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Revision 1.58 by root, Wed Nov 28 11:31:34 2007 UTC

…		…
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>" />
8	<meta name="outputfile" content="<standard output>" />	8	<meta name="outputfile" content="<standard output>" />
9	<meta name="created" content="Sat Nov 24 08:13:46 2007" />	9	<meta name="created" content="Wed Nov 28 12:31:29 2007" />
10	<meta name="generator" content="Pod::Xhtml 1.57" />	10	<meta name="generator" content="Pod::Xhtml 1.57" />
11	<link rel="stylesheet" href="http://res.tst.eu/pod.css"/></head>	11	<link rel="stylesheet" href="http://res.tst.eu/pod.css"/></head>
12	<body>	12	<body>
13	<div class="pod">	13	<div class="pod">
14	<!-- INDEX START -->	14	<!-- INDEX START -->
15	<h3 id="TOP">Index</h3>	15	<h3 id="TOP">Index</h3>
16		16
17	<ul><li><a href="#NAME">NAME</a></li>	17	<ul><li><a href="#NAME">NAME</a></li>
18	<li><a href="#SYNOPSIS">SYNOPSIS</a></li>	18	<li><a href="#SYNOPSIS">SYNOPSIS</a></li>
		19	<li><a href="#EXAMPLE_PROGRAM">EXAMPLE PROGRAM</a></li>
19	<li><a href="#DESCRIPTION">DESCRIPTION</a></li>	20	<li><a href="#DESCRIPTION">DESCRIPTION</a></li>
20	<li><a href="#FEATURES">FEATURES</a></li>	21	<li><a href="#FEATURES">FEATURES</a></li>
21	<li><a href="#CONVENTIONS">CONVENTIONS</a></li>	22	<li><a href="#CONVENTIONS">CONVENTIONS</a></li>
22	<li><a href="#TIME_REPRESENTATION">TIME REPRESENTATION</a></li>	23	<li><a href="#TIME_REPRESENTATION">TIME REPRESENTATION</a></li>
23	<li><a href="#GLOBAL_FUNCTIONS">GLOBAL FUNCTIONS</a></li>	24	<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>	25	<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>	26	<li><a href="#ANATOMY_OF_A_WATCHER">ANATOMY OF A WATCHER</a>
26	<ul><li><a href="#SUMMARY_OF_GENERIC_WATCHER_FUNCTIONS">SUMMARY OF GENERIC WATCHER FUNCTIONS</a></li>	27	<ul><li><a href="#GENERIC_WATCHER_FUNCTIONS">GENERIC WATCHER FUNCTIONS</a></li>
27	<li><a href="#ASSOCIATING_CUSTOM_DATA_WITH_A_WATCH">ASSOCIATING CUSTOM DATA WITH A WATCHER</a></li>	28	<li><a href="#ASSOCIATING_CUSTOM_DATA_WITH_A_WATCH">ASSOCIATING CUSTOM DATA WITH A WATCHER</a></li>
28	</ul>	29	</ul>
29	</li>	30	</li>
30	<li><a href="#WATCHER_TYPES">WATCHER TYPES</a>	31	<li><a href="#WATCHER_TYPES">WATCHER TYPES</a>
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>	32	<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>
32	<li><a href="#code_ev_timer_code_relative_and_opti"><code>ev_timer</code> - relative and optionally recurring timeouts</a></li>	33	<li><a href="#code_ev_timer_code_relative_and_opti"><code>ev_timer</code> - relative and optionally repeating timeouts</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>	34	<li><a href="#code_ev_periodic_code_to_cron_or_not"><code>ev_periodic</code> - to cron or not to cron?</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>	35	<li><a href="#code_ev_signal_code_signal_me_when_a"><code>ev_signal</code> - signal me when a signal gets signalled!</a></li>
35	<li><a href="#code_ev_child_code_wait_for_pid_stat"><code>ev_child</code> - wait for pid status changes</a></li>	36	<li><a href="#code_ev_child_code_watch_out_for_pro"><code>ev_child</code> - watch out for process status changes</a></li>
		37	<li><a href="#code_ev_stat_code_did_the_file_attri"><code>ev_stat</code> - did the file attributes just change?</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>	38	<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>
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>	39	<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>
38	<li><a href="#code_ev_embed_code_when_one_backend_"><code>ev_embed</code> - when one backend isn't enough</a></li>	40	<li><a href="#code_ev_embed_code_when_one_backend_"><code>ev_embed</code> - when one backend isn't enough...</a></li>
		41	<li><a href="#code_ev_fork_code_the_audacity_to_re"><code>ev_fork</code> - the audacity to resume the event loop after a fork</a></li>
39	</ul>	42	</ul>
40	</li>	43	</li>
41	<li><a href="#OTHER_FUNCTIONS">OTHER FUNCTIONS</a></li>	44	<li><a href="#OTHER_FUNCTIONS">OTHER FUNCTIONS</a></li>
42	<li><a href="#LIBEVENT_EMULATION">LIBEVENT EMULATION</a></li>	45	<li><a href="#LIBEVENT_EMULATION">LIBEVENT EMULATION</a></li>
43	<li><a href="#C_SUPPORT">C++ SUPPORT</a></li>	46	<li><a href="#C_SUPPORT">C++ SUPPORT</a></li>
		47	<li><a href="#MACRO_MAGIC">MACRO MAGIC</a></li>
		48	<li><a href="#EMBEDDING">EMBEDDING</a>
		49	<ul><li><a href="#FILESETS">FILESETS</a>
		50	<ul><li><a href="#CORE_EVENT_LOOP">CORE EVENT LOOP</a></li>
		51	<li><a href="#LIBEVENT_COMPATIBILITY_API">LIBEVENT COMPATIBILITY API</a></li>
		52	<li><a href="#AUTOCONF_SUPPORT">AUTOCONF SUPPORT</a></li>
		53	</ul>
		54	</li>
		55	<li><a href="#PREPROCESSOR_SYMBOLS_MACROS">PREPROCESSOR SYMBOLS/MACROS</a></li>
		56	<li><a href="#EXAMPLES">EXAMPLES</a></li>
		57	</ul>
		58	</li>
		59	<li><a href="#COMPLEXITIES">COMPLEXITIES</a></li>
44	<li><a href="#AUTHOR">AUTHOR</a>	60	<li><a href="#AUTHOR">AUTHOR</a>
45	</li>	61	</li>
46	</ul><hr />	62	</ul><hr />
47	<!-- INDEX END -->	63	<!-- INDEX END -->
48		64
49	<h1 id="NAME">NAME</h1><p><a href="#TOP" class="toplink">Top</a></p>	65	<h1 id="NAME">NAME</h1>
50	<div id="NAME_CONTENT">	66	<div id="NAME_CONTENT">
51	<p>libev - a high performance full-featured event loop written in C</p>	67	<p>libev - a high performance full-featured event loop written in C</p>
52		68
53	</div>	69	</div>
54	<h1 id="SYNOPSIS">SYNOPSIS</h1><p><a href="#TOP" class="toplink">Top</a></p>	70	<h1 id="SYNOPSIS">SYNOPSIS</h1>
55	<div id="SYNOPSIS_CONTENT">	71	<div id="SYNOPSIS_CONTENT">
56	<pre> #include <ev.h>	72	<pre> #include <ev.h>
57		73
58	</pre>	74	</pre>
59		75
60	</div>	76	</div>
61	<h1 id="DESCRIPTION">DESCRIPTION</h1><p><a href="#TOP" class="toplink">Top</a></p>	77	<h1 id="EXAMPLE_PROGRAM">EXAMPLE PROGRAM</h1>
		78	<div id="EXAMPLE_PROGRAM_CONTENT">
		79	<pre> #include <ev.h>
		80
		81	ev_io stdin_watcher;
		82	ev_timer timeout_watcher;
		83
		84	/* called when data readable on stdin */
		85	static void
		86	stdin_cb (EV_P_ struct ev_io *w, int revents)
		87	{
		88	/* puts ("stdin ready"); */
		89	ev_io_stop (EV_A_ w); /* just a syntax example */
		90	ev_unloop (EV_A_ EVUNLOOP_ALL); /* leave all loop calls */
		91	}
		92
		93	static void
		94	timeout_cb (EV_P_ struct ev_timer *w, int revents)
		95	{
		96	/* puts ("timeout"); */
		97	ev_unloop (EV_A_ EVUNLOOP_ONE); /* leave one loop call */
		98	}
		99
		100	int
		101	main (void)
		102	{
		103	struct ev_loop *loop = ev_default_loop (0);
		104
		105	/* initialise an io watcher, then start it */
		106	ev_io_init (&stdin_watcher, stdin_cb, /STDIN_FILENO/ 0, EV_READ);
		107	ev_io_start (loop, &stdin_watcher);
		108
		109	/* simple non-repeating 5.5 second timeout */
		110	ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.);
		111	ev_timer_start (loop, &timeout_watcher);
		112
		113	/* loop till timeout or data ready */
		114	ev_loop (loop, 0);
		115
		116	return 0;
		117	}
		118
		119	</pre>
		120
		121	</div>
		122	<h1 id="DESCRIPTION">DESCRIPTION</h1>
62	<div id="DESCRIPTION_CONTENT">	123	<div id="DESCRIPTION_CONTENT">
63	<p>Libev is an event loop: you register interest in certain events (such as a	124	<p>Libev is an event loop: you register interest in certain events (such as a
64	file descriptor being readable or a timeout occuring), and it will manage	125	file descriptor being readable or a timeout occuring), and it will manage
65	these event sources and provide your program with events.</p>	126	these event sources and provide your program with events.</p>
66	<p>To do this, it must take more or less complete control over your process	127	<p>To do this, it must take more or less complete control over your process
…		…
70	watchers</i>, which are relatively small C structures you initialise with the	131	watchers</i>, which are relatively small C structures you initialise with the
71	details of the event, and then hand it over to libev by <i>starting</i> the	132	details of the event, and then hand it over to libev by <i>starting</i> the
72	watcher.</p>	133	watcher.</p>
73		134
74	</div>	135	</div>
75	<h1 id="FEATURES">FEATURES</h1><p><a href="#TOP" class="toplink">Top</a></p>	136	<h1 id="FEATURES">FEATURES</h1>
76	<div id="FEATURES_CONTENT">	137	<div id="FEATURES_CONTENT">
77	<p>Libev supports select, poll, the linux-specific epoll and the bsd-specific	138	<p>Libev supports <code>select</code>, <code>poll</code>, the Linux-specific <code>epoll</code>, the
78	kqueue mechanisms for file descriptor events, relative timers, absolute	139	BSD-specific <code>kqueue</code> and the Solaris-specific event port mechanisms
79	timers with customised rescheduling, signal events, process status change	140	for file descriptor events (<code>ev_io</code>), the Linux <code>inotify</code> interface
80	events (related to SIGCHLD), and event watchers dealing with the event	141	(for <code>ev_stat</code>), relative timers (<code>ev_timer</code>), absolute timers
81	loop mechanism itself (idle, prepare and check watchers). It also is quite	142	with customised rescheduling (<code>ev_periodic</code>), synchronous signals
		143	(<code>ev_signal</code>), process status change events (<code>ev_child</code>), and event
		144	watchers dealing with the event loop mechanism itself (<code>ev_idle</code>,
		145	<code>ev_embed</code>, <code>ev_prepare</code> and <code>ev_check</code> watchers) as well as
		146	file watchers (<code>ev_stat</code>) and even limited support for fork events
		147	(<code>ev_fork</code>).</p>
		148	<p>It also is quite fast (see this
82	fast (see this <a href="http://libev.schmorp.de/bench.html">benchmark</a> comparing	149	<a href="http://libev.schmorp.de/bench.html">benchmark</a> comparing it to libevent
83	it to libevent for example).</p>	150	for example).</p>
84		151
85	</div>	152	</div>
86	<h1 id="CONVENTIONS">CONVENTIONS</h1><p><a href="#TOP" class="toplink">Top</a></p>	153	<h1 id="CONVENTIONS">CONVENTIONS</h1>
87	<div id="CONVENTIONS_CONTENT">	154	<div id="CONVENTIONS_CONTENT">
88	<p>Libev is very configurable. In this manual the default configuration	155	<p>Libev is very configurable. In this manual the default configuration will
89	will be described, which supports multiple event loops. For more info	156	be described, which supports multiple event loops. For more info about
90	about various configuration options please have a look at the file	157	various configuration options please have a look at <strong>EMBED</strong> section in
91	<cite>README.embed</cite> in the libev distribution. If libev was configured without	158	this manual. If libev was configured without support for multiple event
92	support for multiple event loops, then all functions taking an initial	159	loops, then all functions taking an initial argument of name <code>loop</code>
93	argument of name <code>loop</code> (which is always of type <code>struct ev_loop *</code>)	160	(which is always of type <code>struct ev_loop *</code>) will not have this argument.</p>
94	will not have this argument.</p>
95		161
96	</div>	162	</div>
97	<h1 id="TIME_REPRESENTATION">TIME REPRESENTATION</h1><p><a href="#TOP" class="toplink">Top</a></p>	163	<h1 id="TIME_REPRESENTATION">TIME REPRESENTATION</h1>
98	<div id="TIME_REPRESENTATION_CONTENT">	164	<div id="TIME_REPRESENTATION_CONTENT">
99	<p>Libev represents time as a single floating point number, representing the	165	<p>Libev represents time as a single floating point number, representing the
100	(fractional) number of seconds since the (POSIX) epoch (somewhere near	166	(fractional) number of seconds since the (POSIX) epoch (somewhere near
101	the beginning of 1970, details are complicated, don't ask). This type is	167	the beginning of 1970, details are complicated, don't ask). This type is
102	called <code>ev_tstamp</code>, which is what you should use too. It usually aliases	168	called <code>ev_tstamp</code>, which is what you should use too. It usually aliases
103	to the <code>double</code> type in C, and when you need to do any calculations on	169	to the <code>double</code> type in C, and when you need to do any calculations on
104	it, you should treat it as such.</p>	170	it, you should treat it as such.</p>
105		171
106
107
108
109
110	</div>	172	</div>
111	<h1 id="GLOBAL_FUNCTIONS">GLOBAL FUNCTIONS</h1><p><a href="#TOP" class="toplink">Top</a></p>	173	<h1 id="GLOBAL_FUNCTIONS">GLOBAL FUNCTIONS</h1>
112	<div id="GLOBAL_FUNCTIONS_CONTENT">	174	<div id="GLOBAL_FUNCTIONS_CONTENT">
113	<p>These functions can be called anytime, even before initialising the	175	<p>These functions can be called anytime, even before initialising the
114	library in any way.</p>	176	library in any way.</p>
115	<dl>	177	<dl>
116	<dt>ev_tstamp ev_time ()</dt>	178	<dt>ev_tstamp ev_time ()</dt>
…		…
129	version of the library your program was compiled against.</p>	191	version of the library your program was compiled against.</p>
130	<p>Usually, it's a good idea to terminate if the major versions mismatch,	192	<p>Usually, it's a good idea to terminate if the major versions mismatch,
131	as this indicates an incompatible change. Minor versions are usually	193	as this indicates an incompatible change. Minor versions are usually
132	compatible to older versions, so a larger minor version alone is usually	194	compatible to older versions, so a larger minor version alone is usually
133	not a problem.</p>	195	not a problem.</p>
134	<p>Example: make sure we haven't accidentally been linked against the wrong	196	<p>Example: Make sure we haven't accidentally been linked against the wrong
135	version:</p>	197	version.</p>
136	<pre> assert (("libev version mismatch",	198	<pre> assert (("libev version mismatch",
137	ev_version_major () == EV_VERSION_MAJOR	199	ev_version_major () == EV_VERSION_MAJOR
138	&& ev_version_minor () >= EV_VERSION_MINOR));	200	&& ev_version_minor () >= EV_VERSION_MINOR));
139		201
140	</pre>	202	</pre>
…		…
168	might be supported on the current system, you would need to look at	230	might be supported on the current system, you would need to look at
169	<code>ev_embeddable_backends () & ev_supported_backends ()</code>, likewise for	231	<code>ev_embeddable_backends () & ev_supported_backends ()</code>, likewise for
170	recommended ones.</p>	232	recommended ones.</p>
171	<p>See the description of <code>ev_embed</code> watchers for more info.</p>	233	<p>See the description of <code>ev_embed</code> watchers for more info.</p>
172	</dd>	234	</dd>
173	<dt>ev_set_allocator (void (cb)(void *ptr, long size))</dt>	235	<dt>ev_set_allocator (void (cb)(void *ptr, size_t size))</dt>
174	<dd>	236	<dd>
175	<p>Sets the allocation function to use (the prototype is similar to the	237	<p>Sets the allocation function to use (the prototype and semantics are
176	realloc C function, the semantics are identical). It is used to allocate	238	identical to the realloc C function). It is used to allocate and free
177	and free memory (no surprises here). If it returns zero when memory	239	memory (no surprises here). If it returns zero when memory needs to be
178	needs to be allocated, the library might abort or take some potentially	240	allocated, the library might abort or take some potentially destructive
179	destructive action. The default is your system realloc function.</p>	241	action. The default is your system realloc function.</p>
180	<p>You could override this function in high-availability programs to, say,	242	<p>You could override this function in high-availability programs to, say,
181	free some memory if it cannot allocate memory, to use a special allocator,	243	free some memory if it cannot allocate memory, to use a special allocator,
182	or even to sleep a while and retry until some memory is available.</p>	244	or even to sleep a while and retry until some memory is available.</p>
183	<p>Example: replace the libev allocator with one that waits a bit and then	245	<p>Example: Replace the libev allocator with one that waits a bit and then
184	retries: better than mine).</p>	246	retries).</p>
185	<pre> static void *	247	<pre> static void *
186	persistent_realloc (void *ptr, long size)	248	persistent_realloc (void *ptr, size_t size)
187	{	249	{
188	for (;;)	250	for (;;)
189	{	251	{
190	void *newptr = realloc (ptr, size);	252	void *newptr = realloc (ptr, size);
191		253
…		…
208	indicating the system call or subsystem causing the problem. If this	270	indicating the system call or subsystem causing the problem. If this
209	callback is set, then libev will expect it to remedy the sitution, no	271	callback is set, then libev will expect it to remedy the sitution, no
210	matter what, when it returns. That is, libev will generally retry the	272	matter what, when it returns. That is, libev will generally retry the
211	requested operation, or, if the condition doesn't go away, do bad stuff	273	requested operation, or, if the condition doesn't go away, do bad stuff
212	(such as abort).</p>	274	(such as abort).</p>
213	<p>Example: do the same thing as libev does internally:</p>	275	<p>Example: This is basically the same thing that libev does internally, too.</p>
214	<pre> static void	276	<pre> static void
215	fatal_error (const char *msg)	277	fatal_error (const char *msg)
216	{	278	{
217	perror (msg);	279	perror (msg);
218	abort ();	280	abort ();
…		…
224	</pre>	286	</pre>
225	</dd>	287	</dd>
226	</dl>	288	</dl>
227		289
228	</div>	290	</div>
229	<h1 id="FUNCTIONS_CONTROLLING_THE_EVENT_LOOP">FUNCTIONS CONTROLLING THE EVENT LOOP</h1><p><a href="#TOP" class="toplink">Top</a></p>	291	<h1 id="FUNCTIONS_CONTROLLING_THE_EVENT_LOOP">FUNCTIONS CONTROLLING THE EVENT LOOP</h1>
230	<div id="FUNCTIONS_CONTROLLING_THE_EVENT_LOOP-2">	292	<div id="FUNCTIONS_CONTROLLING_THE_EVENT_LOOP-2">
231	<p>An event loop is described by a <code>struct ev_loop *</code>. The library knows two	293	<p>An event loop is described by a <code>struct ev_loop *</code>. The library knows two
232	types of such loops, the <i>default</i> loop, which supports signals and child	294	types of such loops, the <i>default</i> loop, which supports signals and child
233	events, and dynamically created loops which do not.</p>	295	events, and dynamically created loops which do not.</p>
234	<p>If you use threads, a common model is to run the default event loop	296	<p>If you use threads, a common model is to run the default event loop
…		…
354	<dd>	416	<dd>
355	<p>Similar to <code>ev_default_loop</code>, but always creates a new event loop that is	417	<p>Similar to <code>ev_default_loop</code>, but always creates a new event loop that is
356	always distinct from the default loop. Unlike the default loop, it cannot	418	always distinct from the default loop. Unlike the default loop, it cannot
357	handle signal and child watchers, and attempts to do so will be greeted by	419	handle signal and child watchers, and attempts to do so will be greeted by
358	undefined behaviour (or a failed assertion if assertions are enabled).</p>	420	undefined behaviour (or a failed assertion if assertions are enabled).</p>
359	<p>Example: try to create a event loop that uses epoll and nothing else.</p>	421	<p>Example: Try to create a event loop that uses epoll and nothing else.</p>
360	<pre> struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL \| EVFLAG_NOENV);	422	<pre> struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL \| EVFLAG_NOENV);
361	if (!epoller)	423	if (!epoller)
362	fatal ("no epoll found here, maybe it hides under your chair");	424	fatal ("no epoll found here, maybe it hides under your chair");
363		425
364	</pre>	426	</pre>
365	</dd>	427	</dd>
366	<dt>ev_default_destroy ()</dt>	428	<dt>ev_default_destroy ()</dt>
367	<dd>	429	<dd>
368	<p>Destroys the default loop again (frees all memory and kernel state	430	<p>Destroys the default loop again (frees all memory and kernel state
369	etc.). This stops all registered event watchers (by not touching them in	431	etc.). None of the active event watchers will be stopped in the normal
370	any way whatsoever, although you cannot rely on this :).</p>	432	sense, so e.g. <code>ev_is_active</code> might still return true. It is your
		433	responsibility to either stop all watchers cleanly yoursef <i>before</i>
		434	calling this function, or cope with the fact afterwards (which is usually
		435	the easiest thing, youc na just ignore the watchers and/or <code>free ()</code> them
		436	for example).</p>
371	</dd>	437	</dd>
372	<dt>ev_loop_destroy (loop)</dt>	438	<dt>ev_loop_destroy (loop)</dt>
373	<dd>	439	<dd>
374	<p>Like <code>ev_default_destroy</code>, but destroys an event loop created by an	440	<p>Like <code>ev_default_destroy</code>, but destroys an event loop created by an
375	earlier call to <code>ev_loop_new</code>.</p>	441	earlier call to <code>ev_loop_new</code>.</p>
…		…
453	be handled here by queueing them when their watcher gets executed.	519	be handled here by queueing them when their watcher gets executed.
454	- If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK	520	- If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK
455	were used, return, otherwise continue with step *.	521	were used, return, otherwise continue with step *.
456		522
457	</pre>	523	</pre>
458	<p>Example: queue some jobs and then loop until no events are outsanding	524	<p>Example: Queue some jobs and then loop until no events are outsanding
459	anymore.</p>	525	anymore.</p>
460	<pre> ... queue jobs here, make sure they register event watchers as long	526	<pre> ... queue jobs here, make sure they register event watchers as long
461	... as they still have work to do (even an idle watcher will do..)	527	... as they still have work to do (even an idle watcher will do..)
462	ev_loop (my_loop, 0);	528	ev_loop (my_loop, 0);
463	... jobs done. yeah!	529	... jobs done. yeah!
…		…
482	example, libev itself uses this for its internal signal pipe: It is not	548	example, libev itself uses this for its internal signal pipe: It is not
483	visible to the libev user and should not keep <code>ev_loop</code> from exiting if	549	visible to the libev user and should not keep <code>ev_loop</code> from exiting if
484	no event watchers registered by it are active. It is also an excellent	550	no event watchers registered by it are active. It is also an excellent
485	way to do this for generic recurring timers or from within third-party	551	way to do this for generic recurring timers or from within third-party
486	libraries. Just remember to <i>unref after start</i> and <i>ref before stop</i>.</p>	552	libraries. Just remember to <i>unref after start</i> and <i>ref before stop</i>.</p>
487	<p>Example: create a signal watcher, but keep it from keeping <code>ev_loop</code>	553	<p>Example: Create a signal watcher, but keep it from keeping <code>ev_loop</code>
488	running when nothing else is active.</p>	554	running when nothing else is active.</p>
489	<pre> struct dv_signal exitsig;	555	<pre> struct ev_signal exitsig;
490	ev_signal_init (&exitsig, sig_cb, SIGINT);	556	ev_signal_init (&exitsig, sig_cb, SIGINT);
491	ev_signal_start (myloop, &exitsig);	557	ev_signal_start (loop, &exitsig);
492	evf_unref (myloop);	558	evf_unref (loop);
493		559
494	</pre>	560	</pre>
495	<p>Example: for some weird reason, unregister the above signal handler again.</p>	561	<p>Example: For some weird reason, unregister the above signal handler again.</p>
496	<pre> ev_ref (myloop);	562	<pre> ev_ref (loop);
497	ev_signal_stop (myloop, &exitsig);	563	ev_signal_stop (loop, &exitsig);
498		564
499	</pre>	565	</pre>
500	</dd>	566	</dd>
501	</dl>	567	</dl>
502		568
		569
		570
		571
		572
503	</div>	573	</div>
504	<h1 id="ANATOMY_OF_A_WATCHER">ANATOMY OF A WATCHER</h1><p><a href="#TOP" class="toplink">Top</a></p>	574	<h1 id="ANATOMY_OF_A_WATCHER">ANATOMY OF A WATCHER</h1>
505	<div id="ANATOMY_OF_A_WATCHER_CONTENT">	575	<div id="ANATOMY_OF_A_WATCHER_CONTENT">
506	<p>A watcher is a structure that you create and register to record your	576	<p>A watcher is a structure that you create and register to record your
507	interest in some event. For instance, if you want to wait for STDIN to	577	interest in some event. For instance, if you want to wait for STDIN to
508	become readable, you would create an <code>ev_io</code> watcher for that:</p>	578	become readable, you would create an <code>ev_io</code> watcher for that:</p>
509	<pre> static void my_cb (struct ev_loop loop, struct ev_io w, int revents)	579	<pre> static void my_cb (struct ev_loop loop, struct ev_io w, int revents)
…		…
566	</dd>	636	</dd>
567	<dt><code>EV_CHILD</code></dt>	637	<dt><code>EV_CHILD</code></dt>
568	<dd>	638	<dd>
569	<p>The pid specified in the <code>ev_child</code> watcher has received a status change.</p>	639	<p>The pid specified in the <code>ev_child</code> watcher has received a status change.</p>
570	</dd>	640	</dd>
		641	<dt><code>EV_STAT</code></dt>
		642	<dd>
		643	<p>The path specified in the <code>ev_stat</code> watcher changed its attributes somehow.</p>
		644	</dd>
571	<dt><code>EV_IDLE</code></dt>	645	<dt><code>EV_IDLE</code></dt>
572	<dd>	646	<dd>
573	<p>The <code>ev_idle</code> watcher has determined that you have nothing better to do.</p>	647	<p>The <code>ev_idle</code> watcher has determined that you have nothing better to do.</p>
574	</dd>	648	</dd>
575	<dt><code>EV_PREPARE</code></dt>	649	<dt><code>EV_PREPARE</code></dt>
…		…
580	<code>ev_loop</code> has gathered them, but before it invokes any callbacks for any	654	<code>ev_loop</code> has gathered them, but before it invokes any callbacks for any
581	received events. Callbacks of both watcher types can start and stop as	655	received events. Callbacks of both watcher types can start and stop as
582	many watchers as they want, and all of them will be taken into account	656	many watchers as they want, and all of them will be taken into account
583	(for example, a <code>ev_prepare</code> watcher might start an idle watcher to keep	657	(for example, a <code>ev_prepare</code> watcher might start an idle watcher to keep
584	<code>ev_loop</code> from blocking).</p>	658	<code>ev_loop</code> from blocking).</p>
		659	</dd>
		660	<dt><code>EV_EMBED</code></dt>
		661	<dd>
		662	<p>The embedded event loop specified in the <code>ev_embed</code> watcher needs attention.</p>
		663	</dd>
		664	<dt><code>EV_FORK</code></dt>
		665	<dd>
		666	<p>The event loop has been resumed in the child process after fork (see
		667	<code>ev_fork</code>).</p>
585	</dd>	668	</dd>
586	<dt><code>EV_ERROR</code></dt>	669	<dt><code>EV_ERROR</code></dt>
587	<dd>	670	<dd>
588	<p>An unspecified error has occured, the watcher has been stopped. This might	671	<p>An unspecified error has occured, the watcher has been stopped. This might
589	happen because the watcher could not be properly started because libev	672	happen because the watcher could not be properly started because libev
…		…
597	programs, though, so beware.</p>	680	programs, though, so beware.</p>
598	</dd>	681	</dd>
599	</dl>	682	</dl>
600		683
601	</div>	684	</div>
602	<h2 id="SUMMARY_OF_GENERIC_WATCHER_FUNCTIONS">SUMMARY OF GENERIC WATCHER FUNCTIONS</h2>	685	<h2 id="GENERIC_WATCHER_FUNCTIONS">GENERIC WATCHER FUNCTIONS</h2>
603	<div id="SUMMARY_OF_GENERIC_WATCHER_FUNCTIONS-2">	686	<div id="GENERIC_WATCHER_FUNCTIONS_CONTENT">
604	<p>In the following description, <code>TYPE</code> stands for the watcher type,	687	<p>In the following description, <code>TYPE</code> stands for the watcher type,
605	e.g. <code>timer</code> for <code>ev_timer</code> watchers and <code>io</code> for <code>ev_io</code> watchers.</p>	688	e.g. <code>timer</code> for <code>ev_timer</code> watchers and <code>io</code> for <code>ev_io</code> watchers.</p>
606	<dl>	689	<dl>
607	<dt><code>ev_init</code> (ev_TYPE *watcher, callback)</dt>	690	<dt><code>ev_init</code> (ev_TYPE *watcher, callback)</dt>
608	<dd>	691	<dd>
…		…
612	the type-specific <code>ev_TYPE_set</code> macro afterwards to initialise the	695	the type-specific <code>ev_TYPE_set</code> macro afterwards to initialise the
613	type-specific parts. For each type there is also a <code>ev_TYPE_init</code> macro	696	type-specific parts. For each type there is also a <code>ev_TYPE_init</code> macro
614	which rolls both calls into one.</p>	697	which rolls both calls into one.</p>
615	<p>You can reinitialise a watcher at any time as long as it has been stopped	698	<p>You can reinitialise a watcher at any time as long as it has been stopped
616	(or never started) and there are no pending events outstanding.</p>	699	(or never started) and there are no pending events outstanding.</p>
617	<p>The callbakc is always of type <code>void ()(ev_loop loop, ev_TYPE *watcher,	700	<p>The callback is always of type <code>void ()(ev_loop loop, ev_TYPE *watcher,
618	int revents)</code>.</p>	701	int revents)</code>.</p>
619	</dd>	702	</dd>
620	<dt><code>ev_TYPE_set</code> (ev_TYPE *, [args])</dt>	703	<dt><code>ev_TYPE_set</code> (ev_TYPE *, [args])</dt>
621	<dd>	704	<dd>
622	<p>This macro initialises the type-specific parts of a watcher. You need to	705	<p>This macro initialises the type-specific parts of a watcher. You need to
…		…
659	events but its callback has not yet been invoked). As long as a watcher	742	events but its callback has not yet been invoked). As long as a watcher
660	is pending (but not active) you must not call an init function on it (but	743	is pending (but not active) you must not call an init function on it (but
661	<code>ev_TYPE_set</code> is safe) and you must make sure the watcher is available to	744	<code>ev_TYPE_set</code> is safe) and you must make sure the watcher is available to
662	libev (e.g. you cnanot <code>free ()</code> it).</p>	745	libev (e.g. you cnanot <code>free ()</code> it).</p>
663	</dd>	746	</dd>
664	<dt>callback = ev_cb (ev_TYPE *watcher)</dt>	747	<dt>callback ev_cb (ev_TYPE *watcher)</dt>
665	<dd>	748	<dd>
666	<p>Returns the callback currently set on the watcher.</p>	749	<p>Returns the callback currently set on the watcher.</p>
667	</dd>	750	</dd>
668	<dt>ev_cb_set (ev_TYPE *watcher, callback)</dt>	751	<dt>ev_cb_set (ev_TYPE *watcher, callback)</dt>
669	<dd>	752	<dd>
…		…
701	struct my_io w = (struct my_io )w_;	784	struct my_io w = (struct my_io )w_;
702	...	785	...
703	}	786	}
704		787
705	</pre>	788	</pre>
706	<p>More interesting and less C-conformant ways of catsing your callback type	789	<p>More interesting and less C-conformant ways of casting your callback type
707	have been omitted....</p>	790	instead have been omitted.</p>
		791	<p>Another common scenario is having some data structure with multiple
		792	watchers:</p>
		793	<pre> struct my_biggy
		794	{
		795	int some_data;
		796	ev_timer t1;
		797	ev_timer t2;
		798	}
708		799
		800	</pre>
		801	<p>In this case getting the pointer to <code>my_biggy</code> is a bit more complicated,
		802	you need to use <code>offsetof</code>:</p>
		803	<pre> #include <stddef.h>
709		804
		805	static void
		806	t1_cb (EV_P_ struct ev_timer *w, int revents)
		807	{
		808	struct my_biggy big = (struct my_biggy *
		809	(((char *)w) - offsetof (struct my_biggy, t1));
		810	}
710		811
		812	static void
		813	t2_cb (EV_P_ struct ev_timer *w, int revents)
		814	{
		815	struct my_biggy big = (struct my_biggy *
		816	(((char *)w) - offsetof (struct my_biggy, t2));
		817	}
711		818
712		819
		820
		821
		822	</pre>
		823
713	</div>	824	</div>
714	<h1 id="WATCHER_TYPES">WATCHER TYPES</h1><p><a href="#TOP" class="toplink">Top</a></p>	825	<h1 id="WATCHER_TYPES">WATCHER TYPES</h1>
715	<div id="WATCHER_TYPES_CONTENT">	826	<div id="WATCHER_TYPES_CONTENT">
716	<p>This section describes each watcher in detail, but will not repeat	827	<p>This section describes each watcher in detail, but will not repeat
717	information given in the last section.</p>	828	information given in the last section. Any initialisation/set macros,
		829	functions and members specific to the watcher type are explained.</p>
		830	<p>Members are additionally marked with either <i>[read-only]</i>, meaning that,
		831	while the watcher is active, you can look at the member and expect some
		832	sensible content, but you must not modify it (you can modify it while the
		833	watcher is stopped to your hearts content), or <i>[read-write]</i>, which
		834	means you can expect it to have some sensible content while the watcher
		835	is active, but you can also modify it. Modifying it may not do something
		836	sensible or take immediate effect (or do anything at all), but libev will
		837	not crash or malfunction in any way.</p>
718		838
719		839
720		840
721		841
722		842
723	</div>	843	</div>
724	<h2 id="code_ev_io_code_is_this_file_descrip"><code>ev_io</code> - is this file descriptor readable or writable</h2>	844	<h2 id="code_ev_io_code_is_this_file_descrip"><code>ev_io</code> - is this file descriptor readable or writable?</h2>
725	<div id="code_ev_io_code_is_this_file_descrip-2">	845	<div id="code_ev_io_code_is_this_file_descrip-2">
726	<p>I/O watchers check whether a file descriptor is readable or writable	846	<p>I/O watchers check whether a file descriptor is readable or writable
727	in each iteration of the event loop (This behaviour is called	847	in each iteration of the event loop, or, more precisely, when reading
728	level-triggering because you keep receiving events as long as the	848	would not block the process and writing would at least be able to write
729	condition persists. Remember you can stop the watcher if you don't want to	849	some data. This behaviour is called level-triggering because you keep
730	act on the event and neither want to receive future events).</p>	850	receiving events as long as the condition persists. Remember you can stop
		851	the watcher if you don't want to act on the event and neither want to
		852	receive future events.</p>
731	<p>In general you can register as many read and/or write event watchers per	853	<p>In general you can register as many read and/or write event watchers per
732	fd as you want (as long as you don't confuse yourself). Setting all file	854	fd as you want (as long as you don't confuse yourself). Setting all file
733	descriptors to non-blocking mode is also usually a good idea (but not	855	descriptors to non-blocking mode is also usually a good idea (but not
734	required if you know what you are doing).</p>	856	required if you know what you are doing).</p>
735	<p>You have to be careful with dup'ed file descriptors, though. Some backends	857	<p>You have to be careful with dup'ed file descriptors, though. Some backends
736	(the linux epoll backend is a notable example) cannot handle dup'ed file	858	(the linux epoll backend is a notable example) cannot handle dup'ed file
737	descriptors correctly if you register interest in two or more fds pointing	859	descriptors correctly if you register interest in two or more fds pointing
738	to the same underlying file/socket etc. description (that is, they share	860	to the same underlying file/socket/etc. description (that is, they share
739	the same underlying "file open").</p>	861	the same underlying "file open").</p>
740	<p>If you must do this, then force the use of a known-to-be-good backend	862	<p>If you must do this, then force the use of a known-to-be-good backend
741	(at the time of this writing, this includes only <code>EVBACKEND_SELECT</code> and	863	(at the time of this writing, this includes only <code>EVBACKEND_SELECT</code> and
742	<code>EVBACKEND_POLL</code>).</p>	864	<code>EVBACKEND_POLL</code>).</p>
		865	<p>Another thing you have to watch out for is that it is quite easy to
		866	receive "spurious" readyness notifications, that is your callback might
		867	be called with <code>EV_READ</code> but a subsequent <code>read</code>(2) will actually block
		868	because there is no data. Not only are some backends known to create a
		869	lot of those (for example solaris ports), it is very easy to get into
		870	this situation even with a relatively standard program structure. Thus
		871	it is best to always use non-blocking I/O: An extra <code>read</code>(2) returning
		872	<code>EAGAIN</code> is far preferable to a program hanging until some data arrives.</p>
		873	<p>If you cannot run the fd in non-blocking mode (for example you should not
		874	play around with an Xlib connection), then you have to seperately re-test
		875	wether a file descriptor is really ready with a known-to-be good interface
		876	such as poll (fortunately in our Xlib example, Xlib already does this on
		877	its own, so its quite safe to use).</p>
743	<dl>	878	<dl>
744	<dt>ev_io_init (ev_io *, callback, int fd, int events)</dt>	879	<dt>ev_io_init (ev_io *, callback, int fd, int events)</dt>
745	<dt>ev_io_set (ev_io *, int fd, int events)</dt>	880	<dt>ev_io_set (ev_io *, int fd, int events)</dt>
746	<dd>	881	<dd>
747	<p>Configures an <code>ev_io</code> watcher. The fd is the file descriptor to rceeive	882	<p>Configures an <code>ev_io</code> watcher. The <code>fd</code> is the file descriptor to
748	events for and events is either <code>EV_READ</code>, <code>EV_WRITE</code> or <code>EV_READ \|	883	rceeive events for and events is either <code>EV_READ</code>, <code>EV_WRITE</code> or
749	EV_WRITE</code> to receive the given events.</p>	884	<code>EV_READ \| EV_WRITE</code> to receive the given events.</p>
750	<p>Please note that most of the more scalable backend mechanisms (for example	885	</dd>
751	epoll and solaris ports) can result in spurious readyness notifications	886	<dt>int fd [read-only]</dt>
752	for file descriptors, so you practically need to use non-blocking I/O (and	887	<dd>
753	treat callback invocation as hint only), or retest separately with a safe	888	<p>The file descriptor being watched.</p>
754	interface before doing I/O (XLib can do this), or force the use of either	889	</dd>
755	<code>EVBACKEND_SELECT</code> or <code>EVBACKEND_POLL</code>, which don't suffer from this	890	<dt>int events [read-only]</dt>
756	problem. Also note that it is quite easy to have your callback invoked	891	<dd>
757	when the readyness condition is no longer valid even when employing	892	<p>The events being watched.</p>
758	typical ways of handling events, so its a good idea to use non-blocking
759	I/O unconditionally.</p>
760	</dd>	893	</dd>
761	</dl>	894	</dl>
762	<p>Example: call <code>stdin_readable_cb</code> when STDIN_FILENO has become, well	895	<p>Example: Call <code>stdin_readable_cb</code> when STDIN_FILENO has become, well
763	readable, but only once. Since it is likely line-buffered, you could	896	readable, but only once. Since it is likely line-buffered, you could
764	attempt to read a whole line in the callback:</p>	897	attempt to read a whole line in the callback.</p>
765	<pre> static void	898	<pre> static void
766	stdin_readable_cb (struct ev_loop loop, struct ev_io w, int revents)	899	stdin_readable_cb (struct ev_loop loop, struct ev_io w, int revents)
767	{	900	{
768	ev_io_stop (loop, w);	901	ev_io_stop (loop, w);
769	.. read from stdin here (or from w->fd) and haqndle any I/O errors	902	.. read from stdin here (or from w->fd) and haqndle any I/O errors
…		…
780		913
781		914
782	</pre>	915	</pre>
783		916
784	</div>	917	</div>
785	<h2 id="code_ev_timer_code_relative_and_opti"><code>ev_timer</code> - relative and optionally recurring timeouts</h2>	918	<h2 id="code_ev_timer_code_relative_and_opti"><code>ev_timer</code> - relative and optionally repeating timeouts</h2>
786	<div id="code_ev_timer_code_relative_and_opti-2">	919	<div id="code_ev_timer_code_relative_and_opti-2">
787	<p>Timer watchers are simple relative timers that generate an event after a	920	<p>Timer watchers are simple relative timers that generate an event after a
788	given time, and optionally repeating in regular intervals after that.</p>	921	given time, and optionally repeating in regular intervals after that.</p>
789	<p>The timers are based on real time, that is, if you register an event that	922	<p>The timers are based on real time, that is, if you register an event that
790	times out after an hour and you reset your system clock to last years	923	times out after an hour and you reset your system clock to last years
…		…
822	repeating. The exact semantics are:</p>	955	repeating. The exact semantics are:</p>
823	<p>If the timer is started but nonrepeating, stop it.</p>	956	<p>If the timer is started but nonrepeating, stop it.</p>
824	<p>If the timer is repeating, either start it if necessary (with the repeat	957	<p>If the timer is repeating, either start it if necessary (with the repeat
825	value), or reset the running timer to the repeat value.</p>	958	value), or reset the running timer to the repeat value.</p>
826	<p>This sounds a bit complicated, but here is a useful and typical	959	<p>This sounds a bit complicated, but here is a useful and typical
827	example: Imagine you have a tcp connection and you want a so-called idle	960	example: Imagine you have a tcp connection and you want a so-called
828	timeout, that is, you want to be called when there have been, say, 60	961	idle timeout, that is, you want to be called when there have been,
829	seconds of inactivity on the socket. The easiest way to do this is to	962	say, 60 seconds of inactivity on the socket. The easiest way to do
830	configure an <code>ev_timer</code> with after=repeat=60 and calling ev_timer_again each	963	this is to configure an <code>ev_timer</code> with <code>after</code>=<code>repeat</code>=<code>60</code> and calling
831	time you successfully read or write some data. If you go into an idle	964	<code>ev_timer_again</code> each time you successfully read or write some data. If
832	state where you do not expect data to travel on the socket, you can stop	965	you go into an idle state where you do not expect data to travel on the
833	the timer, and again will automatically restart it if need be.</p>	966	socket, you can stop the timer, and again will automatically restart it if
		967	need be.</p>
		968	<p>You can also ignore the <code>after</code> value and <code>ev_timer_start</code> altogether
		969	and only ever use the <code>repeat</code> value:</p>
		970	<pre> ev_timer_init (timer, callback, 0., 5.);
		971	ev_timer_again (loop, timer);
		972	...
		973	timer->again = 17.;
		974	ev_timer_again (loop, timer);
		975	...
		976	timer->again = 10.;
		977	ev_timer_again (loop, timer);
		978
		979	</pre>
		980	<p>This is more efficient then stopping/starting the timer eahc time you want
		981	to modify its timeout value.</p>
		982	</dd>
		983	<dt>ev_tstamp repeat [read-write]</dt>
		984	<dd>
		985	<p>The current <code>repeat</code> value. Will be used each time the watcher times out
		986	or <code>ev_timer_again</code> is called and determines the next timeout (if any),
		987	which is also when any modifications are taken into account.</p>
834	</dd>	988	</dd>
835	</dl>	989	</dl>
836	<p>Example: create a timer that fires after 60 seconds.</p>	990	<p>Example: Create a timer that fires after 60 seconds.</p>
837	<pre> static void	991	<pre> static void
838	one_minute_cb (struct ev_loop loop, struct ev_timer w, int revents)	992	one_minute_cb (struct ev_loop loop, struct ev_timer w, int revents)
839	{	993	{
840	.. one minute over, w is actually stopped right here	994	.. one minute over, w is actually stopped right here
841	}	995	}
…		…
843	struct ev_timer mytimer;	997	struct ev_timer mytimer;
844	ev_timer_init (&mytimer, one_minute_cb, 60., 0.);	998	ev_timer_init (&mytimer, one_minute_cb, 60., 0.);
845	ev_timer_start (loop, &mytimer);	999	ev_timer_start (loop, &mytimer);
846		1000
847	</pre>	1001	</pre>
848	<p>Example: create a timeout timer that times out after 10 seconds of	1002	<p>Example: Create a timeout timer that times out after 10 seconds of
849	inactivity.</p>	1003	inactivity.</p>
850	<pre> static void	1004	<pre> static void
851	timeout_cb (struct ev_loop loop, struct ev_timer w, int revents)	1005	timeout_cb (struct ev_loop loop, struct ev_timer w, int revents)
852	{	1006	{
853	.. ten seconds without any activity	1007	.. ten seconds without any activity
…		…
866		1020
867		1021
868	</pre>	1022	</pre>
869		1023
870	</div>	1024	</div>
871	<h2 id="code_ev_periodic_code_to_cron_or_not"><code>ev_periodic</code> - to cron or not to cron</h2>	1025	<h2 id="code_ev_periodic_code_to_cron_or_not"><code>ev_periodic</code> - to cron or not to cron?</h2>
872	<div id="code_ev_periodic_code_to_cron_or_not-2">	1026	<div id="code_ev_periodic_code_to_cron_or_not-2">
873	<p>Periodic watchers are also timers of a kind, but they are very versatile	1027	<p>Periodic watchers are also timers of a kind, but they are very versatile
874	(and unfortunately a bit complex).</p>	1028	(and unfortunately a bit complex).</p>
875	<p>Unlike <code>ev_timer</code>'s, they are not based on real time (or relative time)	1029	<p>Unlike <code>ev_timer</code>'s, they are not based on real time (or relative time)
876	but on wallclock time (absolute time). You can tell a periodic watcher	1030	but on wallclock time (absolute time). You can tell a periodic watcher
877	to trigger "at" some specific point in time. For example, if you tell a	1031	to trigger "at" some specific point in time. For example, if you tell a
878	periodic watcher to trigger in 10 seconds (by specifiying e.g. c<ev_now ()	1032	periodic watcher to trigger in 10 seconds (by specifiying e.g. <code>ev_now ()
879	+ 10.>) and then reset your system clock to the last year, then it will	1033	+ 10.</code>) and then reset your system clock to the last year, then it will
880	take a year to trigger the event (unlike an <code>ev_timer</code>, which would trigger	1034	take a year to trigger the event (unlike an <code>ev_timer</code>, which would trigger
881	roughly 10 seconds later and of course not if you reset your system time	1035	roughly 10 seconds later and of course not if you reset your system time
882	again).</p>	1036	again).</p>
883	<p>They can also be used to implement vastly more complex timers, such as	1037	<p>They can also be used to implement vastly more complex timers, such as
884	triggering an event on eahc midnight, local time.</p>	1038	triggering an event on eahc midnight, local time.</p>
…		…
956	<p>Simply stops and restarts the periodic watcher again. This is only useful	1110	<p>Simply stops and restarts the periodic watcher again. This is only useful
957	when you changed some parameters or the reschedule callback would return	1111	when you changed some parameters or the reschedule callback would return
958	a different time than the last time it was called (e.g. in a crond like	1112	a different time than the last time it was called (e.g. in a crond like
959	program when the crontabs have changed).</p>	1113	program when the crontabs have changed).</p>
960	</dd>	1114	</dd>
		1115	<dt>ev_tstamp interval [read-write]</dt>
		1116	<dd>
		1117	<p>The current interval value. Can be modified any time, but changes only
		1118	take effect when the periodic timer fires or <code>ev_periodic_again</code> is being
		1119	called.</p>
		1120	</dd>
		1121	<dt>ev_tstamp (reschedule_cb)(struct ev_periodic w, ev_tstamp now) [read-write]</dt>
		1122	<dd>
		1123	<p>The current reschedule callback, or <code>0</code>, if this functionality is
		1124	switched off. Can be changed any time, but changes only take effect when
		1125	the periodic timer fires or <code>ev_periodic_again</code> is being called.</p>
		1126	</dd>
961	</dl>	1127	</dl>
962	<p>Example: call a callback every hour, or, more precisely, whenever the	1128	<p>Example: Call a callback every hour, or, more precisely, whenever the
963	system clock is divisible by 3600. The callback invocation times have	1129	system clock is divisible by 3600. The callback invocation times have
964	potentially a lot of jittering, but good long-term stability.</p>	1130	potentially a lot of jittering, but good long-term stability.</p>
965	<pre> static void	1131	<pre> static void
966	clock_cb (struct ev_loop loop, struct ev_io w, int revents)	1132	clock_cb (struct ev_loop loop, struct ev_io w, int revents)
967	{	1133	{
…		…
971	struct ev_periodic hourly_tick;	1137	struct ev_periodic hourly_tick;
972	ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0);	1138	ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0);
973	ev_periodic_start (loop, &hourly_tick);	1139	ev_periodic_start (loop, &hourly_tick);
974		1140
975	</pre>	1141	</pre>
976	<p>Example: the same as above, but use a reschedule callback to do it:</p>	1142	<p>Example: The same as above, but use a reschedule callback to do it:</p>
977	<pre> #include <math.h>	1143	<pre> #include <math.h>
978		1144
979	static ev_tstamp	1145	static ev_tstamp
980	my_scheduler_cb (struct ev_periodic *w, ev_tstamp now)	1146	my_scheduler_cb (struct ev_periodic *w, ev_tstamp now)
981	{	1147	{
…		…
983	}	1149	}
984		1150
985	ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb);	1151	ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb);
986		1152
987	</pre>	1153	</pre>
988	<p>Example: call a callback every hour, starting now:</p>	1154	<p>Example: Call a callback every hour, starting now:</p>
989	<pre> struct ev_periodic hourly_tick;	1155	<pre> struct ev_periodic hourly_tick;
990	ev_periodic_init (&hourly_tick, clock_cb,	1156	ev_periodic_init (&hourly_tick, clock_cb,
991	fmod (ev_now (loop), 3600.), 3600., 0);	1157	fmod (ev_now (loop), 3600.), 3600., 0);
992	ev_periodic_start (loop, &hourly_tick);	1158	ev_periodic_start (loop, &hourly_tick);
993		1159
…		…
995		1161
996		1162
997	</pre>	1163	</pre>
998		1164
999	</div>	1165	</div>
1000	<h2 id="code_ev_signal_code_signal_me_when_a"><code>ev_signal</code> - signal me when a signal gets signalled</h2>	1166	<h2 id="code_ev_signal_code_signal_me_when_a"><code>ev_signal</code> - signal me when a signal gets signalled!</h2>
1001	<div id="code_ev_signal_code_signal_me_when_a-2">	1167	<div id="code_ev_signal_code_signal_me_when_a-2">
1002	<p>Signal watchers will trigger an event when the process receives a specific	1168	<p>Signal watchers will trigger an event when the process receives a specific
1003	signal one or more times. Even though signals are very asynchronous, libev	1169	signal one or more times. Even though signals are very asynchronous, libev
1004	will try it's best to deliver signals synchronously, i.e. as part of the	1170	will try it's best to deliver signals synchronously, i.e. as part of the
1005	normal event processing, like any other event.</p>	1171	normal event processing, like any other event.</p>
…		…
1014	<dt>ev_signal_set (ev_signal *, int signum)</dt>	1180	<dt>ev_signal_set (ev_signal *, int signum)</dt>
1015	<dd>	1181	<dd>
1016	<p>Configures the watcher to trigger on the given signal number (usually one	1182	<p>Configures the watcher to trigger on the given signal number (usually one
1017	of the <code>SIGxxx</code> constants).</p>	1183	of the <code>SIGxxx</code> constants).</p>
1018	</dd>	1184	</dd>
		1185	<dt>int signum [read-only]</dt>
		1186	<dd>
		1187	<p>The signal the watcher watches out for.</p>
		1188	</dd>
1019	</dl>	1189	</dl>
1020		1190
1021		1191
1022		1192
1023		1193
1024		1194
1025	</div>	1195	</div>
1026	<h2 id="code_ev_child_code_wait_for_pid_stat"><code>ev_child</code> - wait for pid status changes</h2>	1196	<h2 id="code_ev_child_code_watch_out_for_pro"><code>ev_child</code> - watch out for process status changes</h2>
1027	<div id="code_ev_child_code_wait_for_pid_stat-2">	1197	<div id="code_ev_child_code_watch_out_for_pro-2">
1028	<p>Child watchers trigger when your process receives a SIGCHLD in response to	1198	<p>Child watchers trigger when your process receives a SIGCHLD in response to
1029	some child status changes (most typically when a child of yours dies).</p>	1199	some child status changes (most typically when a child of yours dies).</p>
1030	<dl>	1200	<dl>
1031	<dt>ev_child_init (ev_child *, callback, int pid)</dt>	1201	<dt>ev_child_init (ev_child *, callback, int pid)</dt>
1032	<dt>ev_child_set (ev_child *, int pid)</dt>	1202	<dt>ev_child_set (ev_child *, int pid)</dt>
…		…
1036	at the <code>rstatus</code> member of the <code>ev_child</code> watcher structure to see	1206	at the <code>rstatus</code> member of the <code>ev_child</code> watcher structure to see
1037	the status word (use the macros from <code>sys/wait.h</code> and see your systems	1207	the status word (use the macros from <code>sys/wait.h</code> and see your systems
1038	<code>waitpid</code> documentation). The <code>rpid</code> member contains the pid of the	1208	<code>waitpid</code> documentation). The <code>rpid</code> member contains the pid of the
1039	process causing the status change.</p>	1209	process causing the status change.</p>
1040	</dd>	1210	</dd>
		1211	<dt>int pid [read-only]</dt>
		1212	<dd>
		1213	<p>The process id this watcher watches out for, or <code>0</code>, meaning any process id.</p>
		1214	</dd>
		1215	<dt>int rpid [read-write]</dt>
		1216	<dd>
		1217	<p>The process id that detected a status change.</p>
		1218	</dd>
		1219	<dt>int rstatus [read-write]</dt>
		1220	<dd>
		1221	<p>The process exit/trace status caused by <code>rpid</code> (see your systems
		1222	<code>waitpid</code> and <code>sys/wait.h</code> documentation for details).</p>
		1223	</dd>
1041	</dl>	1224	</dl>
1042	<p>Example: try to exit cleanly on SIGINT and SIGTERM.</p>	1225	<p>Example: Try to exit cleanly on SIGINT and SIGTERM.</p>
1043	<pre> static void	1226	<pre> static void
1044	sigint_cb (struct ev_loop loop, struct ev_signal w, int revents)	1227	sigint_cb (struct ev_loop loop, struct ev_signal w, int revents)
1045	{	1228	{
1046	ev_unloop (loop, EVUNLOOP_ALL);	1229	ev_unloop (loop, EVUNLOOP_ALL);
1047	}	1230	}
…		…
1054		1237
1055		1238
1056	</pre>	1239	</pre>
1057		1240
1058	</div>	1241	</div>
		1242	<h2 id="code_ev_stat_code_did_the_file_attri"><code>ev_stat</code> - did the file attributes just change?</h2>
		1243	<div id="code_ev_stat_code_did_the_file_attri-2">
		1244	<p>This watches a filesystem path for attribute changes. That is, it calls
		1245	<code>stat</code> regularly (or when the OS says it changed) and sees if it changed
		1246	compared to the last time, invoking the callback if it did.</p>
		1247	<p>The path does not need to exist: changing from "path exists" to "path does
		1248	not exist" is a status change like any other. The condition "path does
		1249	not exist" is signified by the <code>st_nlink</code> field being zero (which is
		1250	otherwise always forced to be at least one) and all the other fields of
		1251	the stat buffer having unspecified contents.</p>
		1252	<p>Since there is no standard to do this, the portable implementation simply
		1253	calls <code>stat (2)</code> regularly on the path to see if it changed somehow. You
		1254	can specify a recommended polling interval for this case. If you specify
		1255	a polling interval of <code>0</code> (highly recommended!) then a <i>suitable,
		1256	unspecified default</i> value will be used (which you can expect to be around
		1257	five seconds, although this might change dynamically). Libev will also
		1258	impose a minimum interval which is currently around <code>0.1</code>, but thats
		1259	usually overkill.</p>
		1260	<p>This watcher type is not meant for massive numbers of stat watchers,
		1261	as even with OS-supported change notifications, this can be
		1262	resource-intensive.</p>
		1263	<p>At the time of this writing, only the Linux inotify interface is
		1264	implemented (implementing kqueue support is left as an exercise for the
		1265	reader). Inotify will be used to give hints only and should not change the
		1266	semantics of <code>ev_stat</code> watchers, which means that libev sometimes needs
		1267	to fall back to regular polling again even with inotify, but changes are
		1268	usually detected immediately, and if the file exists there will be no
		1269	polling.</p>
		1270	<dl>
		1271	<dt>ev_stat_init (ev_stat , callback, const char path, ev_tstamp interval)</dt>
		1272	<dt>ev_stat_set (ev_stat , const char path, ev_tstamp interval)</dt>
		1273	<dd>
		1274	<p>Configures the watcher to wait for status changes of the given
		1275	<code>path</code>. The <code>interval</code> is a hint on how quickly a change is expected to
		1276	be detected and should normally be specified as <code>0</code> to let libev choose
		1277	a suitable value. The memory pointed to by <code>path</code> must point to the same
		1278	path for as long as the watcher is active.</p>
		1279	<p>The callback will be receive <code>EV_STAT</code> when a change was detected,
		1280	relative to the attributes at the time the watcher was started (or the
		1281	last change was detected).</p>
		1282	</dd>
		1283	<dt>ev_stat_stat (ev_stat *)</dt>
		1284	<dd>
		1285	<p>Updates the stat buffer immediately with new values. If you change the
		1286	watched path in your callback, you could call this fucntion to avoid
		1287	detecting this change (while introducing a race condition). Can also be
		1288	useful simply to find out the new values.</p>
		1289	</dd>
		1290	<dt>ev_statdata attr [read-only]</dt>
		1291	<dd>
		1292	<p>The most-recently detected attributes of the file. Although the type is of
		1293	<code>ev_statdata</code>, this is usually the (or one of the) <code>struct stat</code> types
		1294	suitable for your system. If the <code>st_nlink</code> member is <code>0</code>, then there
		1295	was some error while <code>stat</code>ing the file.</p>
		1296	</dd>
		1297	<dt>ev_statdata prev [read-only]</dt>
		1298	<dd>
		1299	<p>The previous attributes of the file. The callback gets invoked whenever
		1300	<code>prev</code> != <code>attr</code>.</p>
		1301	</dd>
		1302	<dt>ev_tstamp interval [read-only]</dt>
		1303	<dd>
		1304	<p>The specified interval.</p>
		1305	</dd>
		1306	<dt>const char *path [read-only]</dt>
		1307	<dd>
		1308	<p>The filesystem path that is being watched.</p>
		1309	</dd>
		1310	</dl>
		1311	<p>Example: Watch <code>/etc/passwd</code> for attribute changes.</p>
		1312	<pre> static void
		1313	passwd_cb (struct ev_loop loop, ev_stat w, int revents)
		1314	{
		1315	/* /etc/passwd changed in some way */
		1316	if (w->attr.st_nlink)
		1317	{
		1318	printf ("passwd current size %ld\n", (long)w->attr.st_size);
		1319	printf ("passwd current atime %ld\n", (long)w->attr.st_mtime);
		1320	printf ("passwd current mtime %ld\n", (long)w->attr.st_mtime);
		1321	}
		1322	else
		1323	/* you shalt not abuse printf for puts */
		1324	puts ("wow, /etc/passwd is not there, expect problems. "
		1325	"if this is windows, they already arrived\n");
		1326	}
		1327
		1328	...
		1329	ev_stat passwd;
		1330
		1331	ev_stat_init (&passwd, passwd_cb, "/etc/passwd");
		1332	ev_stat_start (loop, &passwd);
		1333
		1334
		1335
		1336
		1337	</pre>
		1338
		1339	</div>
1059	<h2 id="code_ev_idle_code_when_you_ve_got_no"><code>ev_idle</code> - when you've got nothing better to do</h2>	1340	<h2 id="code_ev_idle_code_when_you_ve_got_no"><code>ev_idle</code> - when you've got nothing better to do...</h2>
1060	<div id="code_ev_idle_code_when_you_ve_got_no-2">	1341	<div id="code_ev_idle_code_when_you_ve_got_no-2">
1061	<p>Idle watchers trigger events when there are no other events are pending	1342	<p>Idle watchers trigger events when there are no other events are pending
1062	(prepare, check and other idle watchers do not count). That is, as long	1343	(prepare, check and other idle watchers do not count). That is, as long
1063	as your process is busy handling sockets or timeouts (or even signals,	1344	as your process is busy handling sockets or timeouts (or even signals,
1064	imagine) it will not be triggered. But when your process is idle all idle	1345	imagine) it will not be triggered. But when your process is idle all idle
…		…
1077	<p>Initialises and configures the idle watcher - it has no parameters of any	1358	<p>Initialises and configures the idle watcher - it has no parameters of any
1078	kind. There is a <code>ev_idle_set</code> macro, but using it is utterly pointless,	1359	kind. There is a <code>ev_idle_set</code> macro, but using it is utterly pointless,
1079	believe me.</p>	1360	believe me.</p>
1080	</dd>	1361	</dd>
1081	</dl>	1362	</dl>
1082	<p>Example: dynamically allocate an <code>ev_idle</code>, start it, and in the	1363	<p>Example: Dynamically allocate an <code>ev_idle</code> watcher, start it, and in the
1083	callback, free it. Alos, use no error checking, as usual.</p>	1364	callback, free it. Also, use no error checking, as usual.</p>
1084	<pre> static void	1365	<pre> static void
1085	idle_cb (struct ev_loop loop, struct ev_idle w, int revents)	1366	idle_cb (struct ev_loop loop, struct ev_idle w, int revents)
1086	{	1367	{
1087	free (w);	1368	free (w);
1088	// now do something you wanted to do when the program has	1369	// now do something you wanted to do when the program has
…		…
1097		1378
1098		1379
1099	</pre>	1380	</pre>
1100		1381
1101	</div>	1382	</div>
1102	<h2 id="code_ev_prepare_code_and_code_ev_che"><code>ev_prepare</code> and <code>ev_check</code> - customise your event loop</h2>	1383	<h2 id="code_ev_prepare_code_and_code_ev_che"><code>ev_prepare</code> and <code>ev_check</code> - customise your event loop!</h2>
1103	<div id="code_ev_prepare_code_and_code_ev_che-2">	1384	<div id="code_ev_prepare_code_and_code_ev_che-2">
1104	<p>Prepare and check watchers are usually (but not always) used in tandem:	1385	<p>Prepare and check watchers are usually (but not always) used in tandem:
1105	prepare watchers get invoked before the process blocks and check watchers	1386	prepare watchers get invoked before the process blocks and check watchers
1106	afterwards.</p>	1387	afterwards.</p>
		1388	<p>You <i>must not</i> call <code>ev_loop</code> or similar functions that enter
		1389	the current event loop from either <code>ev_prepare</code> or <code>ev_check</code>
		1390	watchers. Other loops than the current one are fine, however. The
		1391	rationale behind this is that you do not need to check for recursion in
		1392	those watchers, i.e. the sequence will always be <code>ev_prepare</code>, blocking,
		1393	<code>ev_check</code> so if you have one watcher of each kind they will always be
		1394	called in pairs bracketing the blocking call.</p>
1107	<p>Their main purpose is to integrate other event mechanisms into libev and	1395	<p>Their main purpose is to integrate other event mechanisms into libev and
1108	their use is somewhat advanced. This could be used, for example, to track	1396	their use is somewhat advanced. This could be used, for example, to track
1109	variable changes, implement your own watchers, integrate net-snmp or a	1397	variable changes, implement your own watchers, integrate net-snmp or a
1110	coroutine library and lots more.</p>	1398	coroutine library and lots more. They are also occasionally useful if
		1399	you cache some data and want to flush it before blocking (for example,
		1400	in X programs you might want to do an <code>XFlush ()</code> in an <code>ev_prepare</code>
		1401	watcher).</p>
1111	<p>This is done by examining in each prepare call which file descriptors need	1402	<p>This is done by examining in each prepare call which file descriptors need
1112	to be watched by the other library, registering <code>ev_io</code> watchers for	1403	to be watched by the other library, registering <code>ev_io</code> watchers for
1113	them and starting an <code>ev_timer</code> watcher for any timeouts (many libraries	1404	them and starting an <code>ev_timer</code> watcher for any timeouts (many libraries
1114	provide just this functionality). Then, in the check watcher you check for	1405	provide just this functionality). Then, in the check watcher you check for
1115	any events that occured (by checking the pending status of all watchers	1406	any events that occured (by checking the pending status of all watchers
…		…
1131	<p>Initialises and configures the prepare or check watcher - they have no	1422	<p>Initialises and configures the prepare or check watcher - they have no
1132	parameters of any kind. There are <code>ev_prepare_set</code> and <code>ev_check_set</code>	1423	parameters of any kind. There are <code>ev_prepare_set</code> and <code>ev_check_set</code>
1133	macros, but using them is utterly, utterly and completely pointless.</p>	1424	macros, but using them is utterly, utterly and completely pointless.</p>
1134	</dd>	1425	</dd>
1135	</dl>	1426	</dl>
1136	<p>Example: TODO.</p>	1427	<p>Example: To include a library such as adns, you would add IO watchers
		1428	and a timeout watcher in a prepare handler, as required by libadns, and
		1429	in a check watcher, destroy them and call into libadns. What follows is
		1430	pseudo-code only of course:</p>
		1431	<pre> static ev_io iow [nfd];
		1432	static ev_timer tw;
1137		1433
		1434	static void
		1435	io_cb (ev_loop loop, ev_io w, int revents)
		1436	{
		1437	// set the relevant poll flags
		1438	// could also call adns_processreadable etc. here
		1439	struct pollfd fd = (struct pollfd )w->data;
		1440	if (revents & EV_READ ) fd->revents \|= fd->events & POLLIN;
		1441	if (revents & EV_WRITE) fd->revents \|= fd->events & POLLOUT;
		1442	}
1138		1443
		1444	// create io watchers for each fd and a timer before blocking
		1445	static void
		1446	adns_prepare_cb (ev_loop loop, ev_prepare w, int revents)
		1447	{
		1448	int timeout = 3600000;truct pollfd fds [nfd];
		1449	// actual code will need to loop here and realloc etc.
		1450	adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ()));
1139		1451
		1452	/* the callback is illegal, but won't be called as we stop during check */
		1453	ev_timer_init (&tw, 0, timeout * 1e-3);
		1454	ev_timer_start (loop, &tw);
1140		1455
		1456	// create on ev_io per pollfd
		1457	for (int i = 0; i < nfd; ++i)
		1458	{
		1459	ev_io_init (iow + i, io_cb, fds [i].fd,
		1460	((fds [i].events & POLLIN ? EV_READ : 0)
		1461	\| (fds [i].events & POLLOUT ? EV_WRITE : 0)));
1141		1462
		1463	fds [i].revents = 0;
		1464	iow [i].data = fds + i;
		1465	ev_io_start (loop, iow + i);
		1466	}
		1467	}
		1468
		1469	// stop all watchers after blocking
		1470	static void
		1471	adns_check_cb (ev_loop loop, ev_check w, int revents)
		1472	{
		1473	ev_timer_stop (loop, &tw);
		1474
		1475	for (int i = 0; i < nfd; ++i)
		1476	ev_io_stop (loop, iow + i);
		1477
		1478	adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop));
		1479	}
		1480
		1481
		1482
		1483
		1484	</pre>
		1485
1142	</div>	1486	</div>
1143	<h2 id="code_ev_embed_code_when_one_backend_"><code>ev_embed</code> - when one backend isn't enough</h2>	1487	<h2 id="code_ev_embed_code_when_one_backend_"><code>ev_embed</code> - when one backend isn't enough...</h2>
1144	<div id="code_ev_embed_code_when_one_backend_-2">	1488	<div id="code_ev_embed_code_when_one_backend_-2">
1145	<p>This is a rather advanced watcher type that lets you embed one event loop	1489	<p>This is a rather advanced watcher type that lets you embed one event loop
1146	into another (currently only <code>ev_io</code> events are supported in the embedded	1490	into another (currently only <code>ev_io</code> events are supported in the embedded
1147	loop, other types of watchers might be handled in a delayed or incorrect	1491	loop, other types of watchers might be handled in a delayed or incorrect
1148	fashion and must not be used).</p>	1492	fashion and must not be used).</p>
…		…
1216	<dd>	1560	<dd>
1217	<p>Make a single, non-blocking sweep over the embedded loop. This works	1561	<p>Make a single, non-blocking sweep over the embedded loop. This works
1218	similarly to <code>ev_loop (embedded_loop, EVLOOP_NONBLOCK)</code>, but in the most	1562	similarly to <code>ev_loop (embedded_loop, EVLOOP_NONBLOCK)</code>, but in the most
1219	apropriate way for embedded loops.</p>	1563	apropriate way for embedded loops.</p>
1220	</dd>	1564	</dd>
		1565	<dt>struct ev_loop *loop [read-only]</dt>
		1566	<dd>
		1567	<p>The embedded event loop.</p>
		1568	</dd>
1221	</dl>	1569	</dl>
1222		1570
1223		1571
1224		1572
1225		1573
1226		1574
1227	</div>	1575	</div>
1228	<h1 id="OTHER_FUNCTIONS">OTHER FUNCTIONS</h1><p><a href="#TOP" class="toplink">Top</a></p>	1576	<h2 id="code_ev_fork_code_the_audacity_to_re"><code>ev_fork</code> - the audacity to resume the event loop after a fork</h2>
		1577	<div id="code_ev_fork_code_the_audacity_to_re-2">
		1578	<p>Fork watchers are called when a <code>fork ()</code> was detected (usually because
		1579	whoever is a good citizen cared to tell libev about it by calling
		1580	<code>ev_default_fork</code> or <code>ev_loop_fork</code>). The invocation is done before the
		1581	event loop blocks next and before <code>ev_check</code> watchers are being called,
		1582	and only in the child after the fork. If whoever good citizen calling
		1583	<code>ev_default_fork</code> cheats and calls it in the wrong process, the fork
		1584	handlers will be invoked, too, of course.</p>
		1585	<dl>
		1586	<dt>ev_fork_init (ev_signal *, callback)</dt>
		1587	<dd>
		1588	<p>Initialises and configures the fork watcher - it has no parameters of any
		1589	kind. There is a <code>ev_fork_set</code> macro, but using it is utterly pointless,
		1590	believe me.</p>
		1591	</dd>
		1592	</dl>
		1593
		1594
		1595
		1596
		1597
		1598	</div>
		1599	<h1 id="OTHER_FUNCTIONS">OTHER FUNCTIONS</h1>
1229	<div id="OTHER_FUNCTIONS_CONTENT">	1600	<div id="OTHER_FUNCTIONS_CONTENT">
1230	<p>There are some other functions of possible interest. Described. Here. Now.</p>	1601	<p>There are some other functions of possible interest. Described. Here. Now.</p>
1231	<dl>	1602	<dl>
1232	<dt>ev_once (loop, int fd, int events, ev_tstamp timeout, callback)</dt>	1603	<dt>ev_once (loop, int fd, int events, ev_tstamp timeout, callback)</dt>
1233	<dd>	1604	<dd>
…		…
1280		1651
1281		1652
1282		1653
1283		1654
1284	</div>	1655	</div>
1285	<h1 id="LIBEVENT_EMULATION">LIBEVENT EMULATION</h1><p><a href="#TOP" class="toplink">Top</a></p>	1656	<h1 id="LIBEVENT_EMULATION">LIBEVENT EMULATION</h1>
1286	<div id="LIBEVENT_EMULATION_CONTENT">	1657	<div id="LIBEVENT_EMULATION_CONTENT">
1287	<p>Libev offers a compatibility emulation layer for libevent. It cannot	1658	<p>Libev offers a compatibility emulation layer for libevent. It cannot
1288	emulate the internals of libevent, so here are some usage hints:</p>	1659	emulate the internals of libevent, so here are some usage hints:</p>
1289	<dl>	1660	<dl>
1290	<dt>* Use it by including <event.h>, as usual.</dt>	1661	<dt>* Use it by including <event.h>, as usual.</dt>
…		…
1300	<dt>* The libev emulation is <i>not</i> ABI compatible to libevent, you need	1671	<dt>* The libev emulation is <i>not</i> ABI compatible to libevent, you need
1301	to use the libev header file and library.</dt>	1672	to use the libev header file and library.</dt>
1302	</dl>	1673	</dl>
1303		1674
1304	</div>	1675	</div>
1305	<h1 id="C_SUPPORT">C++ SUPPORT</h1><p><a href="#TOP" class="toplink">Top</a></p>	1676	<h1 id="C_SUPPORT">C++ SUPPORT</h1>
1306	<div id="C_SUPPORT_CONTENT">	1677	<div id="C_SUPPORT_CONTENT">
1307	<p>TBD.</p>	1678	<p>Libev comes with some simplistic wrapper classes for C++ that mainly allow
		1679	you to use some convinience methods to start/stop watchers and also change
		1680	the callback model to a model using method callbacks on objects.</p>
		1681	<p>To use it,</p>
		1682	<pre> #include <ev++.h>
1308		1683
		1684	</pre>
		1685	<p>(it is not installed by default). This automatically includes <cite>ev.h</cite>
		1686	and puts all of its definitions (many of them macros) into the global
		1687	namespace. All C++ specific things are put into the <code>ev</code> namespace.</p>
		1688	<p>It should support all the same embedding options as <cite>ev.h</cite>, most notably
		1689	<code>EV_MULTIPLICITY</code>.</p>
		1690	<p>Here is a list of things available in the <code>ev</code> namespace:</p>
		1691	<dl>
		1692	<dt><code>ev::READ</code>, <code>ev::WRITE</code> etc.</dt>
		1693	<dd>
		1694	<p>These are just enum values with the same values as the <code>EV_READ</code> etc.
		1695	macros from <cite>ev.h</cite>.</p>
		1696	</dd>
		1697	<dt><code>ev::tstamp</code>, <code>ev::now</code></dt>
		1698	<dd>
		1699	<p>Aliases to the same types/functions as with the <code>ev_</code> prefix.</p>
		1700	</dd>
		1701	<dt><code>ev::io</code>, <code>ev::timer</code>, <code>ev::periodic</code>, <code>ev::idle</code>, <code>ev::sig</code> etc.</dt>
		1702	<dd>
		1703	<p>For each <code>ev_TYPE</code> watcher in <cite>ev.h</cite> there is a corresponding class of
		1704	the same name in the <code>ev</code> namespace, with the exception of <code>ev_signal</code>
		1705	which is called <code>ev::sig</code> to avoid clashes with the <code>signal</code> macro
		1706	defines by many implementations.</p>
		1707	<p>All of those classes have these methods:</p>
		1708	<p>
		1709	<dl>
		1710	<dt>ev::TYPE::TYPE (object , object::method )</dt>
		1711	<dt>ev::TYPE::TYPE (object , object::method , struct ev_loop *)</dt>
		1712	<dt>ev::TYPE::~TYPE</dt>
		1713	<dd>
		1714	<p>The constructor takes a pointer to an object and a method pointer to
		1715	the event handler callback to call in this class. The constructor calls
		1716	<code>ev_init</code> for you, which means you have to call the <code>set</code> method
		1717	before starting it. If you do not specify a loop then the constructor
		1718	automatically associates the default loop with this watcher.</p>
		1719	<p>The destructor automatically stops the watcher if it is active.</p>
		1720	</dd>
		1721	<dt>w->set (struct ev_loop *)</dt>
		1722	<dd>
		1723	<p>Associates a different <code>struct ev_loop</code> with this watcher. You can only
		1724	do this when the watcher is inactive (and not pending either).</p>
		1725	</dd>
		1726	<dt>w->set ([args])</dt>
		1727	<dd>
		1728	<p>Basically the same as <code>ev_TYPE_set</code>, with the same args. Must be
		1729	called at least once. Unlike the C counterpart, an active watcher gets
		1730	automatically stopped and restarted.</p>
		1731	</dd>
		1732	<dt>w->start ()</dt>
		1733	<dd>
		1734	<p>Starts the watcher. Note that there is no <code>loop</code> argument as the
		1735	constructor already takes the loop.</p>
		1736	</dd>
		1737	<dt>w->stop ()</dt>
		1738	<dd>
		1739	<p>Stops the watcher if it is active. Again, no <code>loop</code> argument.</p>
		1740	</dd>
		1741	<dt>w->again () <code>ev::timer</code>, <code>ev::periodic</code> only</dt>
		1742	<dd>
		1743	<p>For <code>ev::timer</code> and <code>ev::periodic</code>, this invokes the corresponding
		1744	<code>ev_TYPE_again</code> function.</p>
		1745	</dd>
		1746	<dt>w->sweep () <code>ev::embed</code> only</dt>
		1747	<dd>
		1748	<p>Invokes <code>ev_embed_sweep</code>.</p>
		1749	</dd>
		1750	<dt>w->update () <code>ev::stat</code> only</dt>
		1751	<dd>
		1752	<p>Invokes <code>ev_stat_stat</code>.</p>
		1753	</dd>
		1754	</dl>
		1755	</p>
		1756	</dd>
		1757	</dl>
		1758	<p>Example: Define a class with an IO and idle watcher, start one of them in
		1759	the constructor.</p>
		1760	<pre> class myclass
		1761	{
		1762	ev_io io; void io_cb (ev::io &w, int revents);
		1763	ev_idle idle void idle_cb (ev::idle &w, int revents);
		1764
		1765	myclass ();
		1766	}
		1767
		1768	myclass::myclass (int fd)
		1769	: io (this, &myclass::io_cb),
		1770	idle (this, &myclass::idle_cb)
		1771	{
		1772	io.start (fd, ev::READ);
		1773	}
		1774
		1775
		1776
		1777
		1778	</pre>
		1779
1309	</div>	1780	</div>
1310	<h1 id="AUTHOR">AUTHOR</h1><p><a href="#TOP" class="toplink">Top</a></p>	1781	<h1 id="MACRO_MAGIC">MACRO MAGIC</h1>
		1782	<div id="MACRO_MAGIC_CONTENT">
		1783	<p>Libev can be compiled with a variety of options, the most fundemantal is
		1784	<code>EV_MULTIPLICITY</code>. This option determines wether (most) functions and
		1785	callbacks have an initial <code>struct ev_loop *</code> argument.</p>
		1786	<p>To make it easier to write programs that cope with either variant, the
		1787	following macros are defined:</p>
		1788	<dl>
		1789	<dt><code>EV_A</code>, <code>EV_A_</code></dt>
		1790	<dd>
		1791	<p>This provides the loop <i>argument</i> for functions, if one is required ("ev
		1792	loop argument"). The <code>EV_A</code> form is used when this is the sole argument,
		1793	<code>EV_A_</code> is used when other arguments are following. Example:</p>
		1794	<pre> ev_unref (EV_A);
		1795	ev_timer_add (EV_A_ watcher);
		1796	ev_loop (EV_A_ 0);
		1797
		1798	</pre>
		1799	<p>It assumes the variable <code>loop</code> of type <code>struct ev_loop *</code> is in scope,
		1800	which is often provided by the following macro.</p>
		1801	</dd>
		1802	<dt><code>EV_P</code>, <code>EV_P_</code></dt>
		1803	<dd>
		1804	<p>This provides the loop <i>parameter</i> for functions, if one is required ("ev
		1805	loop parameter"). The <code>EV_P</code> form is used when this is the sole parameter,
		1806	<code>EV_P_</code> is used when other parameters are following. Example:</p>
		1807	<pre> // this is how ev_unref is being declared
		1808	static void ev_unref (EV_P);
		1809
		1810	// this is how you can declare your typical callback
		1811	static void cb (EV_P_ ev_timer *w, int revents)
		1812
		1813	</pre>
		1814	<p>It declares a parameter <code>loop</code> of type <code>struct ev_loop *</code>, quite
		1815	suitable for use with <code>EV_A</code>.</p>
		1816	</dd>
		1817	<dt><code>EV_DEFAULT</code>, <code>EV_DEFAULT_</code></dt>
		1818	<dd>
		1819	<p>Similar to the other two macros, this gives you the value of the default
		1820	loop, if multiple loops are supported ("ev loop default").</p>
		1821	</dd>
		1822	</dl>
		1823	<p>Example: Declare and initialise a check watcher, working regardless of
		1824	wether multiple loops are supported or not.</p>
		1825	<pre> static void
		1826	check_cb (EV_P_ ev_timer *w, int revents)
		1827	{
		1828	ev_check_stop (EV_A_ w);
		1829	}
		1830
		1831	ev_check check;
		1832	ev_check_init (&check, check_cb);
		1833	ev_check_start (EV_DEFAULT_ &check);
		1834	ev_loop (EV_DEFAULT_ 0);
		1835
		1836
		1837
		1838
		1839	</pre>
		1840
		1841	</div>
		1842	<h1 id="EMBEDDING">EMBEDDING</h1>
		1843	<div id="EMBEDDING_CONTENT">
		1844	<p>Libev can (and often is) directly embedded into host
		1845	applications. Examples of applications that embed it include the Deliantra
		1846	Game Server, the EV perl module, the GNU Virtual Private Ethernet (gvpe)
		1847	and rxvt-unicode.</p>
		1848	<p>The goal is to enable you to just copy the neecssary files into your
		1849	source directory without having to change even a single line in them, so
		1850	you can easily upgrade by simply copying (or having a checked-out copy of
		1851	libev somewhere in your source tree).</p>
		1852
		1853	</div>
		1854	<h2 id="FILESETS">FILESETS</h2>
		1855	<div id="FILESETS_CONTENT">
		1856	<p>Depending on what features you need you need to include one or more sets of files
		1857	in your app.</p>
		1858
		1859	</div>
		1860	<h3 id="CORE_EVENT_LOOP">CORE EVENT LOOP</h3>
		1861	<div id="CORE_EVENT_LOOP_CONTENT">
		1862	<p>To include only the libev core (all the <code>ev_*</code> functions), with manual
		1863	configuration (no autoconf):</p>
		1864	<pre> #define EV_STANDALONE 1
		1865	#include "ev.c"
		1866
		1867	</pre>
		1868	<p>This will automatically include <cite>ev.h</cite>, too, and should be done in a
		1869	single C source file only to provide the function implementations. To use
		1870	it, do the same for <cite>ev.h</cite> in all files wishing to use this API (best
		1871	done by writing a wrapper around <cite>ev.h</cite> that you can include instead and
		1872	where you can put other configuration options):</p>
		1873	<pre> #define EV_STANDALONE 1
		1874	#include "ev.h"
		1875
		1876	</pre>
		1877	<p>Both header files and implementation files can be compiled with a C++
		1878	compiler (at least, thats a stated goal, and breakage will be treated
		1879	as a bug).</p>
		1880	<p>You need the following files in your source tree, or in a directory
		1881	in your include path (e.g. in libev/ when using -Ilibev):</p>
		1882	<pre> ev.h
		1883	ev.c
		1884	ev_vars.h
		1885	ev_wrap.h
		1886
		1887	ev_win32.c required on win32 platforms only
		1888
		1889	ev_select.c only when select backend is enabled (which is by default)
		1890	ev_poll.c only when poll backend is enabled (disabled by default)
		1891	ev_epoll.c only when the epoll backend is enabled (disabled by default)
		1892	ev_kqueue.c only when the kqueue backend is enabled (disabled by default)
		1893	ev_port.c only when the solaris port backend is enabled (disabled by default)
		1894
		1895	</pre>
		1896	<p><cite>ev.c</cite> includes the backend files directly when enabled, so you only need
		1897	to compile this single file.</p>
		1898
		1899	</div>
		1900	<h3 id="LIBEVENT_COMPATIBILITY_API">LIBEVENT COMPATIBILITY API</h3>
		1901	<div id="LIBEVENT_COMPATIBILITY_API_CONTENT">
		1902	<p>To include the libevent compatibility API, also include:</p>
		1903	<pre> #include "event.c"
		1904
		1905	</pre>
		1906	<p>in the file including <cite>ev.c</cite>, and:</p>
		1907	<pre> #include "event.h"
		1908
		1909	</pre>
		1910	<p>in the files that want to use the libevent API. This also includes <cite>ev.h</cite>.</p>
		1911	<p>You need the following additional files for this:</p>
		1912	<pre> event.h
		1913	event.c
		1914
		1915	</pre>
		1916
		1917	</div>
		1918	<h3 id="AUTOCONF_SUPPORT">AUTOCONF SUPPORT</h3>
		1919	<div id="AUTOCONF_SUPPORT_CONTENT">
		1920	<p>Instead of using <code>EV_STANDALONE=1</code> and providing your config in
		1921	whatever way you want, you can also <code>m4_include([libev.m4])</code> in your
		1922	<cite>configure.ac</cite> and leave <code>EV_STANDALONE</code> undefined. <cite>ev.c</cite> will then
		1923	include <cite>config.h</cite> and configure itself accordingly.</p>
		1924	<p>For this of course you need the m4 file:</p>
		1925	<pre> libev.m4
		1926
		1927	</pre>
		1928
		1929	</div>
		1930	<h2 id="PREPROCESSOR_SYMBOLS_MACROS">PREPROCESSOR SYMBOLS/MACROS</h2>
		1931	<div id="PREPROCESSOR_SYMBOLS_MACROS_CONTENT">
		1932	<p>Libev can be configured via a variety of preprocessor symbols you have to define
		1933	before including any of its files. The default is not to build for multiplicity
		1934	and only include the select backend.</p>
		1935	<dl>
		1936	<dt>EV_STANDALONE</dt>
		1937	<dd>
		1938	<p>Must always be <code>1</code> if you do not use autoconf configuration, which
		1939	keeps libev from including <cite>config.h</cite>, and it also defines dummy
		1940	implementations for some libevent functions (such as logging, which is not
		1941	supported). It will also not define any of the structs usually found in
		1942	<cite>event.h</cite> that are not directly supported by the libev core alone.</p>
		1943	</dd>
		1944	<dt>EV_USE_MONOTONIC</dt>
		1945	<dd>
		1946	<p>If defined to be <code>1</code>, libev will try to detect the availability of the
		1947	monotonic clock option at both compiletime and runtime. Otherwise no use
		1948	of the monotonic clock option will be attempted. If you enable this, you
		1949	usually have to link against librt or something similar. Enabling it when
		1950	the functionality isn't available is safe, though, althoguh you have
		1951	to make sure you link against any libraries where the <code>clock_gettime</code>
		1952	function is hiding in (often <cite>-lrt</cite>).</p>
		1953	</dd>
		1954	<dt>EV_USE_REALTIME</dt>
		1955	<dd>
		1956	<p>If defined to be <code>1</code>, libev will try to detect the availability of the
		1957	realtime clock option at compiletime (and assume its availability at
		1958	runtime if successful). Otherwise no use of the realtime clock option will
		1959	be attempted. This effectively replaces <code>gettimeofday</code> by <code>clock_get
		1960	(CLOCK_REALTIME, ...)</code> and will not normally affect correctness. See tzhe note about libraries
		1961	in the description of <code>EV_USE_MONOTONIC</code>, though.</p>
		1962	</dd>
		1963	<dt>EV_USE_SELECT</dt>
		1964	<dd>
		1965	<p>If undefined or defined to be <code>1</code>, libev will compile in support for the
		1966	<code>select</code>(2) backend. No attempt at autodetection will be done: if no
		1967	other method takes over, select will be it. Otherwise the select backend
		1968	will not be compiled in.</p>
		1969	</dd>
		1970	<dt>EV_SELECT_USE_FD_SET</dt>
		1971	<dd>
		1972	<p>If defined to <code>1</code>, then the select backend will use the system <code>fd_set</code>
		1973	structure. This is useful if libev doesn't compile due to a missing
		1974	<code>NFDBITS</code> or <code>fd_mask</code> definition or it misguesses the bitset layout on
		1975	exotic systems. This usually limits the range of file descriptors to some
		1976	low limit such as 1024 or might have other limitations (winsocket only
		1977	allows 64 sockets). The <code>FD_SETSIZE</code> macro, set before compilation, might
		1978	influence the size of the <code>fd_set</code> used.</p>
		1979	</dd>
		1980	<dt>EV_SELECT_IS_WINSOCKET</dt>
		1981	<dd>
		1982	<p>When defined to <code>1</code>, the select backend will assume that
		1983	select/socket/connect etc. don't understand file descriptors but
		1984	wants osf handles on win32 (this is the case when the select to
		1985	be used is the winsock select). This means that it will call
		1986	<code>_get_osfhandle</code> on the fd to convert it to an OS handle. Otherwise,
		1987	it is assumed that all these functions actually work on fds, even
		1988	on win32. Should not be defined on non-win32 platforms.</p>
		1989	</dd>
		1990	<dt>EV_USE_POLL</dt>
		1991	<dd>
		1992	<p>If defined to be <code>1</code>, libev will compile in support for the <code>poll</code>(2)
		1993	backend. Otherwise it will be enabled on non-win32 platforms. It
		1994	takes precedence over select.</p>
		1995	</dd>
		1996	<dt>EV_USE_EPOLL</dt>
		1997	<dd>
		1998	<p>If defined to be <code>1</code>, libev will compile in support for the Linux
		1999	<code>epoll</code>(7) backend. Its availability will be detected at runtime,
		2000	otherwise another method will be used as fallback. This is the
		2001	preferred backend for GNU/Linux systems.</p>
		2002	</dd>
		2003	<dt>EV_USE_KQUEUE</dt>
		2004	<dd>
		2005	<p>If defined to be <code>1</code>, libev will compile in support for the BSD style
		2006	<code>kqueue</code>(2) backend. Its actual availability will be detected at runtime,
		2007	otherwise another method will be used as fallback. This is the preferred
		2008	backend for BSD and BSD-like systems, although on most BSDs kqueue only
		2009	supports some types of fds correctly (the only platform we found that
		2010	supports ptys for example was NetBSD), so kqueue might be compiled in, but
		2011	not be used unless explicitly requested. The best way to use it is to find
		2012	out whether kqueue supports your type of fd properly and use an embedded
		2013	kqueue loop.</p>
		2014	</dd>
		2015	<dt>EV_USE_PORT</dt>
		2016	<dd>
		2017	<p>If defined to be <code>1</code>, libev will compile in support for the Solaris
		2018	10 port style backend. Its availability will be detected at runtime,
		2019	otherwise another method will be used as fallback. This is the preferred
		2020	backend for Solaris 10 systems.</p>
		2021	</dd>
		2022	<dt>EV_USE_DEVPOLL</dt>
		2023	<dd>
		2024	<p>reserved for future expansion, works like the USE symbols above.</p>
		2025	</dd>
		2026	<dt>EV_USE_INOTIFY</dt>
		2027	<dd>
		2028	<p>If defined to be <code>1</code>, libev will compile in support for the Linux inotify
		2029	interface to speed up <code>ev_stat</code> watchers. Its actual availability will
		2030	be detected at runtime.</p>
		2031	</dd>
		2032	<dt>EV_H</dt>
		2033	<dd>
		2034	<p>The name of the <cite>ev.h</cite> header file used to include it. The default if
		2035	undefined is <code><ev.h></code> in <cite>event.h</cite> and <code>"ev.h"</code> in <cite>ev.c</cite>. This
		2036	can be used to virtually rename the <cite>ev.h</cite> header file in case of conflicts.</p>
		2037	</dd>
		2038	<dt>EV_CONFIG_H</dt>
		2039	<dd>
		2040	<p>If <code>EV_STANDALONE</code> isn't <code>1</code>, this variable can be used to override
		2041	<cite>ev.c</cite>'s idea of where to find the <cite>config.h</cite> file, similarly to
		2042	<code>EV_H</code>, above.</p>
		2043	</dd>
		2044	<dt>EV_EVENT_H</dt>
		2045	<dd>
		2046	<p>Similarly to <code>EV_H</code>, this macro can be used to override <cite>event.c</cite>'s idea
		2047	of how the <cite>event.h</cite> header can be found.</p>
		2048	</dd>
		2049	<dt>EV_PROTOTYPES</dt>
		2050	<dd>
		2051	<p>If defined to be <code>0</code>, then <cite>ev.h</cite> will not define any function
		2052	prototypes, but still define all the structs and other symbols. This is
		2053	occasionally useful if you want to provide your own wrapper functions
		2054	around libev functions.</p>
		2055	</dd>
		2056	<dt>EV_MULTIPLICITY</dt>
		2057	<dd>
		2058	<p>If undefined or defined to <code>1</code>, then all event-loop-specific functions
		2059	will have the <code>struct ev_loop *</code> as first argument, and you can create
		2060	additional independent event loops. Otherwise there will be no support
		2061	for multiple event loops and there is no first event loop pointer
		2062	argument. Instead, all functions act on the single default loop.</p>
		2063	</dd>
		2064	<dt>EV_PERIODIC_ENABLE</dt>
		2065	<dd>
		2066	<p>If undefined or defined to be <code>1</code>, then periodic timers are supported. If
		2067	defined to be <code>0</code>, then they are not. Disabling them saves a few kB of
		2068	code.</p>
		2069	</dd>
		2070	<dt>EV_EMBED_ENABLE</dt>
		2071	<dd>
		2072	<p>If undefined or defined to be <code>1</code>, then embed watchers are supported. If
		2073	defined to be <code>0</code>, then they are not.</p>
		2074	</dd>
		2075	<dt>EV_STAT_ENABLE</dt>
		2076	<dd>
		2077	<p>If undefined or defined to be <code>1</code>, then stat watchers are supported. If
		2078	defined to be <code>0</code>, then they are not.</p>
		2079	</dd>
		2080	<dt>EV_FORK_ENABLE</dt>
		2081	<dd>
		2082	<p>If undefined or defined to be <code>1</code>, then fork watchers are supported. If
		2083	defined to be <code>0</code>, then they are not.</p>
		2084	</dd>
		2085	<dt>EV_MINIMAL</dt>
		2086	<dd>
		2087	<p>If you need to shave off some kilobytes of code at the expense of some
		2088	speed, define this symbol to <code>1</code>. Currently only used for gcc to override
		2089	some inlining decisions, saves roughly 30% codesize of amd64.</p>
		2090	</dd>
		2091	<dt>EV_PID_HASHSIZE</dt>
		2092	<dd>
		2093	<p><code>ev_child</code> watchers use a small hash table to distribute workload by
		2094	pid. The default size is <code>16</code> (or <code>1</code> with <code>EV_MINIMAL</code>), usually more
		2095	than enough. If you need to manage thousands of children you might want to
		2096	increase this value (<i>must</i> be a power of two).</p>
		2097	</dd>
		2098	<dt>EV_INOTIFY_HASHSIZE</dt>
		2099	<dd>
		2100	<p><code>ev_staz</code> watchers use a small hash table to distribute workload by
		2101	inotify watch id. The default size is <code>16</code> (or <code>1</code> with <code>EV_MINIMAL</code>),
		2102	usually more than enough. If you need to manage thousands of <code>ev_stat</code>
		2103	watchers you might want to increase this value (<i>must</i> be a power of
		2104	two).</p>
		2105	</dd>
		2106	<dt>EV_COMMON</dt>
		2107	<dd>
		2108	<p>By default, all watchers have a <code>void *data</code> member. By redefining
		2109	this macro to a something else you can include more and other types of
		2110	members. You have to define it each time you include one of the files,
		2111	though, and it must be identical each time.</p>
		2112	<p>For example, the perl EV module uses something like this:</p>
		2113	<pre> #define EV_COMMON \
		2114	SV self; / contains this struct */ \
		2115	SV cb_sv, fh /* note no trailing ";" */
		2116
		2117	</pre>
		2118	</dd>
		2119	<dt>EV_CB_DECLARE (type)</dt>
		2120	<dt>EV_CB_INVOKE (watcher, revents)</dt>
		2121	<dt>ev_set_cb (ev, cb)</dt>
		2122	<dd>
		2123	<p>Can be used to change the callback member declaration in each watcher,
		2124	and the way callbacks are invoked and set. Must expand to a struct member
		2125	definition and a statement, respectively. See the <cite>ev.v</cite> header file for
		2126	their default definitions. One possible use for overriding these is to
		2127	avoid the <code>struct ev_loop *</code> as first argument in all cases, or to use
		2128	method calls instead of plain function calls in C++.</p>
		2129
		2130	</div>
		2131	<h2 id="EXAMPLES">EXAMPLES</h2>
		2132	<div id="EXAMPLES_CONTENT">
		2133	<p>For a real-world example of a program the includes libev
		2134	verbatim, you can have a look at the EV perl module
		2135	(<a href="http://software.schmorp.de/pkg/EV.html">http://software.schmorp.de/pkg/EV.html</a>). It has the libev files in
		2136	the <cite>libev/</cite> subdirectory and includes them in the <cite>EV/EVAPI.h</cite> (public
		2137	interface) and <cite>EV.xs</cite> (implementation) files. Only the <cite>EV.xs</cite> file
		2138	will be compiled. It is pretty complex because it provides its own header
		2139	file.</p>
		2140	<p>The usage in rxvt-unicode is simpler. It has a <cite>ev_cpp.h</cite> header file
		2141	that everybody includes and which overrides some autoconf choices:</p>
		2142	<pre> #define EV_USE_POLL 0
		2143	#define EV_MULTIPLICITY 0
		2144	#define EV_PERIODICS 0
		2145	#define EV_CONFIG_H <config.h>
		2146
		2147	#include "ev++.h"
		2148
		2149	</pre>
		2150	<p>And a <cite>ev_cpp.C</cite> implementation file that contains libev proper and is compiled:</p>
		2151	<pre> #include "ev_cpp.h"
		2152	#include "ev.c"
		2153
		2154
		2155
		2156
		2157	</pre>
		2158
		2159	</div>
		2160	<h1 id="COMPLEXITIES">COMPLEXITIES</h1>
		2161	<div id="COMPLEXITIES_CONTENT">
		2162	<p>In this section the complexities of (many of) the algorithms used inside
		2163	libev will be explained. For complexity discussions about backends see the
		2164	documentation for <code>ev_default_init</code>.</p>
		2165	<p>
		2166	<dl>
		2167	<dt>Starting and stopping timer/periodic watchers: O(log skipped_other_timers)</dt>
		2168	<dt>Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)</dt>
		2169	<dt>Starting io/check/prepare/idle/signal/child watchers: O(1)</dt>
		2170	<dt>Stopping check/prepare/idle watchers: O(1)</dt>
		2171	<dt>Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))</dt>
		2172	<dt>Finding the next timer per loop iteration: O(1)</dt>
		2173	<dt>Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)</dt>
		2174	<dt>Activating one watcher: O(1)</dt>
		2175	</dl>
		2176	</p>
		2177
		2178
		2179
		2180
		2181
		2182	</div>
		2183	<h1 id="AUTHOR">AUTHOR</h1>
1311	<div id="AUTHOR_CONTENT">	2184	<div id="AUTHOR_CONTENT">
1312	<p>Marc Lehmann <libev@schmorp.de>.</p>	2185	<p>Marc Lehmann <libev@schmorp.de>.</p>
1313		2186
1314	</div>	2187	</div>
1315	</div></body>	2188	</div></body>
1316	</html>	2189	</html>

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Revision 1.58 by root, Wed Nov 28 11:31:34 2007 UTC