… | |
… | |
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 | |
… | |
… | |
369 | When this flag is specified, then libev will not attempt to use the |
370 | When this flag is specified, then libev will not attempt to use the |
370 | I<inotify> API for it's C<ev_stat> watchers. Apart from debugging and |
371 | I<inotify> API for it's C<ev_stat> watchers. Apart from debugging and |
371 | testing, this flag can be useful to conserve inotify file descriptors, as |
372 | testing, this flag can be useful to conserve inotify file descriptors, as |
372 | otherwise each loop using C<ev_stat> watchers consumes one inotify handle. |
373 | otherwise each loop using C<ev_stat> watchers consumes one inotify handle. |
373 | |
374 | |
374 | =item C<EVFLAG_NOSIGNALFD> |
375 | =item C<EVFLAG_NOSIGFD> |
375 | |
376 | |
376 | When this flag is specified, then libev will not attempt to use the |
377 | When this flag is specified, then libev will not attempt to use the |
377 | I<signalfd> API for it's C<ev_signal> (and C<ev_child>) watchers. This is |
378 | I<signalfd> API for it's C<ev_signal> (and C<ev_child>) watchers. This is |
378 | probably only useful to work around any bugs in libev. Consequently, this |
379 | probably only useful to work around any bugs in libev. Consequently, this |
379 | flag might go away once the signalfd functionality is considered stable, |
380 | flag might go away once the signalfd functionality is considered stable, |
… | |
… | |
409 | |
410 | |
410 | This backend maps C<EV_READ> to C<POLLIN | POLLERR | POLLHUP>, and |
411 | This backend maps C<EV_READ> to C<POLLIN | POLLERR | POLLHUP>, and |
411 | C<EV_WRITE> to C<POLLOUT | POLLERR | POLLHUP>. |
412 | C<EV_WRITE> to C<POLLOUT | POLLERR | POLLHUP>. |
412 | |
413 | |
413 | =item C<EVBACKEND_EPOLL> (value 4, Linux) |
414 | =item C<EVBACKEND_EPOLL> (value 4, Linux) |
|
|
415 | |
|
|
416 | Use the linux-specific epoll(7) interface (for both pre- and post-2.6.9 |
|
|
417 | kernels). |
414 | |
418 | |
415 | For few fds, this backend is a bit little slower than poll and select, |
419 | For few fds, this backend is a bit little slower than poll and select, |
416 | but it scales phenomenally better. While poll and select usually scale |
420 | but it scales phenomenally better. While poll and select usually scale |
417 | like O(total_fds) where n is the total number of fds (or the highest fd), |
421 | like O(total_fds) where n is the total number of fds (or the highest fd), |
418 | epoll scales either O(1) or O(active_fds). |
422 | epoll scales either O(1) or O(active_fds). |
… | |
… | |
589 | as signal and child watchers) would need to be stopped manually. |
593 | as signal and child watchers) would need to be stopped manually. |
590 | |
594 | |
591 | In general it is not advisable to call this function except in the |
595 | In general it is not advisable to call this function except in the |
592 | rare occasion where you really need to free e.g. the signal handling |
596 | rare occasion where you really need to free e.g. the signal handling |
593 | pipe fds. If you need dynamically allocated loops it is better to use |
597 | pipe fds. If you need dynamically allocated loops it is better to use |
594 | C<ev_loop_new> and C<ev_loop_destroy>). |
598 | C<ev_loop_new> and C<ev_loop_destroy>. |
595 | |
599 | |
596 | =item ev_loop_destroy (loop) |
600 | =item ev_loop_destroy (loop) |
597 | |
601 | |
598 | Like C<ev_default_destroy>, but destroys an event loop created by an |
602 | Like C<ev_default_destroy>, but destroys an event loop created by an |
599 | earlier call to C<ev_loop_new>. |
603 | earlier call to C<ev_loop_new>. |
… | |
… | |
703 | event loop time (see C<ev_now_update>). |
707 | event loop time (see C<ev_now_update>). |
704 | |
708 | |
705 | =item ev_loop (loop, int flags) |
709 | =item ev_loop (loop, int flags) |
706 | |
710 | |
707 | Finally, this is it, the event handler. This function usually is called |
711 | Finally, this is it, the event handler. This function usually is called |
708 | after you initialised all your watchers and you want to start handling |
712 | after you have initialised all your watchers and you want to start |
709 | events. |
713 | handling events. |
710 | |
714 | |
711 | If the flags argument is specified as C<0>, it will not return until |
715 | If the flags argument is specified as C<0>, it will not return until |
712 | either no event watchers are active anymore or C<ev_unloop> was called. |
716 | either no event watchers are active anymore or C<ev_unloop> was called. |
713 | |
717 | |
714 | Please note that an explicit C<ev_unloop> is usually better than |
718 | Please note that an explicit C<ev_unloop> is usually better than |
… | |
… | |
1232 | watcher isn't pending it does nothing and returns C<0>. |
1236 | watcher isn't pending it does nothing and returns C<0>. |
1233 | |
1237 | |
1234 | Sometimes it can be useful to "poll" a watcher instead of waiting for its |
1238 | Sometimes it can be useful to "poll" a watcher instead of waiting for its |
1235 | callback to be invoked, which can be accomplished with this function. |
1239 | callback to be invoked, which can be accomplished with this function. |
1236 | |
1240 | |
|
|
1241 | =item ev_feed_event (struct ev_loop *, watcher *, int revents) |
|
|
1242 | |
|
|
1243 | Feeds the given event set into the event loop, as if the specified event |
|
|
1244 | had happened for the specified watcher (which must be a pointer to an |
|
|
1245 | initialised but not necessarily started event watcher). Obviously you must |
|
|
1246 | not free the watcher as long as it has pending events. |
|
|
1247 | |
|
|
1248 | Stopping the watcher, letting libev invoke it, or calling |
|
|
1249 | C<ev_clear_pending> will clear the pending event, even if the watcher was |
|
|
1250 | not started in the first place. |
|
|
1251 | |
|
|
1252 | See also C<ev_feed_fd_event> and C<ev_feed_signal_event> for related |
|
|
1253 | functions that do not need a watcher. |
|
|
1254 | |
1237 | =back |
1255 | =back |
1238 | |
1256 | |
1239 | |
1257 | |
1240 | =head2 ASSOCIATING CUSTOM DATA WITH A WATCHER |
1258 | =head2 ASSOCIATING CUSTOM DATA WITH A WATCHER |
1241 | |
1259 | |
… | |
… | |
2107 | |
2125 | |
2108 | When the first watcher gets started will libev actually register something |
2126 | When the first watcher gets started will libev actually register something |
2109 | with the kernel (thus it coexists with your own signal handlers as long as |
2127 | with the kernel (thus it coexists with your own signal handlers as long as |
2110 | you don't register any with libev for the same signal). |
2128 | you don't register any with libev for the same signal). |
2111 | |
2129 | |
2112 | Both the signal mask state (C<sigprocmask>) and the signal handler state |
|
|
2113 | (C<sigaction>) are unspecified after starting a signal watcher (and after |
|
|
2114 | sotpping it again), that is, libev might or might not block the signal, |
|
|
2115 | and might or might not set or restore the installed signal handler. |
|
|
2116 | |
|
|
2117 | If possible and supported, libev will install its handlers with |
2130 | If possible and supported, libev will install its handlers with |
2118 | C<SA_RESTART> (or equivalent) behaviour enabled, so system calls should |
2131 | C<SA_RESTART> (or equivalent) behaviour enabled, so system calls should |
2119 | not be unduly interrupted. If you have a problem with system calls getting |
2132 | not be unduly interrupted. If you have a problem with system calls getting |
2120 | interrupted by signals you can block all signals in an C<ev_check> watcher |
2133 | interrupted by signals you can block all signals in an C<ev_check> watcher |
2121 | and unblock them in an C<ev_prepare> watcher. |
2134 | and unblock them in an C<ev_prepare> watcher. |
|
|
2135 | |
|
|
2136 | =head3 The special problem of inheritance over execve |
|
|
2137 | |
|
|
2138 | Both the signal mask (C<sigprocmask>) and the signal disposition |
|
|
2139 | (C<sigaction>) are unspecified after starting a signal watcher (and after |
|
|
2140 | stopping it again), that is, libev might or might not block the signal, |
|
|
2141 | and might or might not set or restore the installed signal handler. |
|
|
2142 | |
|
|
2143 | While this does not matter for the signal disposition (libev never |
|
|
2144 | sets signals to C<SIG_IGN>, so handlers will be reset to C<SIG_DFL> on |
|
|
2145 | C<execve>), this matters for the signal mask: many programs do not expect |
|
|
2146 | certain signals to be blocked. |
|
|
2147 | |
|
|
2148 | This means that before calling C<exec> (from the child) you should reset |
|
|
2149 | the signal mask to whatever "default" you expect (all clear is a good |
|
|
2150 | choice usually). |
|
|
2151 | |
|
|
2152 | The simplest way to ensure that the signal mask is reset in the child is |
|
|
2153 | to install a fork handler with C<pthread_atfork> that resets it. That will |
|
|
2154 | catch fork calls done by libraries (such as the libc) as well. |
|
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2155 | |
|
|
2156 | In current versions of libev, you can also ensure that the signal mask is |
|
|
2157 | not blocking any signals (except temporarily, so thread users watch out) |
|
|
2158 | by specifying the C<EVFLAG_NOSIGFD> when creating the event loop. This |
|
|
2159 | is not guaranteed for future versions, however. |
2122 | |
2160 | |
2123 | =head3 Watcher-Specific Functions and Data Members |
2161 | =head3 Watcher-Specific Functions and Data Members |
2124 | |
2162 | |
2125 | =over 4 |
2163 | =over 4 |
2126 | |
2164 | |
… | |
… | |
3111 | /* doh, nothing entered */; |
3149 | /* doh, nothing entered */; |
3112 | } |
3150 | } |
3113 | |
3151 | |
3114 | ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0); |
3152 | ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0); |
3115 | |
3153 | |
3116 | =item ev_feed_event (struct ev_loop *, watcher *, int revents) |
|
|
3117 | |
|
|
3118 | Feeds the given event set into the event loop, as if the specified event |
|
|
3119 | had happened for the specified watcher (which must be a pointer to an |
|
|
3120 | initialised but not necessarily started event watcher). |
|
|
3121 | |
|
|
3122 | =item ev_feed_fd_event (struct ev_loop *, int fd, int revents) |
3154 | =item ev_feed_fd_event (struct ev_loop *, int fd, int revents) |
3123 | |
3155 | |
3124 | Feed an event on the given fd, as if a file descriptor backend detected |
3156 | Feed an event on the given fd, as if a file descriptor backend detected |
3125 | the given events it. |
3157 | the given events it. |
3126 | |
3158 | |
… | |
… | |
3406 | =item Ocaml |
3438 | =item Ocaml |
3407 | |
3439 | |
3408 | Erkki Seppala has written Ocaml bindings for libev, to be found at |
3440 | Erkki Seppala has written Ocaml bindings for libev, to be found at |
3409 | L<http://modeemi.cs.tut.fi/~flux/software/ocaml-ev/>. |
3441 | L<http://modeemi.cs.tut.fi/~flux/software/ocaml-ev/>. |
3410 | |
3442 | |
|
|
3443 | =item Lua |
|
|
3444 | |
|
|
3445 | Brian Maher has written a partial interface to libev |
|
|
3446 | for lua (only C<ev_io> and C<ev_timer>), to be found at |
|
|
3447 | L<http://github.com/brimworks/lua-ev>. |
|
|
3448 | |
3411 | =back |
3449 | =back |
3412 | |
3450 | |
3413 | |
3451 | |
3414 | =head1 MACRO MAGIC |
3452 | =head1 MACRO MAGIC |
3415 | |
3453 | |
… | |
… | |
3581 | keeps libev from including F<config.h>, and it also defines dummy |
3619 | keeps libev from including F<config.h>, and it also defines dummy |
3582 | implementations for some libevent functions (such as logging, which is not |
3620 | implementations for some libevent functions (such as logging, which is not |
3583 | supported). It will also not define any of the structs usually found in |
3621 | supported). It will also not define any of the structs usually found in |
3584 | F<event.h> that are not directly supported by the libev core alone. |
3622 | F<event.h> that are not directly supported by the libev core alone. |
3585 | |
3623 | |
3586 | In stanbdalone mode, libev will still try to automatically deduce the |
3624 | In standalone mode, libev will still try to automatically deduce the |
3587 | configuration, but has to be more conservative. |
3625 | configuration, but has to be more conservative. |
3588 | |
3626 | |
3589 | =item EV_USE_MONOTONIC |
3627 | =item EV_USE_MONOTONIC |
3590 | |
3628 | |
3591 | If defined to be C<1>, libev will try to detect the availability of the |
3629 | If defined to be C<1>, libev will try to detect the availability of the |
… | |
… | |
3656 | be used is the winsock select). This means that it will call |
3694 | be used is the winsock select). This means that it will call |
3657 | C<_get_osfhandle> on the fd to convert it to an OS handle. Otherwise, |
3695 | C<_get_osfhandle> on the fd to convert it to an OS handle. Otherwise, |
3658 | it is assumed that all these functions actually work on fds, even |
3696 | it is assumed that all these functions actually work on fds, even |
3659 | on win32. Should not be defined on non-win32 platforms. |
3697 | on win32. Should not be defined on non-win32 platforms. |
3660 | |
3698 | |
3661 | =item EV_FD_TO_WIN32_HANDLE |
3699 | =item EV_FD_TO_WIN32_HANDLE(fd) |
3662 | |
3700 | |
3663 | If C<EV_SELECT_IS_WINSOCKET> is enabled, then libev needs a way to map |
3701 | If C<EV_SELECT_IS_WINSOCKET> is enabled, then libev needs a way to map |
3664 | file descriptors to socket handles. When not defining this symbol (the |
3702 | file descriptors to socket handles. When not defining this symbol (the |
3665 | default), then libev will call C<_get_osfhandle>, which is usually |
3703 | default), then libev will call C<_get_osfhandle>, which is usually |
3666 | correct. In some cases, programs use their own file descriptor management, |
3704 | correct. In some cases, programs use their own file descriptor management, |
3667 | in which case they can provide this function to map fds to socket handles. |
3705 | in which case they can provide this function to map fds to socket handles. |
|
|
3706 | |
|
|
3707 | =item EV_WIN32_HANDLE_TO_FD(handle) |
|
|
3708 | |
|
|
3709 | If C<EV_SELECT_IS_WINSOCKET> then libev maps handles to file descriptors |
|
|
3710 | using the standard C<_open_osfhandle> function. For programs implementing |
|
|
3711 | their own fd to handle mapping, overwriting this function makes it easier |
|
|
3712 | to do so. This can be done by defining this macro to an appropriate value. |
|
|
3713 | |
|
|
3714 | =item EV_WIN32_CLOSE_FD(fd) |
|
|
3715 | |
|
|
3716 | If programs implement their own fd to handle mapping on win32, then this |
|
|
3717 | macro can be used to override the C<close> function, useful to unregister |
|
|
3718 | file descriptors again. Note that the replacement function has to close |
|
|
3719 | the underlying OS handle. |
3668 | |
3720 | |
3669 | =item EV_USE_POLL |
3721 | =item EV_USE_POLL |
3670 | |
3722 | |
3671 | If defined to be C<1>, libev will compile in support for the C<poll>(2) |
3723 | If defined to be C<1>, libev will compile in support for the C<poll>(2) |
3672 | backend. Otherwise it will be enabled on non-win32 platforms. It |
3724 | backend. Otherwise it will be enabled on non-win32 platforms. It |