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4	<head>	4	<head>
5	<title>libev</title>	5	<title>libev</title>
6	<meta name="description" content="Pod documentation for libev" />	6	<meta name="description" content="Pod documentation for libev" />
7	<meta name="inputfile" content="<standard input>" />	7	<meta name="inputfile" content="<standard input>" />
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9	<meta name="created" content="Sat Nov 24 05:58:35 2007" />	9	<meta name="created" content="Mon Nov 26 10:52:13 2007" />
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12	<body>	12	<body>
13	<div class="pod">	13	<div class="pod">
14	<!-- INDEX START -->	14	<!-- INDEX START -->
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21	<li><a href="#CONVENTIONS">CONVENTIONS</a></li>	21	<li><a href="#CONVENTIONS">CONVENTIONS</a></li>
22	<li><a href="#TIME_REPRESENTATION">TIME REPRESENTATION</a></li>	22	<li><a href="#TIME_REPRESENTATION">TIME REPRESENTATION</a></li>
23	<li><a href="#GLOBAL_FUNCTIONS">GLOBAL FUNCTIONS</a></li>	23	<li><a href="#GLOBAL_FUNCTIONS">GLOBAL FUNCTIONS</a></li>
24	<li><a href="#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP">FUNCTIONS CONTROLLING THE EVENT LOOP</a></li>	24	<li><a href="#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP">FUNCTIONS CONTROLLING THE EVENT LOOP</a></li>
25	<li><a href="#ANATOMY_OF_A_WATCHER">ANATOMY OF A WATCHER</a>	25	<li><a href="#ANATOMY_OF_A_WATCHER">ANATOMY OF A WATCHER</a>
		26	<ul><li><a href="#GENERIC_WATCHER_FUNCTIONS">GENERIC WATCHER FUNCTIONS</a></li>
26	<ul><li><a href="#ASSOCIATING_CUSTOM_DATA_WITH_A_WATCH">ASSOCIATING CUSTOM DATA WITH A WATCHER</a></li>	27	<li><a href="#ASSOCIATING_CUSTOM_DATA_WITH_A_WATCH">ASSOCIATING CUSTOM DATA WITH A WATCHER</a></li>
27	</ul>	28	</ul>
28	</li>	29	</li>
29	<li><a href="#WATCHER_TYPES">WATCHER TYPES</a>	30	<li><a href="#WATCHER_TYPES">WATCHER TYPES</a>
30	<ul><li><a href="#code_ev_io_code_is_this_file_descrip"><code>ev_io</code> - is this file descriptor readable or writable</a></li>	31	<ul><li><a href="#code_ev_io_code_is_this_file_descrip"><code>ev_io</code> - is this file descriptor readable or writable?</a></li>
31	<li><a href="#code_ev_timer_code_relative_and_opti"><code>ev_timer</code> - relative and optionally recurring timeouts</a></li>	32	<li><a href="#code_ev_timer_code_relative_and_opti"><code>ev_timer</code> - relative and optionally repeating timeouts</a></li>
32	<li><a href="#code_ev_periodic_code_to_cron_or_not"><code>ev_periodic</code> - to cron or not to cron</a></li>	33	<li><a href="#code_ev_periodic_code_to_cron_or_not"><code>ev_periodic</code> - to cron or not to cron?</a></li>
33	<li><a href="#code_ev_signal_code_signal_me_when_a"><code>ev_signal</code> - signal me when a signal gets signalled</a></li>	34	<li><a href="#code_ev_signal_code_signal_me_when_a"><code>ev_signal</code> - signal me when a signal gets signalled!</a></li>
34	<li><a href="#code_ev_child_code_wait_for_pid_stat"><code>ev_child</code> - wait for pid status changes</a></li>	35	<li><a href="#code_ev_child_code_watch_out_for_pro"><code>ev_child</code> - watch out for process status changes</a></li>
35	<li><a href="#code_ev_idle_code_when_you_ve_got_no"><code>ev_idle</code> - when you've got nothing better to do</a></li>	36	<li><a href="#code_ev_idle_code_when_you_ve_got_no"><code>ev_idle</code> - when you've got nothing better to do...</a></li>
36	<li><a href="#code_ev_prepare_code_and_code_ev_che"><code>ev_prepare</code> and <code>ev_check</code> - customise your event loop</a></li>	37	<li><a href="#code_ev_prepare_code_and_code_ev_che"><code>ev_prepare</code> and <code>ev_check</code> - customise your event loop!</a></li>
37	<li><a href="#code_ev_embed_code_when_one_backend_"><code>ev_embed</code> - when one backend isn't enough</a></li>	38	<li><a href="#code_ev_embed_code_when_one_backend_"><code>ev_embed</code> - when one backend isn't enough...</a></li>
38	</ul>	39	</ul>
39	</li>	40	</li>
40	<li><a href="#OTHER_FUNCTIONS">OTHER FUNCTIONS</a></li>	41	<li><a href="#OTHER_FUNCTIONS">OTHER FUNCTIONS</a></li>
41	<li><a href="#LIBEVENT_EMULATION">LIBEVENT EMULATION</a></li>	42	<li><a href="#LIBEVENT_EMULATION">LIBEVENT EMULATION</a></li>
42	<li><a href="#C_SUPPORT">C++ SUPPORT</a></li>	43	<li><a href="#C_SUPPORT">C++ SUPPORT</a></li>
		44	<li><a href="#EMBEDDING">EMBEDDING</a>
		45	<ul><li><a href="#FILESETS">FILESETS</a>
		46	<ul><li><a href="#CORE_EVENT_LOOP">CORE EVENT LOOP</a></li>
		47	<li><a href="#LIBEVENT_COMPATIBILITY_API">LIBEVENT COMPATIBILITY API</a></li>
		48	<li><a href="#AUTOCONF_SUPPORT">AUTOCONF SUPPORT</a></li>
		49	</ul>
		50	</li>
		51	<li><a href="#PREPROCESSOR_SYMBOLS_MACROS">PREPROCESSOR SYMBOLS/MACROS</a></li>
		52	<li><a href="#EXAMPLES">EXAMPLES</a></li>
		53	</ul>
		54	</li>
43	<li><a href="#AUTHOR">AUTHOR</a>	55	<li><a href="#AUTHOR">AUTHOR</a>
44	</li>	56	</li>
45	</ul><hr />	57	</ul><hr />
46	<!-- INDEX END -->	58	<!-- INDEX END -->
47		59
…		…
363	</pre>	375	</pre>
364	</dd>	376	</dd>
365	<dt>ev_default_destroy ()</dt>	377	<dt>ev_default_destroy ()</dt>
366	<dd>	378	<dd>
367	<p>Destroys the default loop again (frees all memory and kernel state	379	<p>Destroys the default loop again (frees all memory and kernel state
368	etc.). This stops all registered event watchers (by not touching them in	380	etc.). None of the active event watchers will be stopped in the normal
369	any way whatsoever, although you cannot rely on this :).</p>	381	sense, so e.g. <code>ev_is_active</code> might still return true. It is your
		382	responsibility to either stop all watchers cleanly yoursef <i>before</i>
		383	calling this function, or cope with the fact afterwards (which is usually
		384	the easiest thing, youc na just ignore the watchers and/or <code>free ()</code> them
		385	for example).</p>
370	</dd>	386	</dd>
371	<dt>ev_loop_destroy (loop)</dt>	387	<dt>ev_loop_destroy (loop)</dt>
372	<dd>	388	<dd>
373	<p>Like <code>ev_default_destroy</code>, but destroys an event loop created by an	389	<p>Like <code>ev_default_destroy</code>, but destroys an event loop created by an
374	earlier call to <code>ev_loop_new</code>.</p>	390	earlier call to <code>ev_loop_new</code>.</p>
…		…
497		513
498	</pre>	514	</pre>
499	</dd>	515	</dd>
500	</dl>	516	</dl>
501		517
		518
		519
		520
		521
502	</div>	522	</div>
503	<h1 id="ANATOMY_OF_A_WATCHER">ANATOMY OF A WATCHER</h1><p><a href="#TOP" class="toplink">Top</a></p>	523	<h1 id="ANATOMY_OF_A_WATCHER">ANATOMY OF A WATCHER</h1><p><a href="#TOP" class="toplink">Top</a></p>
504	<div id="ANATOMY_OF_A_WATCHER_CONTENT">	524	<div id="ANATOMY_OF_A_WATCHER_CONTENT">
505	<p>A watcher is a structure that you create and register to record your	525	<p>A watcher is a structure that you create and register to record your
506	interest in some event. For instance, if you want to wait for STDIN to	526	interest in some event. For instance, if you want to wait for STDIN to
…		…
535	with a watcher-specific start function (<code>ev_<type>_start (loop, watcher	555	with a watcher-specific start function (<code>ev_<type>_start (loop, watcher
536	*)</code>), and you can stop watching for events at any time by calling the	556	*)</code>), and you can stop watching for events at any time by calling the
537	corresponding stop function (<code>ev_<type>_stop (loop, watcher *)</code>.</p>	557	corresponding stop function (<code>ev_<type>_stop (loop, watcher *)</code>.</p>
538	<p>As long as your watcher is active (has been started but not stopped) you	558	<p>As long as your watcher is active (has been started but not stopped) you
539	must not touch the values stored in it. Most specifically you must never	559	must not touch the values stored in it. Most specifically you must never
540	reinitialise it or call its set macro.</p>	560	reinitialise it or call its <code>set</code> macro.</p>
541	<p>You can check whether an event is active by calling the <code>ev_is_active
542	(watcher *)</code> macro. To see whether an event is outstanding (but the
543	callback for it has not been called yet) you can use the <code>ev_is_pending
544	(watcher *)</code> macro.</p>
545	<p>Each and every callback receives the event loop pointer as first, the	561	<p>Each and every callback receives the event loop pointer as first, the
546	registered watcher structure as second, and a bitset of received events as	562	registered watcher structure as second, and a bitset of received events as
547	third argument.</p>	563	third argument.</p>
548	<p>The received events usually include a single bit per event type received	564	<p>The received events usually include a single bit per event type received
549	(you can receive multiple events at the same time). The possible bit masks	565	(you can receive multiple events at the same time). The possible bit masks
…		…
598	your callbacks is well-written it can just attempt the operation and cope	614	your callbacks is well-written it can just attempt the operation and cope
599	with the error from read() or write(). This will not work in multithreaded	615	with the error from read() or write(). This will not work in multithreaded
600	programs, though, so beware.</p>	616	programs, though, so beware.</p>
601	</dd>	617	</dd>
602	</dl>	618	</dl>
		619
		620	</div>
		621	<h2 id="GENERIC_WATCHER_FUNCTIONS">GENERIC WATCHER FUNCTIONS</h2>
		622	<div id="GENERIC_WATCHER_FUNCTIONS_CONTENT">
		623	<p>In the following description, <code>TYPE</code> stands for the watcher type,
		624	e.g. <code>timer</code> for <code>ev_timer</code> watchers and <code>io</code> for <code>ev_io</code> watchers.</p>
		625	<dl>
		626	<dt><code>ev_init</code> (ev_TYPE *watcher, callback)</dt>
		627	<dd>
		628	<p>This macro initialises the generic portion of a watcher. The contents
		629	of the watcher object can be arbitrary (so <code>malloc</code> will do). Only
		630	the generic parts of the watcher are initialised, you <i>need</i> to call
		631	the type-specific <code>ev_TYPE_set</code> macro afterwards to initialise the
		632	type-specific parts. For each type there is also a <code>ev_TYPE_init</code> macro
		633	which rolls both calls into one.</p>
		634	<p>You can reinitialise a watcher at any time as long as it has been stopped
		635	(or never started) and there are no pending events outstanding.</p>
		636	<p>The callback is always of type <code>void ()(ev_loop loop, ev_TYPE *watcher,
		637	int revents)</code>.</p>
		638	</dd>
		639	<dt><code>ev_TYPE_set</code> (ev_TYPE *, [args])</dt>
		640	<dd>
		641	<p>This macro initialises the type-specific parts of a watcher. You need to
		642	call <code>ev_init</code> at least once before you call this macro, but you can
		643	call <code>ev_TYPE_set</code> any number of times. You must not, however, call this
		644	macro on a watcher that is active (it can be pending, however, which is a
		645	difference to the <code>ev_init</code> macro).</p>
		646	<p>Although some watcher types do not have type-specific arguments
		647	(e.g. <code>ev_prepare</code>) you still need to call its <code>set</code> macro.</p>
		648	</dd>
		649	<dt><code>ev_TYPE_init</code> (ev_TYPE *watcher, callback, [args])</dt>
		650	<dd>
		651	<p>This convinience macro rolls both <code>ev_init</code> and <code>ev_TYPE_set</code> macro
		652	calls into a single call. This is the most convinient method to initialise
		653	a watcher. The same limitations apply, of course.</p>
		654	</dd>
		655	<dt><code>ev_TYPE_start</code> (loop , ev_TYPE watcher)</dt>
		656	<dd>
		657	<p>Starts (activates) the given watcher. Only active watchers will receive
		658	events. If the watcher is already active nothing will happen.</p>
		659	</dd>
		660	<dt><code>ev_TYPE_stop</code> (loop , ev_TYPE watcher)</dt>
		661	<dd>
		662	<p>Stops the given watcher again (if active) and clears the pending
		663	status. It is possible that stopped watchers are pending (for example,
		664	non-repeating timers are being stopped when they become pending), but
		665	<code>ev_TYPE_stop</code> ensures that the watcher is neither active nor pending. If
		666	you want to free or reuse the memory used by the watcher it is therefore a
		667	good idea to always call its <code>ev_TYPE_stop</code> function.</p>
		668	</dd>
		669	<dt>bool ev_is_active (ev_TYPE *watcher)</dt>
		670	<dd>
		671	<p>Returns a true value iff the watcher is active (i.e. it has been started
		672	and not yet been stopped). As long as a watcher is active you must not modify
		673	it.</p>
		674	</dd>
		675	<dt>bool ev_is_pending (ev_TYPE *watcher)</dt>
		676	<dd>
		677	<p>Returns a true value iff the watcher is pending, (i.e. it has outstanding
		678	events but its callback has not yet been invoked). As long as a watcher
		679	is pending (but not active) you must not call an init function on it (but
		680	<code>ev_TYPE_set</code> is safe) and you must make sure the watcher is available to
		681	libev (e.g. you cnanot <code>free ()</code> it).</p>
		682	</dd>
		683	<dt>callback = ev_cb (ev_TYPE *watcher)</dt>
		684	<dd>
		685	<p>Returns the callback currently set on the watcher.</p>
		686	</dd>
		687	<dt>ev_cb_set (ev_TYPE *watcher, callback)</dt>
		688	<dd>
		689	<p>Change the callback. You can change the callback at virtually any time
		690	(modulo threads).</p>
		691	</dd>
		692	</dl>
		693
		694
		695
		696
603		697
604	</div>	698	</div>
605	<h2 id="ASSOCIATING_CUSTOM_DATA_WITH_A_WATCH">ASSOCIATING CUSTOM DATA WITH A WATCHER</h2>	699	<h2 id="ASSOCIATING_CUSTOM_DATA_WITH_A_WATCH">ASSOCIATING CUSTOM DATA WITH A WATCHER</h2>
606	<div id="ASSOCIATING_CUSTOM_DATA_WITH_A_WATCH-2">	700	<div id="ASSOCIATING_CUSTOM_DATA_WITH_A_WATCH-2">
607	<p>Each watcher has, by default, a member <code>void *data</code> that you can change	701	<p>Each watcher has, by default, a member <code>void *data</code> that you can change
…		…
644		738
645		739
646		740
647		741
648	</div>	742	</div>
649	<h2 id="code_ev_io_code_is_this_file_descrip"><code>ev_io</code> - is this file descriptor readable or writable</h2>	743	<h2 id="code_ev_io_code_is_this_file_descrip"><code>ev_io</code> - is this file descriptor readable or writable?</h2>
650	<div id="code_ev_io_code_is_this_file_descrip-2">	744	<div id="code_ev_io_code_is_this_file_descrip-2">
651	<p>I/O watchers check whether a file descriptor is readable or writable	745	<p>I/O watchers check whether a file descriptor is readable or writable
652	in each iteration of the event loop (This behaviour is called	746	in each iteration of the event loop, or, more precisely, when reading
653	level-triggering because you keep receiving events as long as the	747	would not block the process and writing would at least be able to write
654	condition persists. Remember you can stop the watcher if you don't want to	748	some data. This behaviour is called level-triggering because you keep
655	act on the event and neither want to receive future events).</p>	749	receiving events as long as the condition persists. Remember you can stop
		750	the watcher if you don't want to act on the event and neither want to
		751	receive future events.</p>
656	<p>In general you can register as many read and/or write event watchers per	752	<p>In general you can register as many read and/or write event watchers per
657	fd as you want (as long as you don't confuse yourself). Setting all file	753	fd as you want (as long as you don't confuse yourself). Setting all file
658	descriptors to non-blocking mode is also usually a good idea (but not	754	descriptors to non-blocking mode is also usually a good idea (but not
659	required if you know what you are doing).</p>	755	required if you know what you are doing).</p>
660	<p>You have to be careful with dup'ed file descriptors, though. Some backends	756	<p>You have to be careful with dup'ed file descriptors, though. Some backends
661	(the linux epoll backend is a notable example) cannot handle dup'ed file	757	(the linux epoll backend is a notable example) cannot handle dup'ed file
662	descriptors correctly if you register interest in two or more fds pointing	758	descriptors correctly if you register interest in two or more fds pointing
663	to the same underlying file/socket etc. description (that is, they share	759	to the same underlying file/socket/etc. description (that is, they share
664	the same underlying "file open").</p>	760	the same underlying "file open").</p>
665	<p>If you must do this, then force the use of a known-to-be-good backend	761	<p>If you must do this, then force the use of a known-to-be-good backend
666	(at the time of this writing, this includes only <code>EVBACKEND_SELECT</code> and	762	(at the time of this writing, this includes only <code>EVBACKEND_SELECT</code> and
667	<code>EVBACKEND_POLL</code>).</p>	763	<code>EVBACKEND_POLL</code>).</p>
		764	<p>Another thing you have to watch out for is that it is quite easy to
		765	receive "spurious" readyness notifications, that is your callback might
		766	be called with <code>EV_READ</code> but a subsequent <code>read</code>(2) will actually block
		767	because there is no data. Not only are some backends known to create a
		768	lot of those (for example solaris ports), it is very easy to get into
		769	this situation even with a relatively standard program structure. Thus
		770	it is best to always use non-blocking I/O: An extra <code>read</code>(2) returning
		771	<code>EAGAIN</code> is far preferable to a program hanging until some data arrives.</p>
		772	<p>If you cannot run the fd in non-blocking mode (for example you should not
		773	play around with an Xlib connection), then you have to seperately re-test
		774	wether a file descriptor is really ready with a known-to-be good interface
		775	such as poll (fortunately in our Xlib example, Xlib already does this on
		776	its own, so its quite safe to use).</p>
668	<dl>	777	<dl>
669	<dt>ev_io_init (ev_io *, callback, int fd, int events)</dt>	778	<dt>ev_io_init (ev_io *, callback, int fd, int events)</dt>
670	<dt>ev_io_set (ev_io *, int fd, int events)</dt>	779	<dt>ev_io_set (ev_io *, int fd, int events)</dt>
671	<dd>	780	<dd>
672	<p>Configures an <code>ev_io</code> watcher. The fd is the file descriptor to rceeive	781	<p>Configures an <code>ev_io</code> watcher. The <code>fd</code> is the file descriptor to
673	events for and events is either <code>EV_READ</code>, <code>EV_WRITE</code> or <code>EV_READ \|	782	rceeive events for and events is either <code>EV_READ</code>, <code>EV_WRITE</code> or
674	EV_WRITE</code> to receive the given events.</p>	783	<code>EV_READ \| EV_WRITE</code> to receive the given events.</p>
675	<p>Please note that most of the more scalable backend mechanisms (for example
676	epoll and solaris ports) can result in spurious readyness notifications
677	for file descriptors, so you practically need to use non-blocking I/O (and
678	treat callback invocation as hint only), or retest separately with a safe
679	interface before doing I/O (XLib can do this), or force the use of either
680	<code>EVBACKEND_SELECT</code> or <code>EVBACKEND_POLL</code>, which don't suffer from this
681	problem. Also note that it is quite easy to have your callback invoked
682	when the readyness condition is no longer valid even when employing
683	typical ways of handling events, so its a good idea to use non-blocking
684	I/O unconditionally.</p>
685	</dd>	784	</dd>
686	</dl>	785	</dl>
687	<p>Example: call <code>stdin_readable_cb</code> when STDIN_FILENO has become, well	786	<p>Example: call <code>stdin_readable_cb</code> when STDIN_FILENO has become, well
688	readable, but only once. Since it is likely line-buffered, you could	787	readable, but only once. Since it is likely line-buffered, you could
689	attempt to read a whole line in the callback:</p>	788	attempt to read a whole line in the callback:</p>
…		…
705		804
706		805
707	</pre>	806	</pre>
708		807
709	</div>	808	</div>
710	<h2 id="code_ev_timer_code_relative_and_opti"><code>ev_timer</code> - relative and optionally recurring timeouts</h2>	809	<h2 id="code_ev_timer_code_relative_and_opti"><code>ev_timer</code> - relative and optionally repeating timeouts</h2>
711	<div id="code_ev_timer_code_relative_and_opti-2">	810	<div id="code_ev_timer_code_relative_and_opti-2">
712	<p>Timer watchers are simple relative timers that generate an event after a	811	<p>Timer watchers are simple relative timers that generate an event after a
713	given time, and optionally repeating in regular intervals after that.</p>	812	given time, and optionally repeating in regular intervals after that.</p>
714	<p>The timers are based on real time, that is, if you register an event that	813	<p>The timers are based on real time, that is, if you register an event that
715	times out after an hour and you reset your system clock to last years	814	times out after an hour and you reset your system clock to last years
…		…
791		890
792		891
793	</pre>	892	</pre>
794		893
795	</div>	894	</div>
796	<h2 id="code_ev_periodic_code_to_cron_or_not"><code>ev_periodic</code> - to cron or not to cron</h2>	895	<h2 id="code_ev_periodic_code_to_cron_or_not"><code>ev_periodic</code> - to cron or not to cron?</h2>
797	<div id="code_ev_periodic_code_to_cron_or_not-2">	896	<div id="code_ev_periodic_code_to_cron_or_not-2">
798	<p>Periodic watchers are also timers of a kind, but they are very versatile	897	<p>Periodic watchers are also timers of a kind, but they are very versatile
799	(and unfortunately a bit complex).</p>	898	(and unfortunately a bit complex).</p>
800	<p>Unlike <code>ev_timer</code>'s, they are not based on real time (or relative time)	899	<p>Unlike <code>ev_timer</code>'s, they are not based on real time (or relative time)
801	but on wallclock time (absolute time). You can tell a periodic watcher	900	but on wallclock time (absolute time). You can tell a periodic watcher
802	to trigger "at" some specific point in time. For example, if you tell a	901	to trigger "at" some specific point in time. For example, if you tell a
803	periodic watcher to trigger in 10 seconds (by specifiying e.g. c<ev_now ()	902	periodic watcher to trigger in 10 seconds (by specifiying e.g. <code>ev_now ()
804	+ 10.>) and then reset your system clock to the last year, then it will	903	+ 10.</code>) and then reset your system clock to the last year, then it will
805	take a year to trigger the event (unlike an <code>ev_timer</code>, which would trigger	904	take a year to trigger the event (unlike an <code>ev_timer</code>, which would trigger
806	roughly 10 seconds later and of course not if you reset your system time	905	roughly 10 seconds later and of course not if you reset your system time
807	again).</p>	906	again).</p>
808	<p>They can also be used to implement vastly more complex timers, such as	907	<p>They can also be used to implement vastly more complex timers, such as
809	triggering an event on eahc midnight, local time.</p>	908	triggering an event on eahc midnight, local time.</p>
…		…
920		1019
921		1020
922	</pre>	1021	</pre>
923		1022
924	</div>	1023	</div>
925	<h2 id="code_ev_signal_code_signal_me_when_a"><code>ev_signal</code> - signal me when a signal gets signalled</h2>	1024	<h2 id="code_ev_signal_code_signal_me_when_a"><code>ev_signal</code> - signal me when a signal gets signalled!</h2>
926	<div id="code_ev_signal_code_signal_me_when_a-2">	1025	<div id="code_ev_signal_code_signal_me_when_a-2">
927	<p>Signal watchers will trigger an event when the process receives a specific	1026	<p>Signal watchers will trigger an event when the process receives a specific
928	signal one or more times. Even though signals are very asynchronous, libev	1027	signal one or more times. Even though signals are very asynchronous, libev
929	will try it's best to deliver signals synchronously, i.e. as part of the	1028	will try it's best to deliver signals synchronously, i.e. as part of the
930	normal event processing, like any other event.</p>	1029	normal event processing, like any other event.</p>
…		…
946		1045
947		1046
948		1047
949		1048
950	</div>	1049	</div>
951	<h2 id="code_ev_child_code_wait_for_pid_stat"><code>ev_child</code> - wait for pid status changes</h2>	1050	<h2 id="code_ev_child_code_watch_out_for_pro"><code>ev_child</code> - watch out for process status changes</h2>
952	<div id="code_ev_child_code_wait_for_pid_stat-2">	1051	<div id="code_ev_child_code_watch_out_for_pro-2">
953	<p>Child watchers trigger when your process receives a SIGCHLD in response to	1052	<p>Child watchers trigger when your process receives a SIGCHLD in response to
954	some child status changes (most typically when a child of yours dies).</p>	1053	some child status changes (most typically when a child of yours dies).</p>
955	<dl>	1054	<dl>
956	<dt>ev_child_init (ev_child *, callback, int pid)</dt>	1055	<dt>ev_child_init (ev_child *, callback, int pid)</dt>
957	<dt>ev_child_set (ev_child *, int pid)</dt>	1056	<dt>ev_child_set (ev_child *, int pid)</dt>
…		…
979		1078
980		1079
981	</pre>	1080	</pre>
982		1081
983	</div>	1082	</div>
984	<h2 id="code_ev_idle_code_when_you_ve_got_no"><code>ev_idle</code> - when you've got nothing better to do</h2>	1083	<h2 id="code_ev_idle_code_when_you_ve_got_no"><code>ev_idle</code> - when you've got nothing better to do...</h2>
985	<div id="code_ev_idle_code_when_you_ve_got_no-2">	1084	<div id="code_ev_idle_code_when_you_ve_got_no-2">
986	<p>Idle watchers trigger events when there are no other events are pending	1085	<p>Idle watchers trigger events when there are no other events are pending
987	(prepare, check and other idle watchers do not count). That is, as long	1086	(prepare, check and other idle watchers do not count). That is, as long
988	as your process is busy handling sockets or timeouts (or even signals,	1087	as your process is busy handling sockets or timeouts (or even signals,
989	imagine) it will not be triggered. But when your process is idle all idle	1088	imagine) it will not be triggered. But when your process is idle all idle
…		…
1022		1121
1023		1122
1024	</pre>	1123	</pre>
1025		1124
1026	</div>	1125	</div>
1027	<h2 id="code_ev_prepare_code_and_code_ev_che"><code>ev_prepare</code> and <code>ev_check</code> - customise your event loop</h2>	1126	<h2 id="code_ev_prepare_code_and_code_ev_che"><code>ev_prepare</code> and <code>ev_check</code> - customise your event loop!</h2>
1028	<div id="code_ev_prepare_code_and_code_ev_che-2">	1127	<div id="code_ev_prepare_code_and_code_ev_che-2">
1029	<p>Prepare and check watchers are usually (but not always) used in tandem:	1128	<p>Prepare and check watchers are usually (but not always) used in tandem:
1030	prepare watchers get invoked before the process blocks and check watchers	1129	prepare watchers get invoked before the process blocks and check watchers
1031	afterwards.</p>	1130	afterwards.</p>
		1131	<p>You <i>must not</i> call <code>ev_loop</code> or similar functions that enter
		1132	the current event loop from either <code>ev_prepare</code> or <code>ev_check</code>
		1133	watchers. Other loops than the current one are fine, however. The
		1134	rationale behind this is that you do not need to check for recursion in
		1135	those watchers, i.e. the sequence will always be <code>ev_prepare</code>, blocking,
		1136	<code>ev_check</code> so if you have one watcher of each kind they will always be
		1137	called in pairs bracketing the blocking call.</p>
1032	<p>Their main purpose is to integrate other event mechanisms into libev and	1138	<p>Their main purpose is to integrate other event mechanisms into libev and
1033	their use is somewhat advanced. This could be used, for example, to track	1139	their use is somewhat advanced. This could be used, for example, to track
1034	variable changes, implement your own watchers, integrate net-snmp or a	1140	variable changes, implement your own watchers, integrate net-snmp or a
1035	coroutine library and lots more.</p>	1141	coroutine library and lots more. They are also occasionally useful if
		1142	you cache some data and want to flush it before blocking (for example,
		1143	in X programs you might want to do an <code>XFlush ()</code> in an <code>ev_prepare</code>
		1144	watcher).</p>
1036	<p>This is done by examining in each prepare call which file descriptors need	1145	<p>This is done by examining in each prepare call which file descriptors need
1037	to be watched by the other library, registering <code>ev_io</code> watchers for	1146	to be watched by the other library, registering <code>ev_io</code> watchers for
1038	them and starting an <code>ev_timer</code> watcher for any timeouts (many libraries	1147	them and starting an <code>ev_timer</code> watcher for any timeouts (many libraries
1039	provide just this functionality). Then, in the check watcher you check for	1148	provide just this functionality). Then, in the check watcher you check for
1040	any events that occured (by checking the pending status of all watchers	1149	any events that occured (by checking the pending status of all watchers
…		…
1056	<p>Initialises and configures the prepare or check watcher - they have no	1165	<p>Initialises and configures the prepare or check watcher - they have no
1057	parameters of any kind. There are <code>ev_prepare_set</code> and <code>ev_check_set</code>	1166	parameters of any kind. There are <code>ev_prepare_set</code> and <code>ev_check_set</code>
1058	macros, but using them is utterly, utterly and completely pointless.</p>	1167	macros, but using them is utterly, utterly and completely pointless.</p>
1059	</dd>	1168	</dd>
1060	</dl>	1169	</dl>
1061	<p>Example: TODO.</p>	1170	<p>Example: To include a library such as adns, you would add IO watchers
		1171	and a timeout watcher in a prepare handler, as required by libadns, and
		1172	in a check watcher, destroy them and call into libadns. What follows is
		1173	pseudo-code only of course:</p>
		1174	<pre> static ev_io iow [nfd];
		1175	static ev_timer tw;
1062		1176
		1177	static void
		1178	io_cb (ev_loop loop, ev_io w, int revents)
		1179	{
		1180	// set the relevant poll flags
		1181	struct pollfd fd = (struct pollfd )w->data;
		1182	if (revents & EV_READ ) fd->revents \|= fd->events & POLLIN;
		1183	if (revents & EV_WRITE) fd->revents \|= fd->events & POLLOUT;
		1184	}
1063		1185
		1186	// create io watchers for each fd and a timer before blocking
		1187	static void
		1188	adns_prepare_cb (ev_loop loop, ev_prepare w, int revents)
		1189	{
		1190	int timeout = 3600000;truct pollfd fds [nfd];
		1191	// actual code will need to loop here and realloc etc.
		1192	adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ()));
1064		1193
		1194	/* the callback is illegal, but won't be called as we stop during check */
		1195	ev_timer_init (&tw, 0, timeout * 1e-3);
		1196	ev_timer_start (loop, &tw);
1065		1197
		1198	// create on ev_io per pollfd
		1199	for (int i = 0; i < nfd; ++i)
		1200	{
		1201	ev_io_init (iow + i, io_cb, fds [i].fd,
		1202	((fds [i].events & POLLIN ? EV_READ : 0)
		1203	\| (fds [i].events & POLLOUT ? EV_WRITE : 0)));
1066		1204
		1205	fds [i].revents = 0;
		1206	iow [i].data = fds + i;
		1207	ev_io_start (loop, iow + i);
		1208	}
		1209	}
		1210
		1211	// stop all watchers after blocking
		1212	static void
		1213	adns_check_cb (ev_loop loop, ev_check w, int revents)
		1214	{
		1215	ev_timer_stop (loop, &tw);
		1216
		1217	for (int i = 0; i < nfd; ++i)
		1218	ev_io_stop (loop, iow + i);
		1219
		1220	adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop));
		1221	}
		1222
		1223
		1224
		1225
		1226	</pre>
		1227
1067	</div>	1228	</div>
1068	<h2 id="code_ev_embed_code_when_one_backend_"><code>ev_embed</code> - when one backend isn't enough</h2>	1229	<h2 id="code_ev_embed_code_when_one_backend_"><code>ev_embed</code> - when one backend isn't enough...</h2>
1069	<div id="code_ev_embed_code_when_one_backend_-2">	1230	<div id="code_ev_embed_code_when_one_backend_-2">
1070	<p>This is a rather advanced watcher type that lets you embed one event loop	1231	<p>This is a rather advanced watcher type that lets you embed one event loop
1071	into another.</p>	1232	into another (currently only <code>ev_io</code> events are supported in the embedded
		1233	loop, other types of watchers might be handled in a delayed or incorrect
		1234	fashion and must not be used).</p>
1072	<p>There are primarily two reasons you would want that: work around bugs and	1235	<p>There are primarily two reasons you would want that: work around bugs and
1073	prioritise I/O.</p>	1236	prioritise I/O.</p>
1074	<p>As an example for a bug workaround, the kqueue backend might only support	1237	<p>As an example for a bug workaround, the kqueue backend might only support
1075	sockets on some platform, so it is unusable as generic backend, but you	1238	sockets on some platform, so it is unusable as generic backend, but you
1076	still want to make use of it because you have many sockets and it scales	1239	still want to make use of it because you have many sockets and it scales
…		…
1081	<p>As for prioritising I/O: rarely you have the case where some fds have	1244	<p>As for prioritising I/O: rarely you have the case where some fds have
1082	to be watched and handled very quickly (with low latency), and even	1245	to be watched and handled very quickly (with low latency), and even
1083	priorities and idle watchers might have too much overhead. In this case	1246	priorities and idle watchers might have too much overhead. In this case
1084	you would put all the high priority stuff in one loop and all the rest in	1247	you would put all the high priority stuff in one loop and all the rest in
1085	a second one, and embed the second one in the first.</p>	1248	a second one, and embed the second one in the first.</p>
		1249	<p>As long as the watcher is active, the callback will be invoked every time
		1250	there might be events pending in the embedded loop. The callback must then
		1251	call <code>ev_embed_sweep (mainloop, watcher)</code> to make a single sweep and invoke
		1252	their callbacks (you could also start an idle watcher to give the embedded
		1253	loop strictly lower priority for example). You can also set the callback
		1254	to <code>0</code>, in which case the embed watcher will automatically execute the
		1255	embedded loop sweep.</p>
1086	<p>As long as the watcher is started it will automatically handle events. The	1256	<p>As long as the watcher is started it will automatically handle events. The
1087	callback will be invoked whenever some events have been handled. You can	1257	callback will be invoked whenever some events have been handled. You can
1088	set the callback to <code>0</code> to avoid having to specify one if you are not	1258	set the callback to <code>0</code> to avoid having to specify one if you are not
1089	interested in that.</p>	1259	interested in that.</p>
1090	<p>Also, there have not currently been made special provisions for forking:	1260	<p>Also, there have not currently been made special provisions for forking:
…		…
1117	else	1287	else
1118	loop_lo = loop_hi;	1288	loop_lo = loop_hi;
1119		1289
1120	</pre>	1290	</pre>
1121	<dl>	1291	<dl>
1122	<dt>ev_embed_init (ev_embed , callback, struct ev_loop loop)</dt>	1292	<dt>ev_embed_init (ev_embed , callback, struct ev_loop embedded_loop)</dt>
1123	<dt>ev_embed_set (ev_embed , callback, struct ev_loop loop)</dt>	1293	<dt>ev_embed_set (ev_embed , callback, struct ev_loop embedded_loop)</dt>
		1294	<dd>
		1295	<p>Configures the watcher to embed the given loop, which must be
		1296	embeddable. If the callback is <code>0</code>, then <code>ev_embed_sweep</code> will be
		1297	invoked automatically, otherwise it is the responsibility of the callback
		1298	to invoke it (it will continue to be called until the sweep has been done,
		1299	if you do not want thta, you need to temporarily stop the embed watcher).</p>
1124	<dd>	1300	</dd>
1125	<p>Configures the watcher to embed the given loop, which must be embeddable.</p>	1301	<dt>ev_embed_sweep (loop, ev_embed *)</dt>
		1302	<dd>
		1303	<p>Make a single, non-blocking sweep over the embedded loop. This works
		1304	similarly to <code>ev_loop (embedded_loop, EVLOOP_NONBLOCK)</code>, but in the most
		1305	apropriate way for embedded loops.</p>
1126	</dd>	1306	</dd>
1127	</dl>	1307	</dl>
1128		1308
1129		1309
1130		1310
…		…
1163		1343
1164	ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0);	1344	ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0);
1165		1345
1166	</pre>	1346	</pre>
1167	</dd>	1347	</dd>
1168	<dt>ev_feed_event (loop, watcher, int events)</dt>	1348	<dt>ev_feed_event (ev_loop , watcher , int revents)</dt>
1169	<dd>	1349	<dd>
1170	<p>Feeds the given event set into the event loop, as if the specified event	1350	<p>Feeds the given event set into the event loop, as if the specified event
1171	had happened for the specified watcher (which must be a pointer to an	1351	had happened for the specified watcher (which must be a pointer to an
1172	initialised but not necessarily started event watcher).</p>	1352	initialised but not necessarily started event watcher).</p>
1173	</dd>	1353	</dd>
1174	<dt>ev_feed_fd_event (loop, int fd, int revents)</dt>	1354	<dt>ev_feed_fd_event (ev_loop *, int fd, int revents)</dt>
1175	<dd>	1355	<dd>
1176	<p>Feed an event on the given fd, as if a file descriptor backend detected	1356	<p>Feed an event on the given fd, as if a file descriptor backend detected
1177	the given events it.</p>	1357	the given events it.</p>
1178	</dd>	1358	</dd>
1179	<dt>ev_feed_signal_event (loop, int signum)</dt>	1359	<dt>ev_feed_signal_event (ev_loop *loop, int signum)</dt>
1180	<dd>	1360	<dd>
1181	<p>Feed an event as if the given signal occured (loop must be the default loop!).</p>	1361	<p>Feed an event as if the given signal occured (<code>loop</code> must be the default
		1362	loop!).</p>
1182	</dd>	1363	</dd>
1183	</dl>	1364	</dl>
1184		1365
1185		1366
1186		1367
…		…
1207	</dl>	1388	</dl>
1208		1389
1209	</div>	1390	</div>
1210	<h1 id="C_SUPPORT">C++ SUPPORT</h1><p><a href="#TOP" class="toplink">Top</a></p>	1391	<h1 id="C_SUPPORT">C++ SUPPORT</h1><p><a href="#TOP" class="toplink">Top</a></p>
1211	<div id="C_SUPPORT_CONTENT">	1392	<div id="C_SUPPORT_CONTENT">
1212	<p>TBD.</p>	1393	<p>Libev comes with some simplistic wrapper classes for C++ that mainly allow
		1394	you to use some convinience methods to start/stop watchers and also change
		1395	the callback model to a model using method callbacks on objects.</p>
		1396	<p>To use it,</p>
		1397	<pre> #include <ev++.h>
		1398
		1399	</pre>
		1400	<p>(it is not installed by default). This automatically includes <cite>ev.h</cite>
		1401	and puts all of its definitions (many of them macros) into the global
		1402	namespace. All C++ specific things are put into the <code>ev</code> namespace.</p>
		1403	<p>It should support all the same embedding options as <cite>ev.h</cite>, most notably
		1404	<code>EV_MULTIPLICITY</code>.</p>
		1405	<p>Here is a list of things available in the <code>ev</code> namespace:</p>
		1406	<dl>
		1407	<dt><code>ev::READ</code>, <code>ev::WRITE</code> etc.</dt>
		1408	<dd>
		1409	<p>These are just enum values with the same values as the <code>EV_READ</code> etc.
		1410	macros from <cite>ev.h</cite>.</p>
		1411	</dd>
		1412	<dt><code>ev::tstamp</code>, <code>ev::now</code></dt>
		1413	<dd>
		1414	<p>Aliases to the same types/functions as with the <code>ev_</code> prefix.</p>
		1415	</dd>
		1416	<dt><code>ev::io</code>, <code>ev::timer</code>, <code>ev::periodic</code>, <code>ev::idle</code>, <code>ev::sig</code> etc.</dt>
		1417	<dd>
		1418	<p>For each <code>ev_TYPE</code> watcher in <cite>ev.h</cite> there is a corresponding class of
		1419	the same name in the <code>ev</code> namespace, with the exception of <code>ev_signal</code>
		1420	which is called <code>ev::sig</code> to avoid clashes with the <code>signal</code> macro
		1421	defines by many implementations.</p>
		1422	<p>All of those classes have these methods:</p>
		1423	<p>
		1424	<dl>
		1425	<dt>ev::TYPE::TYPE (object , object::method )</dt>
		1426	<dt>ev::TYPE::TYPE (object , object::method , struct ev_loop *)</dt>
		1427	<dt>ev::TYPE::~TYPE</dt>
		1428	<dd>
		1429	<p>The constructor takes a pointer to an object and a method pointer to
		1430	the event handler callback to call in this class. The constructor calls
		1431	<code>ev_init</code> for you, which means you have to call the <code>set</code> method
		1432	before starting it. If you do not specify a loop then the constructor
		1433	automatically associates the default loop with this watcher.</p>
		1434	<p>The destructor automatically stops the watcher if it is active.</p>
		1435	</dd>
		1436	<dt>w->set (struct ev_loop *)</dt>
		1437	<dd>
		1438	<p>Associates a different <code>struct ev_loop</code> with this watcher. You can only
		1439	do this when the watcher is inactive (and not pending either).</p>
		1440	</dd>
		1441	<dt>w->set ([args])</dt>
		1442	<dd>
		1443	<p>Basically the same as <code>ev_TYPE_set</code>, with the same args. Must be
		1444	called at least once. Unlike the C counterpart, an active watcher gets
		1445	automatically stopped and restarted.</p>
		1446	</dd>
		1447	<dt>w->start ()</dt>
		1448	<dd>
		1449	<p>Starts the watcher. Note that there is no <code>loop</code> argument as the
		1450	constructor already takes the loop.</p>
		1451	</dd>
		1452	<dt>w->stop ()</dt>
		1453	<dd>
		1454	<p>Stops the watcher if it is active. Again, no <code>loop</code> argument.</p>
		1455	</dd>
		1456	<dt>w->again () <code>ev::timer</code>, <code>ev::periodic</code> only</dt>
		1457	<dd>
		1458	<p>For <code>ev::timer</code> and <code>ev::periodic</code>, this invokes the corresponding
		1459	<code>ev_TYPE_again</code> function.</p>
		1460	</dd>
		1461	<dt>w->sweep () <code>ev::embed</code> only</dt>
		1462	<dd>
		1463	<p>Invokes <code>ev_embed_sweep</code>.</p>
		1464	</dd>
		1465	</dl>
		1466	</p>
		1467	</dd>
		1468	</dl>
		1469	<p>Example: Define a class with an IO and idle watcher, start one of them in
		1470	the constructor.</p>
		1471	<pre> class myclass
		1472	{
		1473	ev_io io; void io_cb (ev::io &w, int revents);
		1474	ev_idle idle void idle_cb (ev::idle &w, int revents);
		1475
		1476	myclass ();
		1477	}
		1478
		1479	myclass::myclass (int fd)
		1480	: io (this, &myclass::io_cb),
		1481	idle (this, &myclass::idle_cb)
		1482	{
		1483	io.start (fd, ev::READ);
		1484	}
		1485
		1486	</pre>
		1487
		1488	</div>
		1489	<h1 id="EMBEDDING">EMBEDDING</h1><p><a href="#TOP" class="toplink">Top</a></p>
		1490	<div id="EMBEDDING_CONTENT">
		1491	<p>Libev can (and often is) directly embedded into host
		1492	applications. Examples of applications that embed it include the Deliantra
		1493	Game Server, the EV perl module, the GNU Virtual Private Ethernet (gvpe)
		1494	and rxvt-unicode.</p>
		1495	<p>The goal is to enable you to just copy the neecssary files into your
		1496	source directory without having to change even a single line in them, so
		1497	you can easily upgrade by simply copying (or having a checked-out copy of
		1498	libev somewhere in your source tree).</p>
		1499
		1500	</div>
		1501	<h2 id="FILESETS">FILESETS</h2>
		1502	<div id="FILESETS_CONTENT">
		1503	<p>Depending on what features you need you need to include one or more sets of files
		1504	in your app.</p>
		1505
		1506	</div>
		1507	<h3 id="CORE_EVENT_LOOP">CORE EVENT LOOP</h3>
		1508	<div id="CORE_EVENT_LOOP_CONTENT">
		1509	<p>To include only the libev core (all the <code>ev_*</code> functions), with manual
		1510	configuration (no autoconf):</p>
		1511	<pre> #define EV_STANDALONE 1
		1512	#include "ev.c"
		1513
		1514	</pre>
		1515	<p>This will automatically include <cite>ev.h</cite>, too, and should be done in a
		1516	single C source file only to provide the function implementations. To use
		1517	it, do the same for <cite>ev.h</cite> in all files wishing to use this API (best
		1518	done by writing a wrapper around <cite>ev.h</cite> that you can include instead and
		1519	where you can put other configuration options):</p>
		1520	<pre> #define EV_STANDALONE 1
		1521	#include "ev.h"
		1522
		1523	</pre>
		1524	<p>Both header files and implementation files can be compiled with a C++
		1525	compiler (at least, thats a stated goal, and breakage will be treated
		1526	as a bug).</p>
		1527	<p>You need the following files in your source tree, or in a directory
		1528	in your include path (e.g. in libev/ when using -Ilibev):</p>
		1529	<pre> ev.h
		1530	ev.c
		1531	ev_vars.h
		1532	ev_wrap.h
		1533
		1534	ev_win32.c required on win32 platforms only
		1535
		1536	ev_select.c only when select backend is enabled (which is by default)
		1537	ev_poll.c only when poll backend is enabled (disabled by default)
		1538	ev_epoll.c only when the epoll backend is enabled (disabled by default)
		1539	ev_kqueue.c only when the kqueue backend is enabled (disabled by default)
		1540	ev_port.c only when the solaris port backend is enabled (disabled by default)
		1541
		1542	</pre>
		1543	<p><cite>ev.c</cite> includes the backend files directly when enabled, so you only need
		1544	to compile this single file.</p>
		1545
		1546	</div>
		1547	<h3 id="LIBEVENT_COMPATIBILITY_API">LIBEVENT COMPATIBILITY API</h3>
		1548	<div id="LIBEVENT_COMPATIBILITY_API_CONTENT">
		1549	<p>To include the libevent compatibility API, also include:</p>
		1550	<pre> #include "event.c"
		1551
		1552	</pre>
		1553	<p>in the file including <cite>ev.c</cite>, and:</p>
		1554	<pre> #include "event.h"
		1555
		1556	</pre>
		1557	<p>in the files that want to use the libevent API. This also includes <cite>ev.h</cite>.</p>
		1558	<p>You need the following additional files for this:</p>
		1559	<pre> event.h
		1560	event.c
		1561
		1562	</pre>
		1563
		1564	</div>
		1565	<h3 id="AUTOCONF_SUPPORT">AUTOCONF SUPPORT</h3>
		1566	<div id="AUTOCONF_SUPPORT_CONTENT">
		1567	<p>Instead of using <code>EV_STANDALONE=1</code> and providing your config in
		1568	whatever way you want, you can also <code>m4_include([libev.m4])</code> in your
		1569	<cite>configure.ac</cite> and leave <code>EV_STANDALONE</code> undefined. <cite>ev.c</cite> will then
		1570	include <cite>config.h</cite> and configure itself accordingly.</p>
		1571	<p>For this of course you need the m4 file:</p>
		1572	<pre> libev.m4
		1573
		1574	</pre>
		1575
		1576	</div>
		1577	<h2 id="PREPROCESSOR_SYMBOLS_MACROS">PREPROCESSOR SYMBOLS/MACROS</h2>
		1578	<div id="PREPROCESSOR_SYMBOLS_MACROS_CONTENT">
		1579	<p>Libev can be configured via a variety of preprocessor symbols you have to define
		1580	before including any of its files. The default is not to build for multiplicity
		1581	and only include the select backend.</p>
		1582	<dl>
		1583	<dt>EV_STANDALONE</dt>
		1584	<dd>
		1585	<p>Must always be <code>1</code> if you do not use autoconf configuration, which
		1586	keeps libev from including <cite>config.h</cite>, and it also defines dummy
		1587	implementations for some libevent functions (such as logging, which is not
		1588	supported). It will also not define any of the structs usually found in
		1589	<cite>event.h</cite> that are not directly supported by the libev core alone.</p>
		1590	</dd>
		1591	<dt>EV_USE_MONOTONIC</dt>
		1592	<dd>
		1593	<p>If defined to be <code>1</code>, libev will try to detect the availability of the
		1594	monotonic clock option at both compiletime and runtime. Otherwise no use
		1595	of the monotonic clock option will be attempted. If you enable this, you
		1596	usually have to link against librt or something similar. Enabling it when
		1597	the functionality isn't available is safe, though, althoguh you have
		1598	to make sure you link against any libraries where the <code>clock_gettime</code>
		1599	function is hiding in (often <cite>-lrt</cite>).</p>
		1600	</dd>
		1601	<dt>EV_USE_REALTIME</dt>
		1602	<dd>
		1603	<p>If defined to be <code>1</code>, libev will try to detect the availability of the
		1604	realtime clock option at compiletime (and assume its availability at
		1605	runtime if successful). Otherwise no use of the realtime clock option will
		1606	be attempted. This effectively replaces <code>gettimeofday</code> by <code>clock_get
		1607	(CLOCK_REALTIME, ...)</code> and will not normally affect correctness. See tzhe note about libraries
		1608	in the description of <code>EV_USE_MONOTONIC</code>, though.</p>
		1609	</dd>
		1610	<dt>EV_USE_SELECT</dt>
		1611	<dd>
		1612	<p>If undefined or defined to be <code>1</code>, libev will compile in support for the
		1613	<code>select</code>(2) backend. No attempt at autodetection will be done: if no
		1614	other method takes over, select will be it. Otherwise the select backend
		1615	will not be compiled in.</p>
		1616	</dd>
		1617	<dt>EV_SELECT_USE_FD_SET</dt>
		1618	<dd>
		1619	<p>If defined to <code>1</code>, then the select backend will use the system <code>fd_set</code>
		1620	structure. This is useful if libev doesn't compile due to a missing
		1621	<code>NFDBITS</code> or <code>fd_mask</code> definition or it misguesses the bitset layout on
		1622	exotic systems. This usually limits the range of file descriptors to some
		1623	low limit such as 1024 or might have other limitations (winsocket only
		1624	allows 64 sockets). The <code>FD_SETSIZE</code> macro, set before compilation, might
		1625	influence the size of the <code>fd_set</code> used.</p>
		1626	</dd>
		1627	<dt>EV_SELECT_IS_WINSOCKET</dt>
		1628	<dd>
		1629	<p>When defined to <code>1</code>, the select backend will assume that
		1630	select/socket/connect etc. don't understand file descriptors but
		1631	wants osf handles on win32 (this is the case when the select to
		1632	be used is the winsock select). This means that it will call
		1633	<code>_get_osfhandle</code> on the fd to convert it to an OS handle. Otherwise,
		1634	it is assumed that all these functions actually work on fds, even
		1635	on win32. Should not be defined on non-win32 platforms.</p>
		1636	</dd>
		1637	<dt>EV_USE_POLL</dt>
		1638	<dd>
		1639	<p>If defined to be <code>1</code>, libev will compile in support for the <code>poll</code>(2)
		1640	backend. Otherwise it will be enabled on non-win32 platforms. It
		1641	takes precedence over select.</p>
		1642	</dd>
		1643	<dt>EV_USE_EPOLL</dt>
		1644	<dd>
		1645	<p>If defined to be <code>1</code>, libev will compile in support for the Linux
		1646	<code>epoll</code>(7) backend. Its availability will be detected at runtime,
		1647	otherwise another method will be used as fallback. This is the
		1648	preferred backend for GNU/Linux systems.</p>
		1649	</dd>
		1650	<dt>EV_USE_KQUEUE</dt>
		1651	<dd>
		1652	<p>If defined to be <code>1</code>, libev will compile in support for the BSD style
		1653	<code>kqueue</code>(2) backend. Its actual availability will be detected at runtime,
		1654	otherwise another method will be used as fallback. This is the preferred
		1655	backend for BSD and BSD-like systems, although on most BSDs kqueue only
		1656	supports some types of fds correctly (the only platform we found that
		1657	supports ptys for example was NetBSD), so kqueue might be compiled in, but
		1658	not be used unless explicitly requested. The best way to use it is to find
		1659	out whether kqueue supports your type of fd properly and use an embedded
		1660	kqueue loop.</p>
		1661	</dd>
		1662	<dt>EV_USE_PORT</dt>
		1663	<dd>
		1664	<p>If defined to be <code>1</code>, libev will compile in support for the Solaris
		1665	10 port style backend. Its availability will be detected at runtime,
		1666	otherwise another method will be used as fallback. This is the preferred
		1667	backend for Solaris 10 systems.</p>
		1668	</dd>
		1669	<dt>EV_USE_DEVPOLL</dt>
		1670	<dd>
		1671	<p>reserved for future expansion, works like the USE symbols above.</p>
		1672	</dd>
		1673	<dt>EV_H</dt>
		1674	<dd>
		1675	<p>The name of the <cite>ev.h</cite> header file used to include it. The default if
		1676	undefined is <code><ev.h></code> in <cite>event.h</cite> and <code>"ev.h"</code> in <cite>ev.c</cite>. This
		1677	can be used to virtually rename the <cite>ev.h</cite> header file in case of conflicts.</p>
		1678	</dd>
		1679	<dt>EV_CONFIG_H</dt>
		1680	<dd>
		1681	<p>If <code>EV_STANDALONE</code> isn't <code>1</code>, this variable can be used to override
		1682	<cite>ev.c</cite>'s idea of where to find the <cite>config.h</cite> file, similarly to
		1683	<code>EV_H</code>, above.</p>
		1684	</dd>
		1685	<dt>EV_EVENT_H</dt>
		1686	<dd>
		1687	<p>Similarly to <code>EV_H</code>, this macro can be used to override <cite>event.c</cite>'s idea
		1688	of how the <cite>event.h</cite> header can be found.</p>
		1689	</dd>
		1690	<dt>EV_PROTOTYPES</dt>
		1691	<dd>
		1692	<p>If defined to be <code>0</code>, then <cite>ev.h</cite> will not define any function
		1693	prototypes, but still define all the structs and other symbols. This is
		1694	occasionally useful if you want to provide your own wrapper functions
		1695	around libev functions.</p>
		1696	</dd>
		1697	<dt>EV_MULTIPLICITY</dt>
		1698	<dd>
		1699	<p>If undefined or defined to <code>1</code>, then all event-loop-specific functions
		1700	will have the <code>struct ev_loop *</code> as first argument, and you can create
		1701	additional independent event loops. Otherwise there will be no support
		1702	for multiple event loops and there is no first event loop pointer
		1703	argument. Instead, all functions act on the single default loop.</p>
		1704	</dd>
		1705	<dt>EV_PERIODICS</dt>
		1706	<dd>
		1707	<p>If undefined or defined to be <code>1</code>, then periodic timers are supported,
		1708	otherwise not. This saves a few kb of code.</p>
		1709	</dd>
		1710	<dt>EV_COMMON</dt>
		1711	<dd>
		1712	<p>By default, all watchers have a <code>void *data</code> member. By redefining
		1713	this macro to a something else you can include more and other types of
		1714	members. You have to define it each time you include one of the files,
		1715	though, and it must be identical each time.</p>
		1716	<p>For example, the perl EV module uses something like this:</p>
		1717	<pre> #define EV_COMMON \
		1718	SV self; / contains this struct */ \
		1719	SV cb_sv, fh /* note no trailing ";" */
		1720
		1721	</pre>
		1722	</dd>
		1723	<dt>EV_CB_DECLARE (type)</dt>
		1724	<dt>EV_CB_INVOKE (watcher, revents)</dt>
		1725	<dt>ev_set_cb (ev, cb)</dt>
		1726	<dd>
		1727	<p>Can be used to change the callback member declaration in each watcher,
		1728	and the way callbacks are invoked and set. Must expand to a struct member
		1729	definition and a statement, respectively. See the <cite>ev.v</cite> header file for
		1730	their default definitions. One possible use for overriding these is to
		1731	avoid the <code>struct ev_loop *</code> as first argument in all cases, or to use
		1732	method calls instead of plain function calls in C++.</p>
		1733
		1734	</div>
		1735	<h2 id="EXAMPLES">EXAMPLES</h2>
		1736	<div id="EXAMPLES_CONTENT">
		1737	<p>For a real-world example of a program the includes libev
		1738	verbatim, you can have a look at the EV perl module
		1739	(<a href="http://software.schmorp.de/pkg/EV.html">http://software.schmorp.de/pkg/EV.html</a>). It has the libev files in
		1740	the <cite>libev/</cite> subdirectory and includes them in the <cite>EV/EVAPI.h</cite> (public
		1741	interface) and <cite>EV.xs</cite> (implementation) files. Only the <cite>EV.xs</cite> file
		1742	will be compiled. It is pretty complex because it provides its own header
		1743	file.</p>
		1744	<p>The usage in rxvt-unicode is simpler. It has a <cite>ev_cpp.h</cite> header file
		1745	that everybody includes and which overrides some autoconf choices:</p>
		1746	<pre> #define EV_USE_POLL 0
		1747	#define EV_MULTIPLICITY 0
		1748	#define EV_PERIODICS 0
		1749	#define EV_CONFIG_H <config.h>
		1750
		1751	#include "ev++.h"
		1752
		1753	</pre>
		1754	<p>And a <cite>ev_cpp.C</cite> implementation file that contains libev proper and is compiled:</p>
		1755	<pre> #include "ev_cpp.h"
		1756	#include "ev.c"
		1757
		1758	</pre>
1213		1759
1214	</div>	1760	</div>
1215	<h1 id="AUTHOR">AUTHOR</h1><p><a href="#TOP" class="toplink">Top</a></p>	1761	<h1 id="AUTHOR">AUTHOR</h1><p><a href="#TOP" class="toplink">Top</a></p>
1216	<div id="AUTHOR_CONTENT">	1762	<div id="AUTHOR_CONTENT">
1217	<p>Marc Lehmann <libev@schmorp.de>.</p>	1763	<p>Marc Lehmann <libev@schmorp.de>.</p>
1218		1764
1219	</div>	1765	</div>
1220	</div></body>	1766	</div></body>
1221	</html>	1767	</html>

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Revision 1.46 by root, Mon Nov 26 09:52:14 2007 UTC