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4<head> 4<head>
5 <title>libev</title> 5 <title>libev</title>
6 <meta name="description" content="Pod documentation for libev" /> 6 <meta name="description" content="Pod documentation for libev" />
7 <meta name="inputfile" content="&lt;standard input&gt;" /> 7 <meta name="inputfile" content="&lt;standard input&gt;" />
8 <meta name="outputfile" content="&lt;standard output&gt;" /> 8 <meta name="outputfile" content="&lt;standard output&gt;" />
9 <meta name="created" content="Tue Nov 27 21:26:46 2007" /> 9 <meta name="created" content="Tue Nov 27 21:38:05 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 -->
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60<li><a href="#AUTHOR">AUTHOR</a> 60<li><a href="#AUTHOR">AUTHOR</a>
61</li> 61</li>
62</ul><hr /> 62</ul><hr />
63<!-- INDEX END --> 63<!-- INDEX END -->
64 64
65<h1 id="NAME">NAME</h1><p><a href="#TOP" class="toplink">Top</a></p> 65<h1 id="NAME">NAME</h1>
66<div id="NAME_CONTENT"> 66<div id="NAME_CONTENT">
67<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>
68 68
69</div> 69</div>
70<h1 id="SYNOPSIS">SYNOPSIS</h1><p><a href="#TOP" class="toplink">Top</a></p> 70<h1 id="SYNOPSIS">SYNOPSIS</h1>
71<div id="SYNOPSIS_CONTENT"> 71<div id="SYNOPSIS_CONTENT">
72<pre> #include &lt;ev.h&gt; 72<pre> #include &lt;ev.h&gt;
73 73
74</pre> 74</pre>
75 75
76</div> 76</div>
77<h1 id="EXAMPLE_PROGRAM">EXAMPLE PROGRAM</h1><p><a href="#TOP" class="toplink">Top</a></p> 77<h1 id="EXAMPLE_PROGRAM">EXAMPLE PROGRAM</h1>
78<div id="EXAMPLE_PROGRAM_CONTENT"> 78<div id="EXAMPLE_PROGRAM_CONTENT">
79<pre> #include &lt;ev.h&gt; 79<pre> #include &lt;ev.h&gt;
80 80
81 ev_io stdin_watcher; 81 ev_io stdin_watcher;
82 ev_timer timeout_watcher; 82 ev_timer timeout_watcher;
… …
117 } 117 }
118 118
119</pre> 119</pre>
120 120
121</div> 121</div>
122<h1 id="DESCRIPTION">DESCRIPTION</h1><p><a href="#TOP" class="toplink">Top</a></p> 122<h1 id="DESCRIPTION">DESCRIPTION</h1>
123<div id="DESCRIPTION_CONTENT"> 123<div id="DESCRIPTION_CONTENT">
124<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
125file descriptor being readable or a timeout occuring), and it will manage 125file descriptor being readable or a timeout occuring), and it will manage
126these event sources and provide your program with events.</p> 126these event sources and provide your program with events.</p>
127<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
… …
131watchers</i>, which are relatively small C structures you initialise with the 131watchers</i>, which are relatively small C structures you initialise with the
132details of the event, and then hand it over to libev by <i>starting</i> the 132details of the event, and then hand it over to libev by <i>starting</i> the
133watcher.</p> 133watcher.</p>
134 134
135</div> 135</div>
136<h1 id="FEATURES">FEATURES</h1><p><a href="#TOP" class="toplink">Top</a></p> 136<h1 id="FEATURES">FEATURES</h1>
137<div id="FEATURES_CONTENT"> 137<div id="FEATURES_CONTENT">
138<p>Libev supports <code>select</code>, <code>poll</code>, the linux-specific <code>epoll</code>, the 138<p>Libev supports <code>select</code>, <code>poll</code>, the linux-specific <code>epoll</code>, the
139bsd-specific <code>kqueue</code> and the solaris-specific event port mechanisms 139bsd-specific <code>kqueue</code> and the solaris-specific event port mechanisms
140for file descriptor events (<code>ev_io</code>), relative timers (<code>ev_timer</code>), 140for file descriptor events (<code>ev_io</code>), relative timers (<code>ev_timer</code>),
141absolute timers with customised rescheduling (<code>ev_periodic</code>), synchronous 141absolute timers with customised rescheduling (<code>ev_periodic</code>), synchronous
… …
147<p>It also is quite fast (see this 147<p>It also is quite fast (see this
148<a href="http://libev.schmorp.de/bench.html">benchmark</a> comparing it to libevent 148<a href="http://libev.schmorp.de/bench.html">benchmark</a> comparing it to libevent
149for example).</p> 149for example).</p>
150 150
151</div> 151</div>
152<h1 id="CONVENTIONS">CONVENTIONS</h1><p><a href="#TOP" class="toplink">Top</a></p> 152<h1 id="CONVENTIONS">CONVENTIONS</h1>
153<div id="CONVENTIONS_CONTENT"> 153<div id="CONVENTIONS_CONTENT">
154<p>Libev is very configurable. In this manual the default configuration will 154<p>Libev is very configurable. In this manual the default configuration will
155be described, which supports multiple event loops. For more info about 155be described, which supports multiple event loops. For more info about
156various configuration options please have a look at <strong>EMBED</strong> section in 156various configuration options please have a look at <strong>EMBED</strong> section in
157this manual. If libev was configured without support for multiple event 157this manual. If libev was configured without support for multiple event
158loops, then all functions taking an initial argument of name <code>loop</code> 158loops, then all functions taking an initial argument of name <code>loop</code>
159(which is always of type <code>struct ev_loop *</code>) will not have this argument.</p> 159(which is always of type <code>struct ev_loop *</code>) will not have this argument.</p>
160 160
161</div> 161</div>
162<h1 id="TIME_REPRESENTATION">TIME REPRESENTATION</h1><p><a href="#TOP" class="toplink">Top</a></p> 162<h1 id="TIME_REPRESENTATION">TIME REPRESENTATION</h1>
163<div id="TIME_REPRESENTATION_CONTENT"> 163<div id="TIME_REPRESENTATION_CONTENT">
164<p>Libev represents time as a single floating point number, representing the 164<p>Libev represents time as a single floating point number, representing the
165(fractional) number of seconds since the (POSIX) epoch (somewhere near 165(fractional) number of seconds since the (POSIX) epoch (somewhere near
166the beginning of 1970, details are complicated, don't ask). This type is 166the beginning of 1970, details are complicated, don't ask). This type is
167called <code>ev_tstamp</code>, which is what you should use too. It usually aliases 167called <code>ev_tstamp</code>, which is what you should use too. It usually aliases
168to the <code>double</code> type in C, and when you need to do any calculations on 168to the <code>double</code> type in C, and when you need to do any calculations on
169it, you should treat it as such.</p> 169it, you should treat it as such.</p>
170 170
171</div> 171</div>
172<h1 id="GLOBAL_FUNCTIONS">GLOBAL FUNCTIONS</h1><p><a href="#TOP" class="toplink">Top</a></p> 172<h1 id="GLOBAL_FUNCTIONS">GLOBAL FUNCTIONS</h1>
173<div id="GLOBAL_FUNCTIONS_CONTENT"> 173<div id="GLOBAL_FUNCTIONS_CONTENT">
174<p>These functions can be called anytime, even before initialising the 174<p>These functions can be called anytime, even before initialising the
175library in any way.</p> 175library in any way.</p>
176<dl> 176<dl>
177 <dt>ev_tstamp ev_time ()</dt> 177 <dt>ev_tstamp ev_time ()</dt>
… …
285</pre> 285</pre>
286 </dd> 286 </dd>
287</dl> 287</dl>
288 288
289</div> 289</div>
290<h1 id="FUNCTIONS_CONTROLLING_THE_EVENT_LOOP">FUNCTIONS CONTROLLING THE EVENT LOOP</h1><p><a href="#TOP" class="toplink">Top</a></p> 290<h1 id="FUNCTIONS_CONTROLLING_THE_EVENT_LOOP">FUNCTIONS CONTROLLING THE EVENT LOOP</h1>
291<div id="FUNCTIONS_CONTROLLING_THE_EVENT_LOOP-2"> 291<div id="FUNCTIONS_CONTROLLING_THE_EVENT_LOOP-2">
292<p>An event loop is described by a <code>struct ev_loop *</code>. The library knows two 292<p>An event loop is described by a <code>struct ev_loop *</code>. The library knows two
293types of such loops, the <i>default</i> loop, which supports signals and child 293types of such loops, the <i>default</i> loop, which supports signals and child
294events, and dynamically created loops which do not.</p> 294events, and dynamically created loops which do not.</p>
295<p>If you use threads, a common model is to run the default event loop 295<p>If you use threads, a common model is to run the default event loop
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568 568
569 569
570 570
571 571
572</div> 572</div>
573<h1 id="ANATOMY_OF_A_WATCHER">ANATOMY OF A WATCHER</h1><p><a href="#TOP" class="toplink">Top</a></p> 573<h1 id="ANATOMY_OF_A_WATCHER">ANATOMY OF A WATCHER</h1>
574<div id="ANATOMY_OF_A_WATCHER_CONTENT"> 574<div id="ANATOMY_OF_A_WATCHER_CONTENT">
575<p>A watcher is a structure that you create and register to record your 575<p>A watcher is a structure that you create and register to record your
576interest in some event. For instance, if you want to wait for STDIN to 576interest in some event. For instance, if you want to wait for STDIN to
577become readable, you would create an <code>ev_io</code> watcher for that:</p> 577become readable, you would create an <code>ev_io</code> watcher for that:</p>
578<pre> static void my_cb (struct ev_loop *loop, struct ev_io *w, int revents) 578<pre> static void my_cb (struct ev_loop *loop, struct ev_io *w, int revents)
… …
741events but its callback has not yet been invoked). As long as a watcher 741events but its callback has not yet been invoked). As long as a watcher
742is pending (but not active) you must not call an init function on it (but 742is pending (but not active) you must not call an init function on it (but
743<code>ev_TYPE_set</code> is safe) and you must make sure the watcher is available to 743<code>ev_TYPE_set</code> is safe) and you must make sure the watcher is available to
744libev (e.g. you cnanot <code>free ()</code> it).</p> 744libev (e.g. you cnanot <code>free ()</code> it).</p>
745 </dd> 745 </dd>
746 <dt>callback = ev_cb (ev_TYPE *watcher)</dt> 746 <dt>callback ev_cb (ev_TYPE *watcher)</dt>
747 <dd> 747 <dd>
748 <p>Returns the callback currently set on the watcher.</p> 748 <p>Returns the callback currently set on the watcher.</p>
749 </dd> 749 </dd>
750 <dt>ev_cb_set (ev_TYPE *watcher, callback)</dt> 750 <dt>ev_cb_set (ev_TYPE *watcher, callback)</dt>
751 <dd> 751 <dd>
… …
783 struct my_io *w = (struct my_io *)w_; 783 struct my_io *w = (struct my_io *)w_;
784 ... 784 ...
785 } 785 }
786 786
787</pre> 787</pre>
788<p>More interesting and less C-conformant ways of catsing your callback type 788<p>More interesting and less C-conformant ways of casting your callback type
789have been omitted....</p> 789instead have been omitted.</p>
790<p>Another common scenario is having some data structure with multiple
791watchers:</p>
792<pre> struct my_biggy
793 {
794 int some_data;
795 ev_timer t1;
796 ev_timer t2;
797 }
790 798
799</pre>
800<p>In this case getting the pointer to <code>my_biggy</code> is a bit more complicated,
801you need to use <code>offsetof</code>:</p>
802<pre> #include &lt;stddef.h&gt;
791 803
804 static void
805 t1_cb (EV_P_ struct ev_timer *w, int revents)
806 {
807 struct my_biggy big = (struct my_biggy *
808 (((char *)w) - offsetof (struct my_biggy, t1));
809 }
792 810
811 static void
812 t2_cb (EV_P_ struct ev_timer *w, int revents)
813 {
814 struct my_biggy big = (struct my_biggy *
815 (((char *)w) - offsetof (struct my_biggy, t2));
816 }
793 817
794 818
819
820
821</pre>
822
795</div> 823</div>
796<h1 id="WATCHER_TYPES">WATCHER TYPES</h1><p><a href="#TOP" class="toplink">Top</a></p> 824<h1 id="WATCHER_TYPES">WATCHER TYPES</h1>
797<div id="WATCHER_TYPES_CONTENT"> 825<div id="WATCHER_TYPES_CONTENT">
798<p>This section describes each watcher in detail, but will not repeat 826<p>This section describes each watcher in detail, but will not repeat
799information given in the last section. Any initialisation/set macros, 827information given in the last section. Any initialisation/set macros,
800functions and members specific to the watcher type are explained.</p> 828functions and members specific to the watcher type are explained.</p>
801<p>Members are additionally marked with either <i>[read-only]</i>, meaning that, 829<p>Members are additionally marked with either <i>[read-only]</i>, meaning that,
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1560 1588
1561 1589
1562 1590
1563 1591
1564</div> 1592</div>
1565<h1 id="OTHER_FUNCTIONS">OTHER FUNCTIONS</h1><p><a href="#TOP" class="toplink">Top</a></p> 1593<h1 id="OTHER_FUNCTIONS">OTHER FUNCTIONS</h1>
1566<div id="OTHER_FUNCTIONS_CONTENT"> 1594<div id="OTHER_FUNCTIONS_CONTENT">
1567<p>There are some other functions of possible interest. Described. Here. Now.</p> 1595<p>There are some other functions of possible interest. Described. Here. Now.</p>
1568<dl> 1596<dl>
1569 <dt>ev_once (loop, int fd, int events, ev_tstamp timeout, callback)</dt> 1597 <dt>ev_once (loop, int fd, int events, ev_tstamp timeout, callback)</dt>
1570 <dd> 1598 <dd>
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1617 1645
1618 1646
1619 1647
1620 1648
1621</div> 1649</div>
1622<h1 id="LIBEVENT_EMULATION">LIBEVENT EMULATION</h1><p><a href="#TOP" class="toplink">Top</a></p> 1650<h1 id="LIBEVENT_EMULATION">LIBEVENT EMULATION</h1>
1623<div id="LIBEVENT_EMULATION_CONTENT"> 1651<div id="LIBEVENT_EMULATION_CONTENT">
1624<p>Libev offers a compatibility emulation layer for libevent. It cannot 1652<p>Libev offers a compatibility emulation layer for libevent. It cannot
1625emulate the internals of libevent, so here are some usage hints:</p> 1653emulate the internals of libevent, so here are some usage hints:</p>
1626<dl> 1654<dl>
1627 <dt>* Use it by including &lt;event.h&gt;, as usual.</dt> 1655 <dt>* Use it by including &lt;event.h&gt;, as usual.</dt>
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1637 <dt>* The libev emulation is <i>not</i> ABI compatible to libevent, you need 1665 <dt>* The libev emulation is <i>not</i> ABI compatible to libevent, you need
1638to use the libev header file and library.</dt> 1666to use the libev header file and library.</dt>
1639</dl> 1667</dl>
1640 1668
1641</div> 1669</div>
1642<h1 id="C_SUPPORT">C++ SUPPORT</h1><p><a href="#TOP" class="toplink">Top</a></p> 1670<h1 id="C_SUPPORT">C++ SUPPORT</h1>
1643<div id="C_SUPPORT_CONTENT"> 1671<div id="C_SUPPORT_CONTENT">
1644<p>Libev comes with some simplistic wrapper classes for C++ that mainly allow 1672<p>Libev comes with some simplistic wrapper classes for C++ that mainly allow
1645you to use some convinience methods to start/stop watchers and also change 1673you to use some convinience methods to start/stop watchers and also change
1646the callback model to a model using method callbacks on objects.</p> 1674the callback model to a model using method callbacks on objects.</p>
1647<p>To use it,</p> 1675<p>To use it,</p>
… …
1742 1770
1743 1771
1744</pre> 1772</pre>
1745 1773
1746</div> 1774</div>
1747<h1 id="MACRO_MAGIC">MACRO MAGIC</h1><p><a href="#TOP" class="toplink">Top</a></p> 1775<h1 id="MACRO_MAGIC">MACRO MAGIC</h1>
1748<div id="MACRO_MAGIC_CONTENT"> 1776<div id="MACRO_MAGIC_CONTENT">
1749<p>Libev can be compiled with a variety of options, the most fundemantal is 1777<p>Libev can be compiled with a variety of options, the most fundemantal is
1750<code>EV_MULTIPLICITY</code>. This option determines wether (most) functions and 1778<code>EV_MULTIPLICITY</code>. This option determines wether (most) functions and
1751callbacks have an initial <code>struct ev_loop *</code> argument.</p> 1779callbacks have an initial <code>struct ev_loop *</code> argument.</p>
1752<p>To make it easier to write programs that cope with either variant, the 1780<p>To make it easier to write programs that cope with either variant, the
… …
1803 1831
1804 1832
1805</pre> 1833</pre>
1806 1834
1807</div> 1835</div>
1808<h1 id="EMBEDDING">EMBEDDING</h1><p><a href="#TOP" class="toplink">Top</a></p> 1836<h1 id="EMBEDDING">EMBEDDING</h1>
1809<div id="EMBEDDING_CONTENT"> 1837<div id="EMBEDDING_CONTENT">
1810<p>Libev can (and often is) directly embedded into host 1838<p>Libev can (and often is) directly embedded into host
1811applications. Examples of applications that embed it include the Deliantra 1839applications. Examples of applications that embed it include the Deliantra
1812Game Server, the EV perl module, the GNU Virtual Private Ethernet (gvpe) 1840Game Server, the EV perl module, the GNU Virtual Private Ethernet (gvpe)
1813and rxvt-unicode.</p> 1841and rxvt-unicode.</p>
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2107 2135
2108 2136
2109</pre> 2137</pre>
2110 2138
2111</div> 2139</div>
2112<h1 id="COMPLEXITIES">COMPLEXITIES</h1><p><a href="#TOP" class="toplink">Top</a></p> 2140<h1 id="COMPLEXITIES">COMPLEXITIES</h1>
2113<div id="COMPLEXITIES_CONTENT"> 2141<div id="COMPLEXITIES_CONTENT">
2114 <p>In this section the complexities of (many of) the algorithms used inside 2142 <p>In this section the complexities of (many of) the algorithms used inside
2115libev will be explained. For complexity discussions about backends see the 2143libev will be explained. For complexity discussions about backends see the
2116documentation for <code>ev_default_init</code>.</p> 2144documentation for <code>ev_default_init</code>.</p>
2117 <p> 2145 <p>
… …
2130 2158
2131 2159
2132 2160
2133 2161
2134</div> 2162</div>
2135<h1 id="AUTHOR">AUTHOR</h1><p><a href="#TOP" class="toplink">Top</a></p> 2163<h1 id="AUTHOR">AUTHOR</h1>
2136<div id="AUTHOR_CONTENT"> 2164<div id="AUTHOR_CONTENT">
2137 <p>Marc Lehmann &lt;libev@schmorp.de&gt;.</p> 2165 <p>Marc Lehmann &lt;libev@schmorp.de&gt;.</p>
2138 2166
2139</div> 2167</div>
2140</div></body> 2168</div></body>

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