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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 21:14:27 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 -->
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>
… …
59<li><a href="#AUTHOR">AUTHOR</a> 60<li><a href="#AUTHOR">AUTHOR</a>
60</li> 61</li>
61</ul><hr /> 62</ul><hr />
62<!-- INDEX END --> 63<!-- INDEX END -->
63 64
64<h1 id="NAME">NAME</h1><p><a href="#TOP" class="toplink">Top</a></p> 65<h1 id="NAME">NAME</h1>
65<div id="NAME_CONTENT"> 66<div id="NAME_CONTENT">
66<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>
67 68
68</div> 69</div>
69<h1 id="SYNOPSIS">SYNOPSIS</h1><p><a href="#TOP" class="toplink">Top</a></p> 70<h1 id="SYNOPSIS">SYNOPSIS</h1>
70<div id="SYNOPSIS_CONTENT"> 71<div id="SYNOPSIS_CONTENT">
71<pre> /* this is the only header you need */
72 #include &lt;ev.h&gt; 72<pre> #include &lt;ev.h&gt;
73 73
74 /* what follows is a fully working example program */ 74</pre>
75
76</div>
77<h1 id="EXAMPLE_PROGRAM">EXAMPLE PROGRAM</h1>
78<div id="EXAMPLE_PROGRAM_CONTENT">
79<pre> #include &lt;ev.h&gt;
80
75 ev_io stdin_watcher; 81 ev_io stdin_watcher;
76 ev_timer timeout_watcher; 82 ev_timer timeout_watcher;
77 83
78 /* called when data readable on stdin */ 84 /* called when data readable on stdin */
79 static void 85 static void
… …
111 } 117 }
112 118
113</pre> 119</pre>
114 120
115</div> 121</div>
116<h1 id="DESCRIPTION">DESCRIPTION</h1><p><a href="#TOP" class="toplink">Top</a></p> 122<h1 id="DESCRIPTION">DESCRIPTION</h1>
117<div id="DESCRIPTION_CONTENT"> 123<div id="DESCRIPTION_CONTENT">
118<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
119file descriptor being readable or a timeout occuring), and it will manage 125file descriptor being readable or a timeout occuring), and it will manage
120these event sources and provide your program with events.</p> 126these event sources and provide your program with events.</p>
121<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
… …
125watchers</i>, which are relatively small C structures you initialise with the 131watchers</i>, which are relatively small C structures you initialise with the
126details 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
127watcher.</p> 133watcher.</p>
128 134
129</div> 135</div>
130<h1 id="FEATURES">FEATURES</h1><p><a href="#TOP" class="toplink">Top</a></p> 136<h1 id="FEATURES">FEATURES</h1>
131<div id="FEATURES_CONTENT"> 137<div id="FEATURES_CONTENT">
132<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
133kqueue mechanisms for file descriptor events, relative timers, absolute 139bsd-specific <code>kqueue</code> and the solaris-specific event port mechanisms
134timers with customised rescheduling, signal events, process status change 140for file descriptor events (<code>ev_io</code>), relative timers (<code>ev_timer</code>),
135events (related to SIGCHLD), and event watchers dealing with the event 141absolute timers with customised rescheduling (<code>ev_periodic</code>), synchronous
136loop mechanism itself (idle, prepare and check watchers). It also is quite 142signals (<code>ev_signal</code>), process status change events (<code>ev_child</code>), and
143event watchers dealing with the event loop mechanism itself (<code>ev_idle</code>,
144<code>ev_embed</code>, <code>ev_prepare</code> and <code>ev_check</code> watchers) as well as
145file watchers (<code>ev_stat</code>) and even limited support for fork events
146(<code>ev_fork</code>).</p>
147<p>It also is quite fast (see this
137fast (see this <a href="http://libev.schmorp.de/bench.html">benchmark</a> comparing 148<a href="http://libev.schmorp.de/bench.html">benchmark</a> comparing it to libevent
138it to libevent for example).</p> 149for example).</p>
139 150
140</div> 151</div>
141<h1 id="CONVENTIONS">CONVENTIONS</h1><p><a href="#TOP" class="toplink">Top</a></p> 152<h1 id="CONVENTIONS">CONVENTIONS</h1>
142<div id="CONVENTIONS_CONTENT"> 153<div id="CONVENTIONS_CONTENT">
143<p>Libev is very configurable. In this manual the default configuration 154<p>Libev is very configurable. In this manual the default configuration will
144will be described, which supports multiple event loops. For more info 155be described, which supports multiple event loops. For more info about
145about various configuration options please have a look at the file 156various configuration options please have a look at <strong>EMBED</strong> section in
146<cite>README.embed</cite> in the libev distribution. If libev was configured without 157this manual. If libev was configured without support for multiple event
147support for multiple event loops, then all functions taking an initial 158loops, then all functions taking an initial argument of name <code>loop</code>
148argument of name <code>loop</code> (which is always of type <code>struct ev_loop *</code>) 159(which is always of type <code>struct ev_loop *</code>) will not have this argument.</p>
149will not have this argument.</p>
150 160
151</div> 161</div>
152<h1 id="TIME_REPRESENTATION">TIME REPRESENTATION</h1><p><a href="#TOP" class="toplink">Top</a></p> 162<h1 id="TIME_REPRESENTATION">TIME REPRESENTATION</h1>
153<div id="TIME_REPRESENTATION_CONTENT"> 163<div id="TIME_REPRESENTATION_CONTENT">
154<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
155(fractional) number of seconds since the (POSIX) epoch (somewhere near 165(fractional) number of seconds since the (POSIX) epoch (somewhere near
156the 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
157called <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
158to 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
159it, you should treat it as such.</p> 169it, you should treat it as such.</p>
160 170
161</div> 171</div>
162<h1 id="GLOBAL_FUNCTIONS">GLOBAL FUNCTIONS</h1><p><a href="#TOP" class="toplink">Top</a></p> 172<h1 id="GLOBAL_FUNCTIONS">GLOBAL FUNCTIONS</h1>
163<div id="GLOBAL_FUNCTIONS_CONTENT"> 173<div id="GLOBAL_FUNCTIONS_CONTENT">
164<p>These functions can be called anytime, even before initialising the 174<p>These functions can be called anytime, even before initialising the
165library in any way.</p> 175library in any way.</p>
166<dl> 176<dl>
167 <dt>ev_tstamp ev_time ()</dt> 177 <dt>ev_tstamp ev_time ()</dt>
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180version of the library your program was compiled against.</p> 190version of the library your program was compiled against.</p>
181 <p>Usually, it's a good idea to terminate if the major versions mismatch, 191 <p>Usually, it's a good idea to terminate if the major versions mismatch,
182as this indicates an incompatible change. Minor versions are usually 192as this indicates an incompatible change. Minor versions are usually
183compatible to older versions, so a larger minor version alone is usually 193compatible to older versions, so a larger minor version alone is usually
184not a problem.</p> 194not a problem.</p>
185 <p>Example: make sure we haven't accidentally been linked against the wrong 195 <p>Example: Make sure we haven't accidentally been linked against the wrong
186version:</p> 196version.</p>
187<pre> assert ((&quot;libev version mismatch&quot;, 197<pre> assert ((&quot;libev version mismatch&quot;,
188 ev_version_major () == EV_VERSION_MAJOR 198 ev_version_major () == EV_VERSION_MAJOR
189 &amp;&amp; ev_version_minor () &gt;= EV_VERSION_MINOR)); 199 &amp;&amp; ev_version_minor () &gt;= EV_VERSION_MINOR));
190 200
191</pre> 201</pre>
… …
229allocated, the library might abort or take some potentially destructive 239allocated, the library might abort or take some potentially destructive
230action. The default is your system realloc function.</p> 240action. The default is your system realloc function.</p>
231 <p>You could override this function in high-availability programs to, say, 241 <p>You could override this function in high-availability programs to, say,
232free some memory if it cannot allocate memory, to use a special allocator, 242free some memory if it cannot allocate memory, to use a special allocator,
233or even to sleep a while and retry until some memory is available.</p> 243or even to sleep a while and retry until some memory is available.</p>
234 <p>Example: replace the libev allocator with one that waits a bit and then 244 <p>Example: Replace the libev allocator with one that waits a bit and then
235retries: better than mine).</p> 245retries).</p>
236<pre> static void * 246<pre> static void *
237 persistent_realloc (void *ptr, size_t size) 247 persistent_realloc (void *ptr, size_t size)
238 { 248 {
239 for (;;) 249 for (;;)
240 { 250 {
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259indicating the system call or subsystem causing the problem. If this 269indicating the system call or subsystem causing the problem. If this
260callback is set, then libev will expect it to remedy the sitution, no 270callback is set, then libev will expect it to remedy the sitution, no
261matter what, when it returns. That is, libev will generally retry the 271matter what, when it returns. That is, libev will generally retry the
262requested operation, or, if the condition doesn't go away, do bad stuff 272requested operation, or, if the condition doesn't go away, do bad stuff
263(such as abort).</p> 273(such as abort).</p>
264 <p>Example: do the same thing as libev does internally:</p> 274 <p>Example: This is basically the same thing that libev does internally, too.</p>
265<pre> static void 275<pre> static void
266 fatal_error (const char *msg) 276 fatal_error (const char *msg)
267 { 277 {
268 perror (msg); 278 perror (msg);
269 abort (); 279 abort ();
… …
275</pre> 285</pre>
276 </dd> 286 </dd>
277</dl> 287</dl>
278 288
279</div> 289</div>
280<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>
281<div id="FUNCTIONS_CONTROLLING_THE_EVENT_LOOP-2"> 291<div id="FUNCTIONS_CONTROLLING_THE_EVENT_LOOP-2">
282<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
283types 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
284events, and dynamically created loops which do not.</p> 294events, and dynamically created loops which do not.</p>
285<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
… …
405 <dd> 415 <dd>
406 <p>Similar to <code>ev_default_loop</code>, but always creates a new event loop that is 416 <p>Similar to <code>ev_default_loop</code>, but always creates a new event loop that is
407always distinct from the default loop. Unlike the default loop, it cannot 417always distinct from the default loop. Unlike the default loop, it cannot
408handle signal and child watchers, and attempts to do so will be greeted by 418handle signal and child watchers, and attempts to do so will be greeted by
409undefined behaviour (or a failed assertion if assertions are enabled).</p> 419undefined behaviour (or a failed assertion if assertions are enabled).</p>
410 <p>Example: try to create a event loop that uses epoll and nothing else.</p> 420 <p>Example: Try to create a event loop that uses epoll and nothing else.</p>
411<pre> struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV); 421<pre> struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV);
412 if (!epoller) 422 if (!epoller)
413 fatal (&quot;no epoll found here, maybe it hides under your chair&quot;); 423 fatal (&quot;no epoll found here, maybe it hides under your chair&quot;);
414 424
415</pre> 425</pre>
… …
508 be handled here by queueing them when their watcher gets executed. 518 be handled here by queueing them when their watcher gets executed.
509 - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK 519 - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK
510 were used, return, otherwise continue with step *. 520 were used, return, otherwise continue with step *.
511 521
512</pre> 522</pre>
513 <p>Example: queue some jobs and then loop until no events are outsanding 523 <p>Example: Queue some jobs and then loop until no events are outsanding
514anymore.</p> 524anymore.</p>
515<pre> ... queue jobs here, make sure they register event watchers as long 525<pre> ... queue jobs here, make sure they register event watchers as long
516 ... as they still have work to do (even an idle watcher will do..) 526 ... as they still have work to do (even an idle watcher will do..)
517 ev_loop (my_loop, 0); 527 ev_loop (my_loop, 0);
518 ... jobs done. yeah! 528 ... jobs done. yeah!
… …
537example, libev itself uses this for its internal signal pipe: It is not 547example, libev itself uses this for its internal signal pipe: It is not
538visible to the libev user and should not keep <code>ev_loop</code> from exiting if 548visible to the libev user and should not keep <code>ev_loop</code> from exiting if
539no event watchers registered by it are active. It is also an excellent 549no event watchers registered by it are active. It is also an excellent
540way to do this for generic recurring timers or from within third-party 550way to do this for generic recurring timers or from within third-party
541libraries. Just remember to <i>unref after start</i> and <i>ref before stop</i>.</p> 551libraries. Just remember to <i>unref after start</i> and <i>ref before stop</i>.</p>
542 <p>Example: create a signal watcher, but keep it from keeping <code>ev_loop</code> 552 <p>Example: Create a signal watcher, but keep it from keeping <code>ev_loop</code>
543running when nothing else is active.</p> 553running when nothing else is active.</p>
544<pre> struct dv_signal exitsig; 554<pre> struct ev_signal exitsig;
545 ev_signal_init (&amp;exitsig, sig_cb, SIGINT); 555 ev_signal_init (&amp;exitsig, sig_cb, SIGINT);
546 ev_signal_start (myloop, &amp;exitsig); 556 ev_signal_start (loop, &amp;exitsig);
547 evf_unref (myloop); 557 evf_unref (loop);
548 558
549</pre> 559</pre>
550 <p>Example: for some weird reason, unregister the above signal handler again.</p> 560 <p>Example: For some weird reason, unregister the above signal handler again.</p>
551<pre> ev_ref (myloop); 561<pre> ev_ref (loop);
552 ev_signal_stop (myloop, &amp;exitsig); 562 ev_signal_stop (loop, &amp;exitsig);
553 563
554</pre> 564</pre>
555 </dd> 565 </dd>
556</dl> 566</dl>
557 567
558 568
559 569
560 570
561 571
562</div> 572</div>
563<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>
564<div id="ANATOMY_OF_A_WATCHER_CONTENT"> 574<div id="ANATOMY_OF_A_WATCHER_CONTENT">
565<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
566interest 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
567become 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>
568<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)
… …
731events 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
732is 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
733<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
734libev (e.g. you cnanot <code>free ()</code> it).</p> 744libev (e.g. you cnanot <code>free ()</code> it).</p>
735 </dd> 745 </dd>
736 <dt>callback = ev_cb (ev_TYPE *watcher)</dt> 746 <dt>callback ev_cb (ev_TYPE *watcher)</dt>
737 <dd> 747 <dd>
738 <p>Returns the callback currently set on the watcher.</p> 748 <p>Returns the callback currently set on the watcher.</p>
739 </dd> 749 </dd>
740 <dt>ev_cb_set (ev_TYPE *watcher, callback)</dt> 750 <dt>ev_cb_set (ev_TYPE *watcher, callback)</dt>
741 <dd> 751 <dd>
… …
773 struct my_io *w = (struct my_io *)w_; 783 struct my_io *w = (struct my_io *)w_;
774 ... 784 ...
775 } 785 }
776 786
777</pre> 787</pre>
778<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
779have 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 }
780 798
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;
781 803
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 }
782 810
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 }
783 817
784 818
819
820
821</pre>
822
785</div> 823</div>
786<h1 id="WATCHER_TYPES">WATCHER TYPES</h1><p><a href="#TOP" class="toplink">Top</a></p> 824<h1 id="WATCHER_TYPES">WATCHER TYPES</h1>
787<div id="WATCHER_TYPES_CONTENT"> 825<div id="WATCHER_TYPES_CONTENT">
788<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
789information given in the last section. Any initialisation/set macros, 827information given in the last section. Any initialisation/set macros,
790functions and members specific to the watcher type are explained.</p> 828functions and members specific to the watcher type are explained.</p>
791<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,
… …
851 <dt>int events [read-only]</dt> 889 <dt>int events [read-only]</dt>
852 <dd> 890 <dd>
853 <p>The events being watched.</p> 891 <p>The events being watched.</p>
854 </dd> 892 </dd>
855</dl> 893</dl>
856<p>Example: call <code>stdin_readable_cb</code> when STDIN_FILENO has become, well 894<p>Example: Call <code>stdin_readable_cb</code> when STDIN_FILENO has become, well
857readable, but only once. Since it is likely line-buffered, you could 895readable, but only once. Since it is likely line-buffered, you could
858attempt to read a whole line in the callback:</p> 896attempt to read a whole line in the callback.</p>
859<pre> static void 897<pre> static void
860 stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents) 898 stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents)
861 { 899 {
862 ev_io_stop (loop, w); 900 ev_io_stop (loop, w);
863 .. read from stdin here (or from w-&gt;fd) and haqndle any I/O errors 901 .. read from stdin here (or from w-&gt;fd) and haqndle any I/O errors
… …
946 <p>The current <code>repeat</code> value. Will be used each time the watcher times out 984 <p>The current <code>repeat</code> value. Will be used each time the watcher times out
947or <code>ev_timer_again</code> is called and determines the next timeout (if any), 985or <code>ev_timer_again</code> is called and determines the next timeout (if any),
948which is also when any modifications are taken into account.</p> 986which is also when any modifications are taken into account.</p>
949 </dd> 987 </dd>
950</dl> 988</dl>
951<p>Example: create a timer that fires after 60 seconds.</p> 989<p>Example: Create a timer that fires after 60 seconds.</p>
952<pre> static void 990<pre> static void
953 one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents) 991 one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents)
954 { 992 {
955 .. one minute over, w is actually stopped right here 993 .. one minute over, w is actually stopped right here
956 } 994 }
… …
958 struct ev_timer mytimer; 996 struct ev_timer mytimer;
959 ev_timer_init (&amp;mytimer, one_minute_cb, 60., 0.); 997 ev_timer_init (&amp;mytimer, one_minute_cb, 60., 0.);
960 ev_timer_start (loop, &amp;mytimer); 998 ev_timer_start (loop, &amp;mytimer);
961 999
962</pre> 1000</pre>
963<p>Example: create a timeout timer that times out after 10 seconds of 1001<p>Example: Create a timeout timer that times out after 10 seconds of
964inactivity.</p> 1002inactivity.</p>
965<pre> static void 1003<pre> static void
966 timeout_cb (struct ev_loop *loop, struct ev_timer *w, int revents) 1004 timeout_cb (struct ev_loop *loop, struct ev_timer *w, int revents)
967 { 1005 {
968 .. ten seconds without any activity 1006 .. ten seconds without any activity
… …
1084 <p>The current reschedule callback, or <code>0</code>, if this functionality is 1122 <p>The current reschedule callback, or <code>0</code>, if this functionality is
1085switched off. Can be changed any time, but changes only take effect when 1123switched off. Can be changed any time, but changes only take effect when
1086the periodic timer fires or <code>ev_periodic_again</code> is being called.</p> 1124the periodic timer fires or <code>ev_periodic_again</code> is being called.</p>
1087 </dd> 1125 </dd>
1088</dl> 1126</dl>
1089<p>Example: call a callback every hour, or, more precisely, whenever the 1127<p>Example: Call a callback every hour, or, more precisely, whenever the
1090system clock is divisible by 3600. The callback invocation times have 1128system clock is divisible by 3600. The callback invocation times have
1091potentially a lot of jittering, but good long-term stability.</p> 1129potentially a lot of jittering, but good long-term stability.</p>
1092<pre> static void 1130<pre> static void
1093 clock_cb (struct ev_loop *loop, struct ev_io *w, int revents) 1131 clock_cb (struct ev_loop *loop, struct ev_io *w, int revents)
1094 { 1132 {
… …
1098 struct ev_periodic hourly_tick; 1136 struct ev_periodic hourly_tick;
1099 ev_periodic_init (&amp;hourly_tick, clock_cb, 0., 3600., 0); 1137 ev_periodic_init (&amp;hourly_tick, clock_cb, 0., 3600., 0);
1100 ev_periodic_start (loop, &amp;hourly_tick); 1138 ev_periodic_start (loop, &amp;hourly_tick);
1101 1139
1102</pre> 1140</pre>
1103<p>Example: the same as above, but use a reschedule callback to do it:</p> 1141<p>Example: The same as above, but use a reschedule callback to do it:</p>
1104<pre> #include &lt;math.h&gt; 1142<pre> #include &lt;math.h&gt;
1105 1143
1106 static ev_tstamp 1144 static ev_tstamp
1107 my_scheduler_cb (struct ev_periodic *w, ev_tstamp now) 1145 my_scheduler_cb (struct ev_periodic *w, ev_tstamp now)
1108 { 1146 {
… …
1110 } 1148 }
1111 1149
1112 ev_periodic_init (&amp;hourly_tick, clock_cb, 0., 0., my_scheduler_cb); 1150 ev_periodic_init (&amp;hourly_tick, clock_cb, 0., 0., my_scheduler_cb);
1113 1151
1114</pre> 1152</pre>
1115<p>Example: call a callback every hour, starting now:</p> 1153<p>Example: Call a callback every hour, starting now:</p>
1116<pre> struct ev_periodic hourly_tick; 1154<pre> struct ev_periodic hourly_tick;
1117 ev_periodic_init (&amp;hourly_tick, clock_cb, 1155 ev_periodic_init (&amp;hourly_tick, clock_cb,
1118 fmod (ev_now (loop), 3600.), 3600., 0); 1156 fmod (ev_now (loop), 3600.), 3600., 0);
1119 ev_periodic_start (loop, &amp;hourly_tick); 1157 ev_periodic_start (loop, &amp;hourly_tick);
1120 1158
… …
1181 <dd> 1219 <dd>
1182 <p>The process exit/trace status caused by <code>rpid</code> (see your systems 1220 <p>The process exit/trace status caused by <code>rpid</code> (see your systems
1183<code>waitpid</code> and <code>sys/wait.h</code> documentation for details).</p> 1221<code>waitpid</code> and <code>sys/wait.h</code> documentation for details).</p>
1184 </dd> 1222 </dd>
1185</dl> 1223</dl>
1186<p>Example: try to exit cleanly on SIGINT and SIGTERM.</p> 1224<p>Example: Try to exit cleanly on SIGINT and SIGTERM.</p>
1187<pre> static void 1225<pre> static void
1188 sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) 1226 sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents)
1189 { 1227 {
1190 ev_unloop (loop, EVUNLOOP_ALL); 1228 ev_unloop (loop, EVUNLOOP_ALL);
1191 } 1229 }
… …
1314 <p>Initialises and configures the idle watcher - it has no parameters of any 1352 <p>Initialises and configures the idle watcher - it has no parameters of any
1315kind. There is a <code>ev_idle_set</code> macro, but using it is utterly pointless, 1353kind. There is a <code>ev_idle_set</code> macro, but using it is utterly pointless,
1316believe me.</p> 1354believe me.</p>
1317 </dd> 1355 </dd>
1318</dl> 1356</dl>
1319<p>Example: dynamically allocate an <code>ev_idle</code>, start it, and in the 1357<p>Example: Dynamically allocate an <code>ev_idle</code> watcher, start it, and in the
1320callback, free it. Alos, use no error checking, as usual.</p> 1358callback, free it. Also, use no error checking, as usual.</p>
1321<pre> static void 1359<pre> static void
1322 idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents) 1360 idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents)
1323 { 1361 {
1324 free (w); 1362 free (w);
1325 // now do something you wanted to do when the program has 1363 // now do something you wanted to do when the program has
… …
1550 1588
1551 1589
1552 1590
1553 1591
1554</div> 1592</div>
1555<h1 id="OTHER_FUNCTIONS">OTHER FUNCTIONS</h1><p><a href="#TOP" class="toplink">Top</a></p> 1593<h1 id="OTHER_FUNCTIONS">OTHER FUNCTIONS</h1>
1556<div id="OTHER_FUNCTIONS_CONTENT"> 1594<div id="OTHER_FUNCTIONS_CONTENT">
1557<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>
1558<dl> 1596<dl>
1559 <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>
1560 <dd> 1598 <dd>
… …
1607 1645
1608 1646
1609 1647
1610 1648
1611</div> 1649</div>
1612<h1 id="LIBEVENT_EMULATION">LIBEVENT EMULATION</h1><p><a href="#TOP" class="toplink">Top</a></p> 1650<h1 id="LIBEVENT_EMULATION">LIBEVENT EMULATION</h1>
1613<div id="LIBEVENT_EMULATION_CONTENT"> 1651<div id="LIBEVENT_EMULATION_CONTENT">
1614<p>Libev offers a compatibility emulation layer for libevent. It cannot 1652<p>Libev offers a compatibility emulation layer for libevent. It cannot
1615emulate the internals of libevent, so here are some usage hints:</p> 1653emulate the internals of libevent, so here are some usage hints:</p>
1616<dl> 1654<dl>
1617 <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>
… …
1627 <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
1628to use the libev header file and library.</dt> 1666to use the libev header file and library.</dt>
1629</dl> 1667</dl>
1630 1668
1631</div> 1669</div>
1632<h1 id="C_SUPPORT">C++ SUPPORT</h1><p><a href="#TOP" class="toplink">Top</a></p> 1670<h1 id="C_SUPPORT">C++ SUPPORT</h1>
1633<div id="C_SUPPORT_CONTENT"> 1671<div id="C_SUPPORT_CONTENT">
1634<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
1635you 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
1636the callback model to a model using method callbacks on objects.</p> 1674the callback model to a model using method callbacks on objects.</p>
1637<p>To use it,</p> 1675<p>To use it,</p>
… …
1732 1770
1733 1771
1734</pre> 1772</pre>
1735 1773
1736</div> 1774</div>
1737<h1 id="MACRO_MAGIC">MACRO MAGIC</h1><p><a href="#TOP" class="toplink">Top</a></p> 1775<h1 id="MACRO_MAGIC">MACRO MAGIC</h1>
1738<div id="MACRO_MAGIC_CONTENT"> 1776<div id="MACRO_MAGIC_CONTENT">
1739<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
1740<code>EV_MULTIPLICITY</code>. This option determines wether (most) functions and 1778<code>EV_MULTIPLICITY</code>. This option determines wether (most) functions and
1741callbacks have an initial <code>struct ev_loop *</code> argument.</p> 1779callbacks have an initial <code>struct ev_loop *</code> argument.</p>
1742<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
… …
1793 1831
1794 1832
1795</pre> 1833</pre>
1796 1834
1797</div> 1835</div>
1798<h1 id="EMBEDDING">EMBEDDING</h1><p><a href="#TOP" class="toplink">Top</a></p> 1836<h1 id="EMBEDDING">EMBEDDING</h1>
1799<div id="EMBEDDING_CONTENT"> 1837<div id="EMBEDDING_CONTENT">
1800<p>Libev can (and often is) directly embedded into host 1838<p>Libev can (and often is) directly embedded into host
1801applications. Examples of applications that embed it include the Deliantra 1839applications. Examples of applications that embed it include the Deliantra
1802Game Server, the EV perl module, the GNU Virtual Private Ethernet (gvpe) 1840Game Server, the EV perl module, the GNU Virtual Private Ethernet (gvpe)
1803and rxvt-unicode.</p> 1841and rxvt-unicode.</p>
… …
2097 2135
2098 2136
2099</pre> 2137</pre>
2100 2138
2101</div> 2139</div>
2102<h1 id="COMPLEXITIES">COMPLEXITIES</h1><p><a href="#TOP" class="toplink">Top</a></p> 2140<h1 id="COMPLEXITIES">COMPLEXITIES</h1>
2103<div id="COMPLEXITIES_CONTENT"> 2141<div id="COMPLEXITIES_CONTENT">
2104 <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
2105libev will be explained. For complexity discussions about backends see the 2143libev will be explained. For complexity discussions about backends see the
2106documentation for <code>ev_default_init</code>.</p> 2144documentation for <code>ev_default_init</code>.</p>
2107 <p> 2145 <p>
… …
2120 2158
2121 2159
2122 2160
2123 2161
2124</div> 2162</div>
2125<h1 id="AUTHOR">AUTHOR</h1><p><a href="#TOP" class="toplink">Top</a></p> 2163<h1 id="AUTHOR">AUTHOR</h1>
2126<div id="AUTHOR_CONTENT"> 2164<div id="AUTHOR_CONTENT">
2127 <p>Marc Lehmann &lt;libev@schmorp.de&gt;.</p> 2165 <p>Marc Lehmann &lt;libev@schmorp.de&gt;.</p>
2128 2166
2129</div> 2167</div>
2130</div></body> 2168</div></body>

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