… | |
… | |
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, |
… | |
… | |
589 | as signal and child watchers) would need to be stopped manually. |
590 | as signal and child watchers) would need to be stopped manually. |
590 | |
591 | |
591 | 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 |
592 | 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 |
593 | 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 |
594 | C<ev_loop_new> and C<ev_loop_destroy>). |
595 | C<ev_loop_new> and C<ev_loop_destroy>. |
595 | |
596 | |
596 | =item ev_loop_destroy (loop) |
597 | =item ev_loop_destroy (loop) |
597 | |
598 | |
598 | 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 |
599 | earlier call to C<ev_loop_new>. |
600 | earlier call to C<ev_loop_new>. |
… | |
… | |
703 | event loop time (see C<ev_now_update>). |
704 | event loop time (see C<ev_now_update>). |
704 | |
705 | |
705 | =item ev_loop (loop, int flags) |
706 | =item ev_loop (loop, int flags) |
706 | |
707 | |
707 | 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 |
708 | 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 |
709 | events. |
710 | handling events. |
710 | |
711 | |
711 | 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 |
712 | 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. |
713 | |
714 | |
714 | 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 |
… | |
… | |
2107 | |
2108 | |
2108 | When the first watcher gets started will libev actually register something |
2109 | 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 |
2110 | 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). |
2111 | you don't register any with libev for the same signal). |
2111 | |
2112 | |
2112 | Both the signal mask state (C<sigprocmask>) and the signal handler state |
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|
2113 | (C<sigaction>) are unspecified after starting a signal watcher (and after |
|
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2114 | sotpping it again), that is, libev might or might not block the signal, |
|
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2115 | and might or might not set or restore the installed signal handler. |
|
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2116 | |
|
|
2117 | If possible and supported, libev will install its handlers with |
2113 | If possible and supported, libev will install its handlers with |
2118 | C<SA_RESTART> (or equivalent) behaviour enabled, so system calls should |
2114 | 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 |
2115 | 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 |
2116 | interrupted by signals you can block all signals in an C<ev_check> watcher |
2121 | and unblock them in an C<ev_prepare> watcher. |
2117 | and unblock them in an C<ev_prepare> watcher. |
|
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2118 | |
|
|
2119 | =head3 The special problem of inheritance over execve |
|
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2120 | |
|
|
2121 | Both the signal mask (C<sigprocmask>) and the signal disposition |
|
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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, |
|
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2124 | and might or might not set or restore the installed signal handler. |
|
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2125 | |
|
|
2126 | While this does not matter for the signal disposition (libev never |
|
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2127 | sets signals to C<SIG_IGN>, so handlers will be reset to C<SIG_DFL> on |
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2128 | C<execve>), this matters for the signal mask: many programs do not expect |
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2129 | certain signals to be blocked. |
|
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2130 | |
|
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2131 | This means that before calling C<exec> (from the child) you should reset |
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2132 | the signal mask to whatever "default" you expect (all clear is a good |
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2133 | choice usually). |
|
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2134 | |
|
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2135 | The simplest way to ensure that the signal mask is reset in the child is |
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2136 | to install a fork handler with C<pthread_atfork> that resets it. That will |
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2137 | catch fork calls done by libraries (such as the libc) as well. |
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2138 | |
|
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2139 | In current versions of libev, you can also ensure that the signal mask is |
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2140 | not blocking any signals (except temporarily, so thread users watch out) |
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2141 | by specifying the C<EVFLAG_NOSIGFD> when creating the event loop. This |
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2142 | is not guaranteed for future versions, however. |
2122 | |
2143 | |
2123 | =head3 Watcher-Specific Functions and Data Members |
2144 | =head3 Watcher-Specific Functions and Data Members |
2124 | |
2145 | |
2125 | =over 4 |
2146 | =over 4 |
2126 | |
2147 | |
… | |
… | |
3406 | =item Ocaml |
3427 | =item Ocaml |
3407 | |
3428 | |
3408 | 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 |
3409 | L<http://modeemi.cs.tut.fi/~flux/software/ocaml-ev/>. |
3430 | L<http://modeemi.cs.tut.fi/~flux/software/ocaml-ev/>. |
3410 | |
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 | |
3411 | =back |
3438 | =back |
3412 | |
3439 | |
3413 | |
3440 | |
3414 | =head1 MACRO MAGIC |
3441 | =head1 MACRO MAGIC |
3415 | |
3442 | |
… | |
… | |
3581 | 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 |
3582 | implementations for some libevent functions (such as logging, which is not |
3609 | 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 |
3610 | 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. |
3611 | F<event.h> that are not directly supported by the libev core alone. |
3585 | |
3612 | |
3586 | In stanbdalone mode, libev will still try to automatically deduce the |
3613 | In standalone mode, libev will still try to automatically deduce the |
3587 | configuration, but has to be more conservative. |
3614 | configuration, but has to be more conservative. |
3588 | |
3615 | |
3589 | =item EV_USE_MONOTONIC |
3616 | =item EV_USE_MONOTONIC |
3590 | |
3617 | |
3591 | 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 |
… | |
… | |
3656 | 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 |
3657 | 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, |
3658 | 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 |
3659 | on win32. Should not be defined on non-win32 platforms. |
3686 | on win32. Should not be defined on non-win32 platforms. |
3660 | |
3687 | |
3661 | =item EV_FD_TO_WIN32_HANDLE |
3688 | =item EV_FD_TO_WIN32_HANDLE(fd) |
3662 | |
3689 | |
3663 | 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 |
3664 | file descriptors to socket handles. When not defining this symbol (the |
3691 | file descriptors to socket handles. When not defining this symbol (the |
3665 | default), then libev will call C<_get_osfhandle>, which is usually |
3692 | default), then libev will call C<_get_osfhandle>, which is usually |
3666 | correct. In some cases, programs use their own file descriptor management, |
3693 | 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. |
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. |
3668 | |
3709 | |
3669 | =item EV_USE_POLL |
3710 | =item EV_USE_POLL |
3670 | |
3711 | |
3671 | 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) |
3672 | backend. Otherwise it will be enabled on non-win32 platforms. It |
3713 | backend. Otherwise it will be enabled on non-win32 platforms. It |