424This flag setting cannot be overridden or specified in the C<LIBEV_FLAGS> 424This flag setting cannot be overridden or specified in the C<LIBEV_FLAGS>
425environment variable. 425environment variable.
426 426
427=item C<EVFLAG_NOINOTIFY> 427=item C<EVFLAG_NOINOTIFY>
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688to reinitialise the kernel state for backends that have one. Despite 688to reinitialise the kernel state for backends that have one. Despite
689the name, you can call it anytime you are allowed to start or stop 689the name, you can call it anytime you are allowed to start or stop
690watchers (except inside an C<ev_prepare> callback), but it makes most 690watchers (except inside an C<ev_prepare> callback), but it makes most
691sense after forking, in the child process. You I<must> call it (or use 691sense after forking, in the child process. You I<must> call it (or use
692C<EVFLAG_FORKCHECK>) in the child before resuming or calling C<ev_run>. 692C<EVFLAG_FORKCHECK>) in the child before resuming or calling C<ev_run>.
693
694In addition, if you want to reuse a loop (via this function or
695C<EVFLAG_FORKCHECK>), you I<also> have to ignore C<SIGPIPE>.
693 696
694Again, you I<have> to call it on I<any> loop that you want to re-use after 697Again, you I<have> to call it on I<any> loop that you want to re-use after
695a fork, I<even if you do not plan to use the loop in the parent>. This is 698a fork, I<even if you do not plan to use the loop in the parent>. This is
696because some kernel interfaces *cough* I<kqueue> *cough* do funny things 699because some kernel interfaces *cough* I<kqueue> *cough* do funny things
697during fork. 700during fork.
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2029 2032
2030The relative timeouts are calculated relative to the C<ev_now ()> 2033The relative timeouts are calculated relative to the C<ev_now ()>
2031time. This is usually the right thing as this timestamp refers to the time 2034time. This is usually the right thing as this timestamp refers to the time
2032of the event triggering whatever timeout you are modifying/starting. If 2035of the event triggering whatever timeout you are modifying/starting. If
2033you suspect event processing to be delayed and you I<need> to base the 2036you suspect event processing to be delayed and you I<need> to base the
2034timeout on the current time, use something like this to adjust for this: 2037timeout on the current time, use something like the following to adjust
2038for it:
2035 2039
2036 ev_timer_set (&timer, after + ev_now () - ev_time (), 0.); 2040 ev_timer_set (&timer, after + (ev_time () - ev_now ()), 0.);
2037 2041
2038If the event loop is suspended for a long time, you can also force an 2042If the event loop is suspended for a long time, you can also force an
2039update of the time returned by C<ev_now ()> by calling C<ev_now_update 2043update of the time returned by C<ev_now ()> by calling C<ev_now_update
2040()>. 2044()>, although that will push the event time of all outstanding events
2045further into the future.
2041 2046
2042=head3 The special problem of unsynchronised clocks 2047=head3 The special problem of unsynchronised clocks
2043 2048
2044Modern systems have a variety of clocks - libev itself uses the normal 2049Modern systems have a variety of clocks - libev itself uses the normal
2045"wall clock" clock and, if available, the monotonic clock (to avoid time 2050"wall clock" clock and, if available, the monotonic clock (to avoid time
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3898To embed libev, see L</EMBEDDING>, but in short, it's easiest to create two 3903To embed libev, see L</EMBEDDING>, but in short, it's easiest to create two
3899files, F<my_ev.h> and F<my_ev.c> that include the respective libev files: 3904files, F<my_ev.h> and F<my_ev.c> that include the respective libev files:
3900 3905
3901 // my_ev.h 3906 // my_ev.h
3902 #define EV_CB_DECLARE(type) struct my_coro *cb; 3907 #define EV_CB_DECLARE(type) struct my_coro *cb;
3903 #define EV_CB_INVOKE(watcher) switch_to ((watcher)->cb); 3908 #define EV_CB_INVOKE(watcher) switch_to ((watcher)->cb)
3904 #include "../libev/ev.h" 3909 #include "../libev/ev.h"
3905 3910
3906 // my_ev.c 3911 // my_ev.c
3907 #define EV_H "my_ev.h" 3912 #define EV_H "my_ev.h"
3908 #include "../libev/ev.c" 3913 #include "../libev/ev.c"

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