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82 82
83=head1 WHAT TO READ WHEN IN A HURRY 83=head1 WHAT TO READ WHEN IN A HURRY
84 84
85This manual tries to be very detailed, but unfortunately, this also makes 85This manual tries to be very detailed, but unfortunately, this also makes
86it very long. If you just want to know the basics of libev, I suggest 86it very long. If you just want to know the basics of libev, I suggest
87reading L<ANATOMY OF A WATCHER>, then the L<EXAMPLE PROGRAM> above and 87reading L</ANATOMY OF A WATCHER>, then the L</EXAMPLE PROGRAM> above and
88look up the missing functions in L<GLOBAL FUNCTIONS> and the C<ev_io> and 88look up the missing functions in L</GLOBAL FUNCTIONS> and the C<ev_io> and
89C<ev_timer> sections in L<WATCHER TYPES>. 89C<ev_timer> sections in L</WATCHER TYPES>.
90 90
91=head1 ABOUT LIBEV 91=head1 ABOUT LIBEV
92 92
93Libev is an event loop: you register interest in certain events (such as a 93Libev is an event loop: you register interest in certain events (such as a
94file descriptor being readable or a timeout occurring), and it will manage 94file descriptor being readable or a timeout occurring), and it will manage
764 764
765This function is rarely useful, but when some event callback runs for a 765This function is rarely useful, but when some event callback runs for a
766very long time without entering the event loop, updating libev's idea of 766very long time without entering the event loop, updating libev's idea of
767the current time is a good idea. 767the current time is a good idea.
768 768
769See also L<The special problem of time updates> in the C<ev_timer> section. 769See also L</The special problem of time updates> in the C<ev_timer> section.
770 770
771=item ev_suspend (loop) 771=item ev_suspend (loop)
772 772
773=item ev_resume (loop) 773=item ev_resume (loop)
774 774
1346or might not have been clamped to the valid range. 1346or might not have been clamped to the valid range.
1347 1347
1348The default priority used by watchers when no priority has been set is 1348The default priority used by watchers when no priority has been set is
1349always C<0>, which is supposed to not be too high and not be too low :). 1349always C<0>, which is supposed to not be too high and not be too low :).
1350 1350
1351See L<WATCHER PRIORITY MODELS>, below, for a more thorough treatment of 1351See L</WATCHER PRIORITY MODELS>, below, for a more thorough treatment of
1352priorities. 1352priorities.
1353 1353
1354=item ev_invoke (loop, ev_TYPE *watcher, int revents) 1354=item ev_invoke (loop, ev_TYPE *watcher, int revents)
1355 1355
1356Invoke the C<watcher> with the given C<loop> and C<revents>. Neither 1356Invoke the C<watcher> with the given C<loop> and C<revents>. Neither
1381See also C<ev_feed_fd_event> and C<ev_feed_signal_event> for related 1381See also C<ev_feed_fd_event> and C<ev_feed_signal_event> for related
1382functions that do not need a watcher. 1382functions that do not need a watcher.
1383 1383
1384=back 1384=back
1385 1385
1386See also the L<ASSOCIATING CUSTOM DATA WITH A WATCHER> and L<BUILDING YOUR 1386See also the L</ASSOCIATING CUSTOM DATA WITH A WATCHER> and L</BUILDING YOUR
1387OWN COMPOSITE WATCHERS> idioms. 1387OWN COMPOSITE WATCHERS> idioms.
1388 1388
1389=head2 WATCHER STATES 1389=head2 WATCHER STATES
1390 1390
1391There are various watcher states mentioned throughout this manual - 1391There are various watcher states mentioned throughout this manual -
2136=item If the timer is repeating, make the C<repeat> value the new timeout 2136=item If the timer is repeating, make the C<repeat> value the new timeout
2137and start the timer, if necessary. 2137and start the timer, if necessary.
2138 2138
2139=back 2139=back
2140 2140
2141This sounds a bit complicated, see L<Be smart about timeouts>, above, for a 2141This sounds a bit complicated, see L</Be smart about timeouts>, above, for a
2142usage example. 2142usage example.
2143 2143
2144=item ev_tstamp ev_timer_remaining (loop, ev_timer *) 2144=item ev_tstamp ev_timer_remaining (loop, ev_timer *)
2145 2145
2146Returns the remaining time until a timer fires. If the timer is active, 2146Returns the remaining time until a timer fires. If the timer is active,
2858 2858
2859This mode of operation can be useful together with an C<ev_check> watcher, 2859This mode of operation can be useful together with an C<ev_check> watcher,
2860to do something on each event loop iteration - for example to balance load 2860to do something on each event loop iteration - for example to balance load
2861between different connections. 2861between different connections.
2862 2862
2863See L<< Abusing an C<ev_check> watcher for its side-effect >> for a longer 2863See L</Abusing an ev_check watcher for its side-effect> for a longer
2864example. 2864example.
2865 2865
2866=head3 Watcher-Specific Functions and Data Members 2866=head3 Watcher-Specific Functions and Data Members
2867 2867
2868=over 4 2868=over 4
3888You can do similar tricks if you have, say, threads with an event queue - 3888You can do similar tricks if you have, say, threads with an event queue -
3889instead of storing a coroutine, you store the queue object and instead of 3889instead of storing a coroutine, you store the queue object and instead of
3890switching to a coroutine, you push the watcher onto the queue and notify 3890switching to a coroutine, you push the watcher onto the queue and notify
3891any waiters. 3891any waiters.
3892 3892
3893To embed libev, see L<EMBEDDING>, but in short, it's easiest to create two 3893To embed libev, see L</EMBEDDING>, but in short, it's easiest to create two
3894files, F<my_ev.h> and F<my_ev.c> that include the respective libev files: 3894files, F<my_ev.h> and F<my_ev.c> that include the respective libev files:
3895 3895
3896 // my_ev.h 3896 // my_ev.h
3897 #define EV_CB_DECLARE(type) struct my_coro *cb; 3897 #define EV_CB_DECLARE(type) struct my_coro *cb;
3898 #define EV_CB_INVOKE(watcher) switch_to ((watcher)->cb); 3898 #define EV_CB_INVOKE(watcher) switch_to ((watcher)->cb);
3950libev sources can be compiled as C++. Therefore, code that uses the C API 3950libev sources can be compiled as C++. Therefore, code that uses the C API
3951will work fine. 3951will work fine.
3952 3952
3953Proper exception specifications might have to be added to callbacks passed 3953Proper exception specifications might have to be added to callbacks passed
3954to libev: exceptions may be thrown only from watcher callbacks, all 3954to libev: exceptions may be thrown only from watcher callbacks, all
3955other callbacks (allocator, syserr, loop acquire/release and periodioc 3955other callbacks (allocator, syserr, loop acquire/release and periodic
3956reschedule callbacks) must not throw exceptions, and might need a C<throw 3956reschedule callbacks) must not throw exceptions, and might need a C<throw
3957()> specification. If you have code that needs to be compiled as both C 3957()> specification. If you have code that needs to be compiled as both C
3958and C++ you can use the C<EV_THROW> macro for this: 3958and C++ you can use the C<EV_THROW> macro for this:
3959 3959
3960 static void 3960 static void
4121Associates a different C<struct ev_loop> with this watcher. You can only 4121Associates a different C<struct ev_loop> with this watcher. You can only
4122do this when the watcher is inactive (and not pending either). 4122do this when the watcher is inactive (and not pending either).
4123 4123
4124=item w->set ([arguments]) 4124=item w->set ([arguments])
4125 4125
4126Basically the same as C<ev_TYPE_set>, with the same arguments. Either this 4126Basically the same as C<ev_TYPE_set> (except for C<ev::embed> watchers>),
4127method or a suitable start method must be called at least once. Unlike the 4127with the same arguments. Either this method or a suitable start method
4128C counterpart, an active watcher gets automatically stopped and restarted 4128must be called at least once. Unlike the C counterpart, an active watcher
4129when reconfiguring it with this method. 4129gets automatically stopped and restarted when reconfiguring it with this
4130method.
4131
4132For C<ev::embed> watchers this method is called C<set_embed>, to avoid
4133clashing with the C<set (loop)> method.
4130 4134
4131=item w->start () 4135=item w->start ()
4132 4136
4133Starts the watcher. Note that there is no C<loop> argument, as the 4137Starts the watcher. Note that there is no C<loop> argument, as the
4134constructor already stores the event loop. 4138constructor already stores the event loop.
4237=item Lua 4241=item Lua
4238 4242
4239Brian Maher has written a partial interface to libev for lua (at the 4243Brian Maher has written a partial interface to libev for lua (at the
4240time of this writing, only C<ev_io> and C<ev_timer>), to be found at 4244time of this writing, only C<ev_io> and C<ev_timer>), to be found at
4241L<http://github.com/brimworks/lua-ev>. 4245L<http://github.com/brimworks/lua-ev>.
4246
4247=item Javascript
4248
4249Node.js (L<http://nodejs.org>) uses libev as the underlying event library.
4250
4251=item Others
4252
4253There are others, and I stopped counting.
4242 4254
4243=back 4255=back
4244 4256
4245 4257
4246=head1 MACRO MAGIC 4258=head1 MACRO MAGIC
4545 4557
4546If programs implement their own fd to handle mapping on win32, then this 4558If programs implement their own fd to handle mapping on win32, then this
4547macro can be used to override the C<close> function, useful to unregister 4559macro can be used to override the C<close> function, useful to unregister
4548file descriptors again. Note that the replacement function has to close 4560file descriptors again. Note that the replacement function has to close
4549the underlying OS handle. 4561the underlying OS handle.
4562
4563=item EV_USE_WSASOCKET
4564
4565If defined to be C<1>, libev will use C<WSASocket> to create its internal
4566communication socket, which works better in some environments. Otherwise,
4567the normal C<socket> function will be used, which works better in other
4568environments.
4550 4569
4551=item EV_USE_POLL 4570=item EV_USE_POLL
4552 4571
4553If defined to be C<1>, libev will compile in support for the C<poll>(2) 4572If defined to be C<1>, libev will compile in support for the C<poll>(2)
4554backend. Otherwise it will be enabled on non-win32 platforms. It 4573backend. Otherwise it will be enabled on non-win32 platforms. It
4993default loop and triggering an C<ev_async> watcher from the default loop 5012default loop and triggering an C<ev_async> watcher from the default loop
4994watcher callback into the event loop interested in the signal. 5013watcher callback into the event loop interested in the signal.
4995 5014
4996=back 5015=back
4997 5016
4998See also L<THREAD LOCKING EXAMPLE>. 5017See also L</THREAD LOCKING EXAMPLE>.
4999 5018
5000=head3 COROUTINES 5019=head3 COROUTINES
5001 5020
5002Libev is very accommodating to coroutines ("cooperative threads"): 5021Libev is very accommodating to coroutines ("cooperative threads"):
5003libev fully supports nesting calls to its functions from different 5022libev fully supports nesting calls to its functions from different
5409=over 4 5428=over 4
5410 5429
5411=item C<EV_COMPAT3> backwards compatibility mechanism 5430=item C<EV_COMPAT3> backwards compatibility mechanism
5412 5431
5413The backward compatibility mechanism can be controlled by 5432The backward compatibility mechanism can be controlled by
5414C<EV_COMPAT3>. See L<PREPROCESSOR SYMBOLS/MACROS> in the L<EMBEDDING> 5433C<EV_COMPAT3>. See L</PREPROCESSOR SYMBOLS/MACROS> in the L</EMBEDDING>
5415section. 5434section.
5416 5435
5417=item C<ev_default_destroy> and C<ev_default_fork> have been removed 5436=item C<ev_default_destroy> and C<ev_default_fork> have been removed
5418 5437
5419These calls can be replaced easily by their C<ev_loop_xxx> counterparts: 5438These calls can be replaced easily by their C<ev_loop_xxx> counterparts:
5462=over 4 5481=over 4
5463 5482
5464=item active 5483=item active
5465 5484
5466A watcher is active as long as it has been started and not yet stopped. 5485A watcher is active as long as it has been started and not yet stopped.
5467See L<WATCHER STATES> for details. 5486See L</WATCHER STATES> for details.
5468 5487
5469=item application 5488=item application
5470 5489
5471In this document, an application is whatever is using libev. 5490In this document, an application is whatever is using libev.
5472 5491
5508watchers and events. 5527watchers and events.
5509 5528
5510=item pending 5529=item pending
5511 5530
5512A watcher is pending as soon as the corresponding event has been 5531A watcher is pending as soon as the corresponding event has been
5513detected. See L<WATCHER STATES> for details. 5532detected. See L</WATCHER STATES> for details.
5514 5533
5515=item real time 5534=item real time
5516 5535
5517The physical time that is observed. It is apparently strictly monotonic :) 5536The physical time that is observed. It is apparently strictly monotonic :)
5518 5537

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