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Revision 1.260 by root, Sun Jul 19 21:18:03 2009 UTC vs.
Revision 1.265 by root, Wed Aug 26 17:11:42 2009 UTC

98=head2 FEATURES 98=head2 FEATURES
99 99
100Libev supports C<select>, C<poll>, the Linux-specific C<epoll>, the 100Libev supports C<select>, C<poll>, the Linux-specific C<epoll>, the
101BSD-specific C<kqueue> and the Solaris-specific event port mechanisms 101BSD-specific C<kqueue> and the Solaris-specific event port mechanisms
102for file descriptor events (C<ev_io>), the Linux C<inotify> interface 102for 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
104with customised rescheduling (C<ev_periodic>), synchronous signals 104inter-thread wakeup (C<ev_async>)/signal handling (C<ev_signal>)) relative
105(C<ev_signal>), process status change events (C<ev_child>), and event 105timers (C<ev_timer>), absolute timers with customised rescheduling
106watchers dealing with the event loop mechanism itself (C<ev_idle>, 106(C<ev_periodic>), synchronous signals (C<ev_signal>), process status
107C<ev_embed>, C<ev_prepare> and C<ev_check> watchers) as well as 107change events (C<ev_child>), and event watchers dealing with the event
108file watchers (C<ev_stat>) and even limited support for fork events 108loop mechanism itself (C<ev_idle>, C<ev_embed>, C<ev_prepare> and
109(C<ev_fork>). 109C<ev_check> watchers) as well as file watchers (C<ev_stat>) and even
110limited support for fork events (C<ev_fork>).
110 111
111It also is quite fast (see this 112It also is quite fast (see this
112L<benchmark|http://libev.schmorp.de/bench.html> comparing it to libevent 113L<benchmark|http://libev.schmorp.de/bench.html> comparing it to libevent
113for example). 114for example).
114 115
2107 2108
2108When the first watcher gets started will libev actually register something 2109When the first watcher gets started will libev actually register something
2109with the kernel (thus it coexists with your own signal handlers as long as 2110with the kernel (thus it coexists with your own signal handlers as long as
2110you don't register any with libev for the same signal). 2111you don't register any with libev for the same signal).
2111 2112
2112Both the signal mask state (C<sigprocmask>) and the signal handler state
2113(C<sigaction>) are unspecified after starting a signal watcher (and after
2114sotpping it again), that is, libev might or might not block the signal,
2115and might or might not set or restore the installed signal handler.
2116
2117If possible and supported, libev will install its handlers with 2113If possible and supported, libev will install its handlers with
2118C<SA_RESTART> (or equivalent) behaviour enabled, so system calls should 2114C<SA_RESTART> (or equivalent) behaviour enabled, so system calls should
2119not be unduly interrupted. If you have a problem with system calls getting 2115not be unduly interrupted. If you have a problem with system calls getting
2120interrupted by signals you can block all signals in an C<ev_check> watcher 2116interrupted by signals you can block all signals in an C<ev_check> watcher
2121and unblock them in an C<ev_prepare> watcher. 2117and unblock them in an C<ev_prepare> watcher.
2118
2119=head3 The special problem of inheritance over execve
2120
2121Both the signal mask (C<sigprocmask>) and the signal disposition
2122(C<sigaction>) are unspecified after starting a signal watcher (and after
2123stopping it again), that is, libev might or might not block the signal,
2124and might or might not set or restore the installed signal handler.
2125
2126While this does not matter for the signal disposition (libev never
2127sets signals to C<SIG_IGN>, so handlers will be reset to C<SIG_DFL> on
2128C<execve>), this matters for the signal mask: many programs do not expect
2129many signals to be blocked.
2130
2131This means that before calling C<exec> (from the child) you should reset
2132the signal mask to whatever "default" you expect (all clear is a good
2133choice usually).
2122 2134
2123=head3 Watcher-Specific Functions and Data Members 2135=head3 Watcher-Specific Functions and Data Members
2124 2136
2125=over 4 2137=over 4
2126 2138
3406=item Ocaml 3418=item Ocaml
3407 3419
3408Erkki Seppala has written Ocaml bindings for libev, to be found at 3420Erkki Seppala has written Ocaml bindings for libev, to be found at
3409L<http://modeemi.cs.tut.fi/~flux/software/ocaml-ev/>. 3421L<http://modeemi.cs.tut.fi/~flux/software/ocaml-ev/>.
3410 3422
3423=item Lua
3424
3425Brian Maher has written a partial interface to libev
3426for lua (only C<ev_io> and C<ev_timer>), to be found at
3427L<http://github.com/brimworks/lua-ev>.
3428
3411=back 3429=back
3412 3430
3413 3431
3414=head1 MACRO MAGIC 3432=head1 MACRO MAGIC
3415 3433
3581keeps libev from including F<config.h>, and it also defines dummy 3599keeps libev from including F<config.h>, and it also defines dummy
3582implementations for some libevent functions (such as logging, which is not 3600implementations for some libevent functions (such as logging, which is not
3583supported). It will also not define any of the structs usually found in 3601supported). It will also not define any of the structs usually found in
3584F<event.h> that are not directly supported by the libev core alone. 3602F<event.h> that are not directly supported by the libev core alone.
3585 3603
3586In stanbdalone mode, libev will still try to automatically deduce the 3604In standalone mode, libev will still try to automatically deduce the
3587configuration, but has to be more conservative. 3605configuration, but has to be more conservative.
3588 3606
3589=item EV_USE_MONOTONIC 3607=item EV_USE_MONOTONIC
3590 3608
3591If defined to be C<1>, libev will try to detect the availability of the 3609If defined to be C<1>, libev will try to detect the availability of the
3656be used is the winsock select). This means that it will call 3674be used is the winsock select). This means that it will call
3657C<_get_osfhandle> on the fd to convert it to an OS handle. Otherwise, 3675C<_get_osfhandle> on the fd to convert it to an OS handle. Otherwise,
3658it is assumed that all these functions actually work on fds, even 3676it is assumed that all these functions actually work on fds, even
3659on win32. Should not be defined on non-win32 platforms. 3677on win32. Should not be defined on non-win32 platforms.
3660 3678
3661=item EV_FD_TO_WIN32_HANDLE 3679=item EV_FD_TO_WIN32_HANDLE(fd)
3662 3680
3663If C<EV_SELECT_IS_WINSOCKET> is enabled, then libev needs a way to map 3681If C<EV_SELECT_IS_WINSOCKET> is enabled, then libev needs a way to map
3664file descriptors to socket handles. When not defining this symbol (the 3682file descriptors to socket handles. When not defining this symbol (the
3665default), then libev will call C<_get_osfhandle>, which is usually 3683default), then libev will call C<_get_osfhandle>, which is usually
3666correct. In some cases, programs use their own file descriptor management, 3684correct. In some cases, programs use their own file descriptor management,
3667in which case they can provide this function to map fds to socket handles. 3685in which case they can provide this function to map fds to socket handles.
3686
3687=item EV_WIN32_HANDLE_TO_FD(handle)
3688
3689If C<EV_SELECT_IS_WINSOCKET> then libev maps handles to file descriptors
3690using the standard C<_open_osfhandle> function. For programs implementing
3691their own fd to handle mapping, overwriting this function makes it easier
3692to do so. This can be done by defining this macro to an appropriate value.
3693
3694=item EV_WIN32_CLOSE_FD(fd)
3695
3696If programs implement their own fd to handle mapping on win32, then this
3697macro can be used to override the C<close> function, useful to unregister
3698file descriptors again. Note that the replacement function has to close
3699the underlying OS handle.
3668 3700
3669=item EV_USE_POLL 3701=item EV_USE_POLL
3670 3702
3671If defined to be C<1>, libev will compile in support for the C<poll>(2) 3703If defined to be C<1>, libev will compile in support for the C<poll>(2)
3672backend. Otherwise it will be enabled on non-win32 platforms. It 3704backend. Otherwise it will be enabled on non-win32 platforms. It

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