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Revision 1.86 by root, Tue Dec 18 01:20:33 2007 UTC vs.
Revision 1.92 by root, Fri Dec 21 01:26:04 2007 UTC

53The newest version of this document is also available as a html-formatted 53The newest version of this document is also available as a html-formatted
54web page you might find easier to navigate when reading it for the first 54web page you might find easier to navigate when reading it for the first
55time: L<http://cvs.schmorp.de/libev/ev.html>. 55time: L<http://cvs.schmorp.de/libev/ev.html>.
56 56
57Libev is an event loop: you register interest in certain events (such as a 57Libev is an event loop: you register interest in certain events (such as a
58file descriptor being readable or a timeout occuring), and it will manage 58file descriptor being readable or a timeout occurring), and it will manage
59these event sources and provide your program with events. 59these event sources and provide your program with events.
60 60
61To do this, it must take more or less complete control over your process 61To do this, it must take more or less complete control over your process
62(or thread) by executing the I<event loop> handler, and will then 62(or thread) by executing the I<event loop> handler, and will then
63communicate events via a callback mechanism. 63communicate events via a callback mechanism.
331 331
332=item C<EVBACKEND_KQUEUE> (value 8, most BSD clones) 332=item C<EVBACKEND_KQUEUE> (value 8, most BSD clones)
333 333
334Kqueue deserves special mention, as at the time of this writing, it 334Kqueue deserves special mention, as at the time of this writing, it
335was broken on all BSDs except NetBSD (usually it doesn't work with 335was broken on all BSDs except NetBSD (usually it doesn't work with
336anything but sockets and pipes, except on Darwin, where of course its 336anything but sockets and pipes, except on Darwin, where of course it's
337completely useless). For this reason its not being "autodetected" 337completely useless). For this reason it's not being "autodetected"
338unless you explicitly specify it explicitly in the flags (i.e. using 338unless you explicitly specify it explicitly in the flags (i.e. using
339C<EVBACKEND_KQUEUE>). 339C<EVBACKEND_KQUEUE>).
340 340
341It scales in the same way as the epoll backend, but the interface to the 341It scales in the same way as the epoll backend, but the interface to the
342kernel is more efficient (which says nothing about its actual speed, of 342kernel is more efficient (which says nothing about its actual speed, of
404Destroys the default loop again (frees all memory and kernel state 404Destroys the default loop again (frees all memory and kernel state
405etc.). None of the active event watchers will be stopped in the normal 405etc.). None of the active event watchers will be stopped in the normal
406sense, so e.g. C<ev_is_active> might still return true. It is your 406sense, so e.g. C<ev_is_active> might still return true. It is your
407responsibility to either stop all watchers cleanly yoursef I<before> 407responsibility to either stop all watchers cleanly yoursef I<before>
408calling this function, or cope with the fact afterwards (which is usually 408calling this function, or cope with the fact afterwards (which is usually
409the easiest thing, youc na just ignore the watchers and/or C<free ()> them 409the easiest thing, you can just ignore the watchers and/or C<free ()> them
410for example). 410for example).
411
412Note that certain global state, such as signal state, will not be freed by
413this function, and related watchers (such as signal and child watchers)
414would need to be stopped manually.
415
416In general it is not advisable to call this function except in the
417rare occasion where you really need to free e.g. the signal handling
418pipe fds. If you need dynamically allocated loops it is better to use
419C<ev_loop_new> and C<ev_loop_destroy>).
411 420
412=item ev_loop_destroy (loop) 421=item ev_loop_destroy (loop)
413 422
414Like C<ev_default_destroy>, but destroys an event loop created by an 423Like C<ev_default_destroy>, but destroys an event loop created by an
415earlier call to C<ev_loop_new>. 424earlier call to C<ev_loop_new>.
460 469
461Returns the current "event loop time", which is the time the event loop 470Returns the current "event loop time", which is the time the event loop
462received events and started processing them. This timestamp does not 471received events and started processing them. This timestamp does not
463change as long as callbacks are being processed, and this is also the base 472change as long as callbacks are being processed, and this is also the base
464time used for relative timers. You can treat it as the timestamp of the 473time used for relative timers. You can treat it as the timestamp of the
465event occuring (or more correctly, libev finding out about it). 474event occurring (or more correctly, libev finding out about it).
466 475
467=item ev_loop (loop, int flags) 476=item ev_loop (loop, int flags)
468 477
469Finally, this is it, the event handler. This function usually is called 478Finally, this is it, the event handler. This function usually is called
470after you initialised all your watchers and you want to start handling 479after you initialised all your watchers and you want to start handling
1782 1791
1783Make a single, non-blocking sweep over the embedded loop. This works 1792Make a single, non-blocking sweep over the embedded loop. This works
1784similarly to C<ev_loop (embedded_loop, EVLOOP_NONBLOCK)>, but in the most 1793similarly to C<ev_loop (embedded_loop, EVLOOP_NONBLOCK)>, but in the most
1785apropriate way for embedded loops. 1794apropriate way for embedded loops.
1786 1795
1787=item struct ev_loop *loop [read-only] 1796=item struct ev_loop *other [read-only]
1788 1797
1789The embedded event loop. 1798The embedded event loop.
1790 1799
1791=back 1800=back
1792 1801
2131Libev can (and often is) directly embedded into host 2140Libev can (and often is) directly embedded into host
2132applications. Examples of applications that embed it include the Deliantra 2141applications. Examples of applications that embed it include the Deliantra
2133Game Server, the EV perl module, the GNU Virtual Private Ethernet (gvpe) 2142Game Server, the EV perl module, the GNU Virtual Private Ethernet (gvpe)
2134and rxvt-unicode. 2143and rxvt-unicode.
2135 2144
2136The goal is to enable you to just copy the neecssary files into your 2145The goal is to enable you to just copy the necessary files into your
2137source directory without having to change even a single line in them, so 2146source directory without having to change even a single line in them, so
2138you can easily upgrade by simply copying (or having a checked-out copy of 2147you can easily upgrade by simply copying (or having a checked-out copy of
2139libev somewhere in your source tree). 2148libev somewhere in your source tree).
2140 2149
2141=head2 FILESETS 2150=head2 FILESETS
2231 2240
2232If defined to be C<1>, libev will try to detect the availability of the 2241If defined to be C<1>, libev will try to detect the availability of the
2233monotonic clock option at both compiletime and runtime. Otherwise no use 2242monotonic clock option at both compiletime and runtime. Otherwise no use
2234of the monotonic clock option will be attempted. If you enable this, you 2243of the monotonic clock option will be attempted. If you enable this, you
2235usually have to link against librt or something similar. Enabling it when 2244usually have to link against librt or something similar. Enabling it when
2236the functionality isn't available is safe, though, althoguh you have 2245the functionality isn't available is safe, though, although you have
2237to make sure you link against any libraries where the C<clock_gettime> 2246to make sure you link against any libraries where the C<clock_gettime>
2238function is hiding in (often F<-lrt>). 2247function is hiding in (often F<-lrt>).
2239 2248
2240=item EV_USE_REALTIME 2249=item EV_USE_REALTIME
2241 2250
2242If defined to be C<1>, libev will try to detect the availability of the 2251If defined to be C<1>, libev will try to detect the availability of the
2243realtime clock option at compiletime (and assume its availability at 2252realtime clock option at compiletime (and assume its availability at
2244runtime if successful). Otherwise no use of the realtime clock option will 2253runtime if successful). Otherwise no use of the realtime clock option will
2245be attempted. This effectively replaces C<gettimeofday> by C<clock_get 2254be attempted. This effectively replaces C<gettimeofday> by C<clock_get
2246(CLOCK_REALTIME, ...)> and will not normally affect correctness. See tzhe note about libraries 2255(CLOCK_REALTIME, ...)> and will not normally affect correctness. See the
2247in the description of C<EV_USE_MONOTONIC>, though. 2256note about libraries in the description of C<EV_USE_MONOTONIC>, though.
2248 2257
2249=item EV_USE_SELECT 2258=item EV_USE_SELECT
2250 2259
2251If undefined or defined to be C<1>, libev will compile in support for the 2260If undefined or defined to be C<1>, libev will compile in support for the
2252C<select>(2) backend. No attempt at autodetection will be done: if no 2261C<select>(2) backend. No attempt at autodetection will be done: if no
2431 2440
2432=item ev_set_cb (ev, cb) 2441=item ev_set_cb (ev, cb)
2433 2442
2434Can be used to change the callback member declaration in each watcher, 2443Can be used to change the callback member declaration in each watcher,
2435and the way callbacks are invoked and set. Must expand to a struct member 2444and the way callbacks are invoked and set. Must expand to a struct member
2436definition and a statement, respectively. See the F<ev.v> header file for 2445definition and a statement, respectively. See the F<ev.c> header file for
2437their default definitions. One possible use for overriding these is to 2446their default definitions. One possible use for overriding these is to
2438avoid the C<struct ev_loop *> as first argument in all cases, or to use 2447avoid the C<struct ev_loop *> as first argument in all cases, or to use
2439method calls instead of plain function calls in C++. 2448method calls instead of plain function calls in C++.
2449
2450=head2 EXPORTED API SYMBOLS
2451
2452If you need to re-export the API (e.g. via a dll) and you need a list of
2453exported symbols, you can use the provided F<Symbol.*> files which list
2454all public symbols, one per line:
2455
2456 Symbols.ev for libev proper
2457 Symbols.event for the libevent emulation
2458
2459This can also be used to rename all public symbols to avoid clashes with
2460multiple versions of libev linked together (which is obviously bad in
2461itself, but sometimes it is inconvinient to avoid this).
2462
2463A sed command like this will create wrapper C<#define>'s that you need to
2464include before including F<ev.h>:
2465
2466 <Symbols.ev sed -e "s/.*/#define & myprefix_&/" >wrap.h
2467
2468This would create a file F<wrap.h> which essentially looks like this:
2469
2470 #define ev_backend myprefix_ev_backend
2471 #define ev_check_start myprefix_ev_check_start
2472 #define ev_check_stop myprefix_ev_check_stop
2473 ...
2440 2474
2441=head2 EXAMPLES 2475=head2 EXAMPLES
2442 2476
2443For a real-world example of a program the includes libev 2477For a real-world example of a program the includes libev
2444verbatim, you can have a look at the EV perl module 2478verbatim, you can have a look at the EV perl module

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