… | |
… | |
98 | =head2 FEATURES |
98 | =head2 FEATURES |
99 | |
99 | |
100 | Libev supports C<select>, C<poll>, the Linux-specific C<epoll>, the |
100 | Libev supports C<select>, C<poll>, the Linux-specific C<epoll>, the |
101 | BSD-specific C<kqueue> and the Solaris-specific event port mechanisms |
101 | BSD-specific C<kqueue> and the Solaris-specific event port mechanisms |
102 | for file descriptor events (C<ev_io>), the Linux C<inotify> interface |
102 | for file descriptor events (C<ev_io>), the Linux C<inotify> interface |
103 | (for C<ev_stat>), relative timers (C<ev_timer>), absolute timers |
103 | (for C<ev_stat>), Linux eventfd/signalfd (for faster and cleaner |
104 | with customised rescheduling (C<ev_periodic>), synchronous signals |
104 | inter-thread wakeup (C<ev_async>)/signal handling (C<ev_signal>)) relative |
105 | (C<ev_signal>), process status change events (C<ev_child>), and event |
105 | timers (C<ev_timer>), absolute timers with customised rescheduling |
106 | watchers dealing with the event loop mechanism itself (C<ev_idle>, |
106 | (C<ev_periodic>), synchronous signals (C<ev_signal>), process status |
107 | C<ev_embed>, C<ev_prepare> and C<ev_check> watchers) as well as |
107 | change events (C<ev_child>), and event watchers dealing with the event |
108 | file watchers (C<ev_stat>) and even limited support for fork events |
108 | loop mechanism itself (C<ev_idle>, C<ev_embed>, C<ev_prepare> and |
109 | (C<ev_fork>). |
109 | C<ev_check> watchers) as well as file watchers (C<ev_stat>) and even |
|
|
110 | limited support for fork events (C<ev_fork>). |
110 | |
111 | |
111 | It also is quite fast (see this |
112 | It also is quite fast (see this |
112 | L<benchmark|http://libev.schmorp.de/bench.html> comparing it to libevent |
113 | L<benchmark|http://libev.schmorp.de/bench.html> comparing it to libevent |
113 | for example). |
114 | for example). |
114 | |
115 | |
… | |
… | |
361 | forget about forgetting to tell libev about forking) when you use this |
362 | forget about forgetting to tell libev about forking) when you use this |
362 | flag. |
363 | flag. |
363 | |
364 | |
364 | This flag setting cannot be overridden or specified in the C<LIBEV_FLAGS> |
365 | This flag setting cannot be overridden or specified in the C<LIBEV_FLAGS> |
365 | environment variable. |
366 | environment variable. |
|
|
367 | |
|
|
368 | =item C<EVFLAG_NOINOTIFY> |
|
|
369 | |
|
|
370 | When this flag is specified, then libev will not attempt to use the |
|
|
371 | I<inotify> API for it's C<ev_stat> watchers. Apart from debugging and |
|
|
372 | testing, this flag can be useful to conserve inotify file descriptors, as |
|
|
373 | otherwise each loop using C<ev_stat> watchers consumes one inotify handle. |
|
|
374 | |
|
|
375 | =item C<EVFLAG_NOSIGFD> |
|
|
376 | |
|
|
377 | When this flag is specified, then libev will not attempt to use the |
|
|
378 | I<signalfd> API for it's C<ev_signal> (and C<ev_child>) watchers. This is |
|
|
379 | probably only useful to work around any bugs in libev. Consequently, this |
|
|
380 | flag might go away once the signalfd functionality is considered stable, |
|
|
381 | so it's useful mostly in environment variables and not in program code. |
366 | |
382 | |
367 | =item C<EVBACKEND_SELECT> (value 1, portable select backend) |
383 | =item C<EVBACKEND_SELECT> (value 1, portable select backend) |
368 | |
384 | |
369 | This is your standard select(2) backend. Not I<completely> standard, as |
385 | This is your standard select(2) backend. Not I<completely> standard, as |
370 | libev tries to roll its own fd_set with no limits on the number of fds, |
386 | libev tries to roll its own fd_set with no limits on the number of fds, |
… | |
… | |
518 | |
534 | |
519 | It is definitely not recommended to use this flag. |
535 | It is definitely not recommended to use this flag. |
520 | |
536 | |
521 | =back |
537 | =back |
522 | |
538 | |
523 | If one or more of these are or'ed into the flags value, then only these |
539 | If one or more of the backend flags are or'ed into the flags value, |
524 | backends will be tried (in the reverse order as listed here). If none are |
540 | then only these backends will be tried (in the reverse order as listed |
525 | specified, all backends in C<ev_recommended_backends ()> will be tried. |
541 | here). If none are specified, all backends in C<ev_recommended_backends |
|
|
542 | ()> will be tried. |
526 | |
543 | |
527 | Example: This is the most typical usage. |
544 | Example: This is the most typical usage. |
528 | |
545 | |
529 | if (!ev_default_loop (0)) |
546 | if (!ev_default_loop (0)) |
530 | fatal ("could not initialise libev, bad $LIBEV_FLAGS in environment?"); |
547 | fatal ("could not initialise libev, bad $LIBEV_FLAGS in environment?"); |
… | |
… | |
573 | as signal and child watchers) would need to be stopped manually. |
590 | as signal and child watchers) would need to be stopped manually. |
574 | |
591 | |
575 | In general it is not advisable to call this function except in the |
592 | In general it is not advisable to call this function except in the |
576 | rare occasion where you really need to free e.g. the signal handling |
593 | rare occasion where you really need to free e.g. the signal handling |
577 | pipe fds. If you need dynamically allocated loops it is better to use |
594 | pipe fds. If you need dynamically allocated loops it is better to use |
578 | C<ev_loop_new> and C<ev_loop_destroy>). |
595 | C<ev_loop_new> and C<ev_loop_destroy>. |
579 | |
596 | |
580 | =item ev_loop_destroy (loop) |
597 | =item ev_loop_destroy (loop) |
581 | |
598 | |
582 | Like C<ev_default_destroy>, but destroys an event loop created by an |
599 | Like C<ev_default_destroy>, but destroys an event loop created by an |
583 | earlier call to C<ev_loop_new>. |
600 | earlier call to C<ev_loop_new>. |
… | |
… | |
687 | event loop time (see C<ev_now_update>). |
704 | event loop time (see C<ev_now_update>). |
688 | |
705 | |
689 | =item ev_loop (loop, int flags) |
706 | =item ev_loop (loop, int flags) |
690 | |
707 | |
691 | Finally, this is it, the event handler. This function usually is called |
708 | Finally, this is it, the event handler. This function usually is called |
692 | after you initialised all your watchers and you want to start handling |
709 | after you have initialised all your watchers and you want to start |
693 | events. |
710 | handling events. |
694 | |
711 | |
695 | If the flags argument is specified as C<0>, it will not return until |
712 | If the flags argument is specified as C<0>, it will not return until |
696 | either no event watchers are active anymore or C<ev_unloop> was called. |
713 | either no event watchers are active anymore or C<ev_unloop> was called. |
697 | |
714 | |
698 | Please note that an explicit C<ev_unloop> is usually better than |
715 | Please note that an explicit C<ev_unloop> is usually better than |
… | |
… | |
862 | |
879 | |
863 | This call will simply invoke all pending watchers while resetting their |
880 | This call will simply invoke all pending watchers while resetting their |
864 | pending state. Normally, C<ev_loop> does this automatically when required, |
881 | pending state. Normally, C<ev_loop> does this automatically when required, |
865 | but when overriding the invoke callback this call comes handy. |
882 | but when overriding the invoke callback this call comes handy. |
866 | |
883 | |
|
|
884 | =item int ev_pending_count (loop) |
|
|
885 | |
|
|
886 | Returns the number of pending watchers - zero indicates that no watchers |
|
|
887 | are pending. |
|
|
888 | |
867 | =item ev_set_invoke_pending_cb (loop, void (*invoke_pending_cb)(EV_P)) |
889 | =item ev_set_invoke_pending_cb (loop, void (*invoke_pending_cb)(EV_P)) |
868 | |
890 | |
869 | This overrides the invoke pending functionality of the loop: Instead of |
891 | This overrides the invoke pending functionality of the loop: Instead of |
870 | invoking all pending watchers when there are any, C<ev_loop> will call |
892 | invoking all pending watchers when there are any, C<ev_loop> will call |
871 | this callback instead. This is useful, for example, when you want to |
893 | this callback instead. This is useful, for example, when you want to |
… | |
… | |
1750 | |
1772 | |
1751 | If the event loop is suspended for a long time, you can also force an |
1773 | If the event loop is suspended for a long time, you can also force an |
1752 | update of the time returned by C<ev_now ()> by calling C<ev_now_update |
1774 | update of the time returned by C<ev_now ()> by calling C<ev_now_update |
1753 | ()>. |
1775 | ()>. |
1754 | |
1776 | |
|
|
1777 | =head3 The special problems of suspended animation |
|
|
1778 | |
|
|
1779 | When you leave the server world it is quite customary to hit machines that |
|
|
1780 | can suspend/hibernate - what happens to the clocks during such a suspend? |
|
|
1781 | |
|
|
1782 | Some quick tests made with a Linux 2.6.28 indicate that a suspend freezes |
|
|
1783 | all processes, while the clocks (C<times>, C<CLOCK_MONOTONIC>) continue |
|
|
1784 | to run until the system is suspended, but they will not advance while the |
|
|
1785 | system is suspended. That means, on resume, it will be as if the program |
|
|
1786 | was frozen for a few seconds, but the suspend time will not be counted |
|
|
1787 | towards C<ev_timer> when a monotonic clock source is used. The real time |
|
|
1788 | clock advanced as expected, but if it is used as sole clocksource, then a |
|
|
1789 | long suspend would be detected as a time jump by libev, and timers would |
|
|
1790 | be adjusted accordingly. |
|
|
1791 | |
|
|
1792 | I would not be surprised to see different behaviour in different between |
|
|
1793 | operating systems, OS versions or even different hardware. |
|
|
1794 | |
|
|
1795 | The other form of suspend (job control, or sending a SIGSTOP) will see a |
|
|
1796 | time jump in the monotonic clocks and the realtime clock. If the program |
|
|
1797 | is suspended for a very long time, and monotonic clock sources are in use, |
|
|
1798 | then you can expect C<ev_timer>s to expire as the full suspension time |
|
|
1799 | will be counted towards the timers. When no monotonic clock source is in |
|
|
1800 | use, then libev will again assume a timejump and adjust accordingly. |
|
|
1801 | |
|
|
1802 | It might be beneficial for this latter case to call C<ev_suspend> |
|
|
1803 | and C<ev_resume> in code that handles C<SIGTSTP>, to at least get |
|
|
1804 | deterministic behaviour in this case (you can do nothing against |
|
|
1805 | C<SIGSTOP>). |
|
|
1806 | |
1755 | =head3 Watcher-Specific Functions and Data Members |
1807 | =head3 Watcher-Specific Functions and Data Members |
1756 | |
1808 | |
1757 | =over 4 |
1809 | =over 4 |
1758 | |
1810 | |
1759 | =item ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat) |
1811 | =item ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat) |
… | |
… | |
1784 | If the timer is repeating, either start it if necessary (with the |
1836 | If the timer is repeating, either start it if necessary (with the |
1785 | C<repeat> value), or reset the running timer to the C<repeat> value. |
1837 | C<repeat> value), or reset the running timer to the C<repeat> value. |
1786 | |
1838 | |
1787 | This sounds a bit complicated, see L<Be smart about timeouts>, above, for a |
1839 | This sounds a bit complicated, see L<Be smart about timeouts>, above, for a |
1788 | usage example. |
1840 | usage example. |
|
|
1841 | |
|
|
1842 | =item ev_timer_remaining (loop, ev_timer *) |
|
|
1843 | |
|
|
1844 | Returns the remaining time until a timer fires. If the timer is active, |
|
|
1845 | then this time is relative to the current event loop time, otherwise it's |
|
|
1846 | the timeout value currently configured. |
|
|
1847 | |
|
|
1848 | That is, after an C<ev_timer_set (w, 5, 7)>, C<ev_timer_remaining> returns |
|
|
1849 | C<5>. When the timer is started and one second passes, C<ev_timer_remain> |
|
|
1850 | will return C<4>. When the timer expires and is restarted, it will return |
|
|
1851 | roughly C<7> (likely slightly less as callback invocation takes some time, |
|
|
1852 | too), and so on. |
1789 | |
1853 | |
1790 | =item ev_tstamp repeat [read-write] |
1854 | =item ev_tstamp repeat [read-write] |
1791 | |
1855 | |
1792 | The current C<repeat> value. Will be used each time the watcher times out |
1856 | The current C<repeat> value. Will be used each time the watcher times out |
1793 | or C<ev_timer_again> is called, and determines the next timeout (if any), |
1857 | or C<ev_timer_again> is called, and determines the next timeout (if any), |
… | |
… | |
2029 | Signal watchers will trigger an event when the process receives a specific |
2093 | Signal watchers will trigger an event when the process receives a specific |
2030 | signal one or more times. Even though signals are very asynchronous, libev |
2094 | signal one or more times. Even though signals are very asynchronous, libev |
2031 | will try it's best to deliver signals synchronously, i.e. as part of the |
2095 | will try it's best to deliver signals synchronously, i.e. as part of the |
2032 | normal event processing, like any other event. |
2096 | normal event processing, like any other event. |
2033 | |
2097 | |
2034 | If you want signals asynchronously, just use C<sigaction> as you would |
2098 | If you want signals to be delivered truly asynchronously, just use |
2035 | do without libev and forget about sharing the signal. You can even use |
2099 | C<sigaction> as you would do without libev and forget about sharing |
2036 | C<ev_async> from a signal handler to synchronously wake up an event loop. |
2100 | the signal. You can even use C<ev_async> from a signal handler to |
|
|
2101 | synchronously wake up an event loop. |
2037 | |
2102 | |
2038 | You can configure as many watchers as you like per signal. Only when the |
2103 | You can configure as many watchers as you like for the same signal, but |
|
|
2104 | only within the same loop, i.e. you can watch for C<SIGINT> in your |
|
|
2105 | default loop and for C<SIGIO> in another loop, but you cannot watch for |
|
|
2106 | C<SIGINT> in both the default loop and another loop at the same time. At |
|
|
2107 | the moment, C<SIGCHLD> is permanently tied to the default loop. |
|
|
2108 | |
2039 | first watcher gets started will libev actually register a signal handler |
2109 | When the first watcher gets started will libev actually register something |
2040 | with the kernel (thus it coexists with your own signal handlers as long as |
2110 | with the kernel (thus it coexists with your own signal handlers as long as |
2041 | you don't register any with libev for the same signal). Similarly, when |
2111 | you don't register any with libev for the same signal). |
2042 | the last signal watcher for a signal is stopped, libev will reset the |
|
|
2043 | signal handler to SIG_DFL (regardless of what it was set to before). |
|
|
2044 | |
2112 | |
2045 | If possible and supported, libev will install its handlers with |
2113 | If possible and supported, libev will install its handlers with |
2046 | C<SA_RESTART> behaviour enabled, so system calls should not be unduly |
2114 | C<SA_RESTART> (or equivalent) behaviour enabled, so system calls should |
2047 | interrupted. If you have a problem with system calls getting interrupted by |
2115 | not be unduly interrupted. If you have a problem with system calls getting |
2048 | signals you can block all signals in an C<ev_check> watcher and unblock |
2116 | interrupted by signals you can block all signals in an C<ev_check> watcher |
2049 | them in an C<ev_prepare> watcher. |
2117 | and unblock them in an C<ev_prepare> watcher. |
|
|
2118 | |
|
|
2119 | =head3 The special problem of inheritance over execve |
|
|
2120 | |
|
|
2121 | Both the signal mask (C<sigprocmask>) and the signal disposition |
|
|
2122 | (C<sigaction>) are unspecified after starting a signal watcher (and after |
|
|
2123 | stopping it again), that is, libev might or might not block the signal, |
|
|
2124 | and might or might not set or restore the installed signal handler. |
|
|
2125 | |
|
|
2126 | While this does not matter for the signal disposition (libev never |
|
|
2127 | sets signals to C<SIG_IGN>, so handlers will be reset to C<SIG_DFL> on |
|
|
2128 | C<execve>), this matters for the signal mask: many programs do not expect |
|
|
2129 | certain signals to be blocked. |
|
|
2130 | |
|
|
2131 | This means that before calling C<exec> (from the child) you should reset |
|
|
2132 | the signal mask to whatever "default" you expect (all clear is a good |
|
|
2133 | choice usually). |
|
|
2134 | |
|
|
2135 | The simplest way to ensure that the signal mask is reset in the child is |
|
|
2136 | to install a fork handler with C<pthread_atfork> that resets it. That will |
|
|
2137 | catch fork calls done by libraries (such as the libc) as well. |
|
|
2138 | |
|
|
2139 | In current versions of libev, you can also ensure that the signal mask is |
|
|
2140 | not blocking any signals (except temporarily, so thread users watch out) |
|
|
2141 | by specifying the C<EVFLAG_NOSIGNALFD> when creating the event loop. This |
|
|
2142 | is not guaranteed for future versions, however. |
2050 | |
2143 | |
2051 | =head3 Watcher-Specific Functions and Data Members |
2144 | =head3 Watcher-Specific Functions and Data Members |
2052 | |
2145 | |
2053 | =over 4 |
2146 | =over 4 |
2054 | |
2147 | |
… | |
… | |
2099 | libev) |
2192 | libev) |
2100 | |
2193 | |
2101 | =head3 Process Interaction |
2194 | =head3 Process Interaction |
2102 | |
2195 | |
2103 | Libev grabs C<SIGCHLD> as soon as the default event loop is |
2196 | Libev grabs C<SIGCHLD> as soon as the default event loop is |
2104 | initialised. This is necessary to guarantee proper behaviour even if |
2197 | initialised. This is necessary to guarantee proper behaviour even if the |
2105 | the first child watcher is started after the child exits. The occurrence |
2198 | first child watcher is started after the child exits. The occurrence |
2106 | of C<SIGCHLD> is recorded asynchronously, but child reaping is done |
2199 | of C<SIGCHLD> is recorded asynchronously, but child reaping is done |
2107 | synchronously as part of the event loop processing. Libev always reaps all |
2200 | synchronously as part of the event loop processing. Libev always reaps all |
2108 | children, even ones not watched. |
2201 | children, even ones not watched. |
2109 | |
2202 | |
2110 | =head3 Overriding the Built-In Processing |
2203 | =head3 Overriding the Built-In Processing |
… | |
… | |
2120 | =head3 Stopping the Child Watcher |
2213 | =head3 Stopping the Child Watcher |
2121 | |
2214 | |
2122 | Currently, the child watcher never gets stopped, even when the |
2215 | Currently, the child watcher never gets stopped, even when the |
2123 | child terminates, so normally one needs to stop the watcher in the |
2216 | child terminates, so normally one needs to stop the watcher in the |
2124 | callback. Future versions of libev might stop the watcher automatically |
2217 | callback. Future versions of libev might stop the watcher automatically |
2125 | when a child exit is detected. |
2218 | when a child exit is detected (calling C<ev_child_stop> twice is not a |
|
|
2219 | problem). |
2126 | |
2220 | |
2127 | =head3 Watcher-Specific Functions and Data Members |
2221 | =head3 Watcher-Specific Functions and Data Members |
2128 | |
2222 | |
2129 | =over 4 |
2223 | =over 4 |
2130 | |
2224 | |
… | |
… | |
3333 | =item Ocaml |
3427 | =item Ocaml |
3334 | |
3428 | |
3335 | Erkki Seppala has written Ocaml bindings for libev, to be found at |
3429 | Erkki Seppala has written Ocaml bindings for libev, to be found at |
3336 | L<http://modeemi.cs.tut.fi/~flux/software/ocaml-ev/>. |
3430 | L<http://modeemi.cs.tut.fi/~flux/software/ocaml-ev/>. |
3337 | |
3431 | |
|
|
3432 | =item Lua |
|
|
3433 | |
|
|
3434 | Brian Maher has written a partial interface to libev |
|
|
3435 | for lua (only C<ev_io> and C<ev_timer>), to be found at |
|
|
3436 | L<http://github.com/brimworks/lua-ev>. |
|
|
3437 | |
3338 | =back |
3438 | =back |
3339 | |
3439 | |
3340 | |
3440 | |
3341 | =head1 MACRO MAGIC |
3441 | =head1 MACRO MAGIC |
3342 | |
3442 | |
… | |
… | |
3508 | keeps libev from including F<config.h>, and it also defines dummy |
3608 | keeps libev from including F<config.h>, and it also defines dummy |
3509 | implementations for some libevent functions (such as logging, which is not |
3609 | implementations for some libevent functions (such as logging, which is not |
3510 | supported). It will also not define any of the structs usually found in |
3610 | supported). It will also not define any of the structs usually found in |
3511 | F<event.h> that are not directly supported by the libev core alone. |
3611 | F<event.h> that are not directly supported by the libev core alone. |
3512 | |
3612 | |
3513 | In stanbdalone mode, libev will still try to automatically deduce the |
3613 | In standalone mode, libev will still try to automatically deduce the |
3514 | configuration, but has to be more conservative. |
3614 | configuration, but has to be more conservative. |
3515 | |
3615 | |
3516 | =item EV_USE_MONOTONIC |
3616 | =item EV_USE_MONOTONIC |
3517 | |
3617 | |
3518 | If defined to be C<1>, libev will try to detect the availability of the |
3618 | If defined to be C<1>, libev will try to detect the availability of the |
… | |
… | |
3583 | be used is the winsock select). This means that it will call |
3683 | be used is the winsock select). This means that it will call |
3584 | C<_get_osfhandle> on the fd to convert it to an OS handle. Otherwise, |
3684 | C<_get_osfhandle> on the fd to convert it to an OS handle. Otherwise, |
3585 | it is assumed that all these functions actually work on fds, even |
3685 | it is assumed that all these functions actually work on fds, even |
3586 | on win32. Should not be defined on non-win32 platforms. |
3686 | on win32. Should not be defined on non-win32 platforms. |
3587 | |
3687 | |
3588 | =item EV_FD_TO_WIN32_HANDLE |
3688 | =item EV_FD_TO_WIN32_HANDLE(fd) |
3589 | |
3689 | |
3590 | If C<EV_SELECT_IS_WINSOCKET> is enabled, then libev needs a way to map |
3690 | If C<EV_SELECT_IS_WINSOCKET> is enabled, then libev needs a way to map |
3591 | file descriptors to socket handles. When not defining this symbol (the |
3691 | file descriptors to socket handles. When not defining this symbol (the |
3592 | default), then libev will call C<_get_osfhandle>, which is usually |
3692 | default), then libev will call C<_get_osfhandle>, which is usually |
3593 | correct. In some cases, programs use their own file descriptor management, |
3693 | correct. In some cases, programs use their own file descriptor management, |
3594 | in which case they can provide this function to map fds to socket handles. |
3694 | in which case they can provide this function to map fds to socket handles. |
|
|
3695 | |
|
|
3696 | =item EV_WIN32_HANDLE_TO_FD(handle) |
|
|
3697 | |
|
|
3698 | If C<EV_SELECT_IS_WINSOCKET> then libev maps handles to file descriptors |
|
|
3699 | using the standard C<_open_osfhandle> function. For programs implementing |
|
|
3700 | their own fd to handle mapping, overwriting this function makes it easier |
|
|
3701 | to do so. This can be done by defining this macro to an appropriate value. |
|
|
3702 | |
|
|
3703 | =item EV_WIN32_CLOSE_FD(fd) |
|
|
3704 | |
|
|
3705 | If programs implement their own fd to handle mapping on win32, then this |
|
|
3706 | macro can be used to override the C<close> function, useful to unregister |
|
|
3707 | file descriptors again. Note that the replacement function has to close |
|
|
3708 | the underlying OS handle. |
3595 | |
3709 | |
3596 | =item EV_USE_POLL |
3710 | =item EV_USE_POLL |
3597 | |
3711 | |
3598 | If defined to be C<1>, libev will compile in support for the C<poll>(2) |
3712 | If defined to be C<1>, libev will compile in support for the C<poll>(2) |
3599 | backend. Otherwise it will be enabled on non-win32 platforms. It |
3713 | backend. Otherwise it will be enabled on non-win32 platforms. It |
… | |
… | |
3745 | Defining C<EV_MINIMAL> to C<2> will additionally reduce the core API to |
3859 | Defining C<EV_MINIMAL> to C<2> will additionally reduce the core API to |
3746 | provide a bare-bones event library. See C<ev.h> for details on what parts |
3860 | provide a bare-bones event library. See C<ev.h> for details on what parts |
3747 | of the API are still available, and do not complain if this subset changes |
3861 | of the API are still available, and do not complain if this subset changes |
3748 | over time. |
3862 | over time. |
3749 | |
3863 | |
|
|
3864 | =item EV_NSIG |
|
|
3865 | |
|
|
3866 | The highest supported signal number, +1 (or, the number of |
|
|
3867 | signals): Normally, libev tries to deduce the maximum number of signals |
|
|
3868 | automatically, but sometimes this fails, in which case it can be |
|
|
3869 | specified. Also, using a lower number than detected (C<32> should be |
|
|
3870 | good for about any system in existance) can save some memory, as libev |
|
|
3871 | statically allocates some 12-24 bytes per signal number. |
|
|
3872 | |
3750 | =item EV_PID_HASHSIZE |
3873 | =item EV_PID_HASHSIZE |
3751 | |
3874 | |
3752 | C<ev_child> watchers use a small hash table to distribute workload by |
3875 | C<ev_child> watchers use a small hash table to distribute workload by |
3753 | pid. The default size is C<16> (or C<1> with C<EV_MINIMAL>), usually more |
3876 | pid. The default size is C<16> (or C<1> with C<EV_MINIMAL>), usually more |
3754 | than enough. If you need to manage thousands of children you might want to |
3877 | than enough. If you need to manage thousands of children you might want to |
… | |
… | |
4028 | } |
4151 | } |
4029 | |
4152 | |
4030 | Instead of invoking all pending watchers, the C<l_invoke> callback will |
4153 | Instead of invoking all pending watchers, the C<l_invoke> callback will |
4031 | signal the main thread via some unspecified mechanism (signals? pipe |
4154 | signal the main thread via some unspecified mechanism (signals? pipe |
4032 | writes? C<Async::Interrupt>?) and then waits until all pending watchers |
4155 | writes? C<Async::Interrupt>?) and then waits until all pending watchers |
4033 | have been called: |
4156 | have been called (in a while loop because a) spurious wakeups are possible |
|
|
4157 | and b) skipping inter-thread-communication when there are no pending |
|
|
4158 | watchers is very beneficial): |
4034 | |
4159 | |
4035 | static void |
4160 | static void |
4036 | l_invoke (EV_P) |
4161 | l_invoke (EV_P) |
4037 | { |
4162 | { |
4038 | userdata *u = ev_userdata (EV_A); |
4163 | userdata *u = ev_userdata (EV_A); |
4039 | |
4164 | |
|
|
4165 | while (ev_pending_count (EV_A)) |
|
|
4166 | { |
4040 | wake_up_other_thread_in_some_magic_or_not_so_magic_way (); |
4167 | wake_up_other_thread_in_some_magic_or_not_so_magic_way (); |
4041 | |
|
|
4042 | pthread_cond_wait (&u->invoke_cv, &u->lock); |
4168 | pthread_cond_wait (&u->invoke_cv, &u->lock); |
|
|
4169 | } |
4043 | } |
4170 | } |
4044 | |
4171 | |
4045 | Now, whenever the main thread gets told to invoke pending watchers, it |
4172 | Now, whenever the main thread gets told to invoke pending watchers, it |
4046 | will grab the lock, call C<ev_invoke_pending> and then signal the loop |
4173 | will grab the lock, call C<ev_invoke_pending> and then signal the loop |
4047 | thread to continue: |
4174 | thread to continue: |