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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 09:20:40 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>
… …
35<li><a href="#code_ev_child_code_watch_out_for_pro"><code>ev_child</code> - watch out for process 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>
36<li><a href="#code_ev_stat_code_did_the_file_attri"><code>ev_stat</code> - did the file attributes just change?</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>
37<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>
38<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>
39<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>
40</ul> 42</ul>
41</li> 43</li>
42<li><a href="#OTHER_FUNCTIONS">OTHER FUNCTIONS</a></li> 44<li><a href="#OTHER_FUNCTIONS">OTHER FUNCTIONS</a></li>
43<li><a href="#LIBEVENT_EMULATION">LIBEVENT EMULATION</a></li> 45<li><a href="#LIBEVENT_EMULATION">LIBEVENT EMULATION</a></li>
44<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>
45<li><a href="#EMBEDDING">EMBEDDING</a> 48<li><a href="#EMBEDDING">EMBEDDING</a>
46<ul><li><a href="#FILESETS">FILESETS</a> 49<ul><li><a href="#FILESETS">FILESETS</a>
47<ul><li><a href="#CORE_EVENT_LOOP">CORE EVENT LOOP</a></li> 50<ul><li><a href="#CORE_EVENT_LOOP">CORE EVENT LOOP</a></li>
48<li><a href="#LIBEVENT_COMPATIBILITY_API">LIBEVENT COMPATIBILITY API</a></li> 51<li><a href="#LIBEVENT_COMPATIBILITY_API">LIBEVENT COMPATIBILITY API</a></li>
49<li><a href="#AUTOCONF_SUPPORT">AUTOCONF SUPPORT</a></li> 52<li><a href="#AUTOCONF_SUPPORT">AUTOCONF SUPPORT</a></li>
… …
57<li><a href="#AUTHOR">AUTHOR</a> 60<li><a href="#AUTHOR">AUTHOR</a>
58</li> 61</li>
59</ul><hr /> 62</ul><hr />
60<!-- INDEX END --> 63<!-- INDEX END -->
61 64
62<h1 id="NAME">NAME</h1><p><a href="#TOP" class="toplink">Top</a></p> 65<h1 id="NAME">NAME</h1>
63<div id="NAME_CONTENT"> 66<div id="NAME_CONTENT">
64<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>
65 68
66</div> 69</div>
67<h1 id="SYNOPSIS">SYNOPSIS</h1><p><a href="#TOP" class="toplink">Top</a></p> 70<h1 id="SYNOPSIS">SYNOPSIS</h1>
68<div id="SYNOPSIS_CONTENT"> 71<div id="SYNOPSIS_CONTENT">
69<pre> #include &lt;ev.h&gt; 72<pre> #include &lt;ev.h&gt;
70 73
71</pre> 74</pre>
72 75
73</div> 76</div>
74<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 &lt;ev.h&gt;
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 (&quot;stdin ready&quot;); */
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 (&quot;timeout&quot;); */
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 (&amp;stdin_watcher, stdin_cb, /*STDIN_FILENO*/ 0, EV_READ);
107 ev_io_start (loop, &amp;stdin_watcher);
108
109 /* simple non-repeating 5.5 second timeout */
110 ev_timer_init (&amp;timeout_watcher, timeout_cb, 5.5, 0.);
111 ev_timer_start (loop, &amp;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>
75<div id="DESCRIPTION_CONTENT"> 123<div id="DESCRIPTION_CONTENT">
76<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
77file descriptor being readable or a timeout occuring), and it will manage 125file descriptor being readable or a timeout occuring), and it will manage
78these event sources and provide your program with events.</p> 126these event sources and provide your program with events.</p>
79<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
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83watchers</i>, which are relatively small C structures you initialise with the 131watchers</i>, which are relatively small C structures you initialise with the
84details 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
85watcher.</p> 133watcher.</p>
86 134
87</div> 135</div>
88<h1 id="FEATURES">FEATURES</h1><p><a href="#TOP" class="toplink">Top</a></p> 136<h1 id="FEATURES">FEATURES</h1>
89<div id="FEATURES_CONTENT"> 137<div id="FEATURES_CONTENT">
90<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
91kqueue mechanisms for file descriptor events, relative timers, absolute 139BSD-specific <code>kqueue</code> and the Solaris-specific event port mechanisms
92timers with customised rescheduling, signal events, process status change 140for file descriptor events (<code>ev_io</code>), the Linux <code>inotify</code> interface
93events (related to SIGCHLD), and event watchers dealing with the event 141(for <code>ev_stat</code>), relative timers (<code>ev_timer</code>), absolute timers
94loop mechanism itself (idle, prepare and check watchers). It also is quite 142with customised rescheduling (<code>ev_periodic</code>), synchronous signals
143(<code>ev_signal</code>), process status change events (<code>ev_child</code>), and event
144watchers 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
146file 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
95fast (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
96it to libevent for example).</p> 150for example).</p>
97 151
98</div> 152</div>
99<h1 id="CONVENTIONS">CONVENTIONS</h1><p><a href="#TOP" class="toplink">Top</a></p> 153<h1 id="CONVENTIONS">CONVENTIONS</h1>
100<div id="CONVENTIONS_CONTENT"> 154<div id="CONVENTIONS_CONTENT">
101<p>Libev is very configurable. In this manual the default configuration 155<p>Libev is very configurable. In this manual the default configuration will
102will be described, which supports multiple event loops. For more info 156be described, which supports multiple event loops. For more info about
103about various configuration options please have a look at the file 157various configuration options please have a look at <strong>EMBED</strong> section in
104<cite>README.embed</cite> in the libev distribution. If libev was configured without 158this manual. If libev was configured without support for multiple event
105support for multiple event loops, then all functions taking an initial 159loops, then all functions taking an initial argument of name <code>loop</code>
106argument 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>
107will not have this argument.</p>
108 161
109</div> 162</div>
110<h1 id="TIME_REPRESENTATION">TIME REPRESENTATION</h1><p><a href="#TOP" class="toplink">Top</a></p> 163<h1 id="TIME_REPRESENTATION">TIME REPRESENTATION</h1>
111<div id="TIME_REPRESENTATION_CONTENT"> 164<div id="TIME_REPRESENTATION_CONTENT">
112<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
113(fractional) number of seconds since the (POSIX) epoch (somewhere near 166(fractional) number of seconds since the (POSIX) epoch (somewhere near
114the beginning of 1970, details are complicated, don't ask). This type is 167the beginning of 1970, details are complicated, don't ask). This type is
115called <code>ev_tstamp</code>, which is what you should use too. It usually aliases 168called <code>ev_tstamp</code>, which is what you should use too. It usually aliases
116to the <code>double</code> type in C, and when you need to do any calculations on 169to the <code>double</code> type in C, and when you need to do any calculations on
117it, you should treat it as such.</p> 170it, you should treat it as such.</p>
118 171
119
120
121
122
123</div> 172</div>
124<h1 id="GLOBAL_FUNCTIONS">GLOBAL FUNCTIONS</h1><p><a href="#TOP" class="toplink">Top</a></p> 173<h1 id="GLOBAL_FUNCTIONS">GLOBAL FUNCTIONS</h1>
125<div id="GLOBAL_FUNCTIONS_CONTENT"> 174<div id="GLOBAL_FUNCTIONS_CONTENT">
126<p>These functions can be called anytime, even before initialising the 175<p>These functions can be called anytime, even before initialising the
127library in any way.</p> 176library in any way.</p>
128<dl> 177<dl>
129 <dt>ev_tstamp ev_time ()</dt> 178 <dt>ev_tstamp ev_time ()</dt>
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142version of the library your program was compiled against.</p> 191version of the library your program was compiled against.</p>
143 <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,
144as this indicates an incompatible change. Minor versions are usually 193as this indicates an incompatible change. Minor versions are usually
145compatible to older versions, so a larger minor version alone is usually 194compatible to older versions, so a larger minor version alone is usually
146not a problem.</p> 195not a problem.</p>
147 <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
148version:</p> 197version.</p>
149<pre> assert ((&quot;libev version mismatch&quot;, 198<pre> assert ((&quot;libev version mismatch&quot;,
150 ev_version_major () == EV_VERSION_MAJOR 199 ev_version_major () == EV_VERSION_MAJOR
151 &amp;&amp; ev_version_minor () &gt;= EV_VERSION_MINOR)); 200 &amp;&amp; ev_version_minor () &gt;= EV_VERSION_MINOR));
152 201
153</pre> 202</pre>
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181might be supported on the current system, you would need to look at 230might be supported on the current system, you would need to look at
182<code>ev_embeddable_backends () &amp; ev_supported_backends ()</code>, likewise for 231<code>ev_embeddable_backends () &amp; ev_supported_backends ()</code>, likewise for
183recommended ones.</p> 232recommended ones.</p>
184 <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>
185 </dd> 234 </dd>
186 <dt>ev_set_allocator (void *(*cb)(void *ptr, long size))</dt> 235 <dt>ev_set_allocator (void *(*cb)(void *ptr, size_t size))</dt>
187 <dd> 236 <dd>
188 <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
189realloc C function, the semantics are identical). It is used to allocate 238identical to the realloc C function). It is used to allocate and free
190and free memory (no surprises here). If it returns zero when memory 239memory (no surprises here). If it returns zero when memory needs to be
191needs to be allocated, the library might abort or take some potentially 240allocated, the library might abort or take some potentially destructive
192destructive action. The default is your system realloc function.</p> 241action. The default is your system realloc function.</p>
193 <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,
194free some memory if it cannot allocate memory, to use a special allocator, 243free some memory if it cannot allocate memory, to use a special allocator,
195or even to sleep a while and retry until some memory is available.</p> 244or even to sleep a while and retry until some memory is available.</p>
196 <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
197retries: better than mine).</p> 246retries).</p>
198<pre> static void * 247<pre> static void *
199 persistent_realloc (void *ptr, long size) 248 persistent_realloc (void *ptr, size_t size)
200 { 249 {
201 for (;;) 250 for (;;)
202 { 251 {
203 void *newptr = realloc (ptr, size); 252 void *newptr = realloc (ptr, size);
204 253
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221indicating the system call or subsystem causing the problem. If this 270indicating the system call or subsystem causing the problem. If this
222callback is set, then libev will expect it to remedy the sitution, no 271callback is set, then libev will expect it to remedy the sitution, no
223matter what, when it returns. That is, libev will generally retry the 272matter what, when it returns. That is, libev will generally retry the
224requested operation, or, if the condition doesn't go away, do bad stuff 273requested operation, or, if the condition doesn't go away, do bad stuff
225(such as abort).</p> 274(such as abort).</p>
226 <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>
227<pre> static void 276<pre> static void
228 fatal_error (const char *msg) 277 fatal_error (const char *msg)
229 { 278 {
230 perror (msg); 279 perror (msg);
231 abort (); 280 abort ();
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237</pre> 286</pre>
238 </dd> 287 </dd>
239</dl> 288</dl>
240 289
241</div> 290</div>
242<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>
243<div id="FUNCTIONS_CONTROLLING_THE_EVENT_LOOP-2"> 292<div id="FUNCTIONS_CONTROLLING_THE_EVENT_LOOP-2">
244<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
245types of such loops, the <i>default</i> loop, which supports signals and child 294types of such loops, the <i>default</i> loop, which supports signals and child
246events, and dynamically created loops which do not.</p> 295events, and dynamically created loops which do not.</p>
247<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
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367 <dd> 416 <dd>
368 <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
369always distinct from the default loop. Unlike the default loop, it cannot 418always distinct from the default loop. Unlike the default loop, it cannot
370handle signal and child watchers, and attempts to do so will be greeted by 419handle signal and child watchers, and attempts to do so will be greeted by
371undefined behaviour (or a failed assertion if assertions are enabled).</p> 420undefined behaviour (or a failed assertion if assertions are enabled).</p>
372 <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>
373<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);
374 if (!epoller) 423 if (!epoller)
375 fatal (&quot;no epoll found here, maybe it hides under your chair&quot;); 424 fatal (&quot;no epoll found here, maybe it hides under your chair&quot;);
376 425
377</pre> 426</pre>
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470 be handled here by queueing them when their watcher gets executed. 519 be handled here by queueing them when their watcher gets executed.
471 - 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
472 were used, return, otherwise continue with step *. 521 were used, return, otherwise continue with step *.
473 522
474</pre> 523</pre>
475 <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
476anymore.</p> 525anymore.</p>
477<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
478 ... 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..)
479 ev_loop (my_loop, 0); 528 ev_loop (my_loop, 0);
480 ... jobs done. yeah! 529 ... jobs done. yeah!
… …
499example, libev itself uses this for its internal signal pipe: It is not 548example, libev itself uses this for its internal signal pipe: It is not
500visible to the libev user and should not keep <code>ev_loop</code> from exiting if 549visible to the libev user and should not keep <code>ev_loop</code> from exiting if
501no event watchers registered by it are active. It is also an excellent 550no event watchers registered by it are active. It is also an excellent
502way to do this for generic recurring timers or from within third-party 551way to do this for generic recurring timers or from within third-party
503libraries. Just remember to <i>unref after start</i> and <i>ref before stop</i>.</p> 552libraries. Just remember to <i>unref after start</i> and <i>ref before stop</i>.</p>
504 <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>
505running when nothing else is active.</p> 554running when nothing else is active.</p>
506<pre> struct dv_signal exitsig; 555<pre> struct ev_signal exitsig;
507 ev_signal_init (&amp;exitsig, sig_cb, SIGINT); 556 ev_signal_init (&amp;exitsig, sig_cb, SIGINT);
508 ev_signal_start (myloop, &amp;exitsig); 557 ev_signal_start (loop, &amp;exitsig);
509 evf_unref (myloop); 558 evf_unref (loop);
510 559
511</pre> 560</pre>
512 <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>
513<pre> ev_ref (myloop); 562<pre> ev_ref (loop);
514 ev_signal_stop (myloop, &amp;exitsig); 563 ev_signal_stop (loop, &amp;exitsig);
515 564
516</pre> 565</pre>
517 </dd> 566 </dd>
518</dl> 567</dl>
519 568
520 569
521 570
522 571
523 572
524</div> 573</div>
525<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>
526<div id="ANATOMY_OF_A_WATCHER_CONTENT"> 575<div id="ANATOMY_OF_A_WATCHER_CONTENT">
527<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
528interest in some event. For instance, if you want to wait for STDIN to 577interest in some event. For instance, if you want to wait for STDIN to
529become readable, you would create an <code>ev_io</code> watcher for that:</p> 578become readable, you would create an <code>ev_io</code> watcher for that:</p>
530<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)
… …
606received events. Callbacks of both watcher types can start and stop as 655received events. Callbacks of both watcher types can start and stop as
607many watchers as they want, and all of them will be taken into account 656many watchers as they want, and all of them will be taken into account
608(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
609<code>ev_loop</code> from blocking).</p> 658<code>ev_loop</code> from blocking).</p>
610 </dd> 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>
668 </dd>
611 <dt><code>EV_ERROR</code></dt> 669 <dt><code>EV_ERROR</code></dt>
612 <dd> 670 <dd>
613 <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
614happen because the watcher could not be properly started because libev 672happen because the watcher could not be properly started because libev
615ran out of memory, a file descriptor was found to be closed or any other 673ran out of memory, a file descriptor was found to be closed or any other
… …
684events but its callback has not yet been invoked). As long as a watcher 742events but its callback has not yet been invoked). As long as a watcher
685is pending (but not active) you must not call an init function on it (but 743is pending (but not active) you must not call an init function on it (but
686<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
687libev (e.g. you cnanot <code>free ()</code> it).</p> 745libev (e.g. you cnanot <code>free ()</code> it).</p>
688 </dd> 746 </dd>
689 <dt>callback = ev_cb (ev_TYPE *watcher)</dt> 747 <dt>callback ev_cb (ev_TYPE *watcher)</dt>
690 <dd> 748 <dd>
691 <p>Returns the callback currently set on the watcher.</p> 749 <p>Returns the callback currently set on the watcher.</p>
692 </dd> 750 </dd>
693 <dt>ev_cb_set (ev_TYPE *watcher, callback)</dt> 751 <dt>ev_cb_set (ev_TYPE *watcher, callback)</dt>
694 <dd> 752 <dd>
… …
726 struct my_io *w = (struct my_io *)w_; 784 struct my_io *w = (struct my_io *)w_;
727 ... 785 ...
728 } 786 }
729 787
730</pre> 788</pre>
731<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
732have been omitted....</p> 790instead have been omitted.</p>
791<p>Another common scenario is having some data structure with multiple
792watchers:</p>
793<pre> struct my_biggy
794 {
795 int some_data;
796 ev_timer t1;
797 ev_timer t2;
798 }
733 799
800</pre>
801<p>In this case getting the pointer to <code>my_biggy</code> is a bit more complicated,
802you need to use <code>offsetof</code>:</p>
803<pre> #include &lt;stddef.h&gt;
734 804
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 }
735 811
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 }
736 818
737 819
820
821
822</pre>
823
738</div> 824</div>
739<h1 id="WATCHER_TYPES">WATCHER TYPES</h1><p><a href="#TOP" class="toplink">Top</a></p> 825<h1 id="WATCHER_TYPES">WATCHER TYPES</h1>
740<div id="WATCHER_TYPES_CONTENT"> 826<div id="WATCHER_TYPES_CONTENT">
741<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
742information given in the last section. Any initialisation/set macros, 828information given in the last section. Any initialisation/set macros,
743functions and members specific to the watcher type are explained.</p> 829functions and members specific to the watcher type are explained.</p>
744<p>Members are additionally marked with either <i>[read-only]</i>, meaning that, 830<p>Members are additionally marked with either <i>[read-only]</i>, meaning that,
… …
804 <dt>int events [read-only]</dt> 890 <dt>int events [read-only]</dt>
805 <dd> 891 <dd>
806 <p>The events being watched.</p> 892 <p>The events being watched.</p>
807 </dd> 893 </dd>
808</dl> 894</dl>
809<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
810readable, but only once. Since it is likely line-buffered, you could 896readable, but only once. Since it is likely line-buffered, you could
811attempt to read a whole line in the callback:</p> 897attempt to read a whole line in the callback.</p>
812<pre> static void 898<pre> static void
813 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)
814 { 900 {
815 ev_io_stop (loop, w); 901 ev_io_stop (loop, w);
816 .. read from stdin here (or from w-&gt;fd) and haqndle any I/O errors 902 .. read from stdin here (or from w-&gt;fd) and haqndle any I/O errors
… …
899 <p>The current <code>repeat</code> value. Will be used each time the watcher times out 985 <p>The current <code>repeat</code> value. Will be used each time the watcher times out
900or <code>ev_timer_again</code> is called and determines the next timeout (if any), 986or <code>ev_timer_again</code> is called and determines the next timeout (if any),
901which is also when any modifications are taken into account.</p> 987which is also when any modifications are taken into account.</p>
902 </dd> 988 </dd>
903</dl> 989</dl>
904<p>Example: create a timer that fires after 60 seconds.</p> 990<p>Example: Create a timer that fires after 60 seconds.</p>
905<pre> static void 991<pre> static void
906 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)
907 { 993 {
908 .. one minute over, w is actually stopped right here 994 .. one minute over, w is actually stopped right here
909 } 995 }
… …
911 struct ev_timer mytimer; 997 struct ev_timer mytimer;
912 ev_timer_init (&amp;mytimer, one_minute_cb, 60., 0.); 998 ev_timer_init (&amp;mytimer, one_minute_cb, 60., 0.);
913 ev_timer_start (loop, &amp;mytimer); 999 ev_timer_start (loop, &amp;mytimer);
914 1000
915</pre> 1001</pre>
916<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
917inactivity.</p> 1003inactivity.</p>
918<pre> static void 1004<pre> static void
919 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)
920 { 1006 {
921 .. ten seconds without any activity 1007 .. ten seconds without any activity
… …
1037 <p>The current reschedule callback, or <code>0</code>, if this functionality is 1123 <p>The current reschedule callback, or <code>0</code>, if this functionality is
1038switched off. Can be changed any time, but changes only take effect when 1124switched off. Can be changed any time, but changes only take effect when
1039the periodic timer fires or <code>ev_periodic_again</code> is being called.</p> 1125the periodic timer fires or <code>ev_periodic_again</code> is being called.</p>
1040 </dd> 1126 </dd>
1041</dl> 1127</dl>
1042<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
1043system clock is divisible by 3600. The callback invocation times have 1129system clock is divisible by 3600. The callback invocation times have
1044potentially a lot of jittering, but good long-term stability.</p> 1130potentially a lot of jittering, but good long-term stability.</p>
1045<pre> static void 1131<pre> static void
1046 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)
1047 { 1133 {
… …
1051 struct ev_periodic hourly_tick; 1137 struct ev_periodic hourly_tick;
1052 ev_periodic_init (&amp;hourly_tick, clock_cb, 0., 3600., 0); 1138 ev_periodic_init (&amp;hourly_tick, clock_cb, 0., 3600., 0);
1053 ev_periodic_start (loop, &amp;hourly_tick); 1139 ev_periodic_start (loop, &amp;hourly_tick);
1054 1140
1055</pre> 1141</pre>
1056<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>
1057<pre> #include &lt;math.h&gt; 1143<pre> #include &lt;math.h&gt;
1058 1144
1059 static ev_tstamp 1145 static ev_tstamp
1060 my_scheduler_cb (struct ev_periodic *w, ev_tstamp now) 1146 my_scheduler_cb (struct ev_periodic *w, ev_tstamp now)
1061 { 1147 {
… …
1063 } 1149 }
1064 1150
1065 ev_periodic_init (&amp;hourly_tick, clock_cb, 0., 0., my_scheduler_cb); 1151 ev_periodic_init (&amp;hourly_tick, clock_cb, 0., 0., my_scheduler_cb);
1066 1152
1067</pre> 1153</pre>
1068<p>Example: call a callback every hour, starting now:</p> 1154<p>Example: Call a callback every hour, starting now:</p>
1069<pre> struct ev_periodic hourly_tick; 1155<pre> struct ev_periodic hourly_tick;
1070 ev_periodic_init (&amp;hourly_tick, clock_cb, 1156 ev_periodic_init (&amp;hourly_tick, clock_cb,
1071 fmod (ev_now (loop), 3600.), 3600., 0); 1157 fmod (ev_now (loop), 3600.), 3600., 0);
1072 ev_periodic_start (loop, &amp;hourly_tick); 1158 ev_periodic_start (loop, &amp;hourly_tick);
1073 1159
… …
1134 <dd> 1220 <dd>
1135 <p>The process exit/trace status caused by <code>rpid</code> (see your systems 1221 <p>The process exit/trace status caused by <code>rpid</code> (see your systems
1136<code>waitpid</code> and <code>sys/wait.h</code> documentation for details).</p> 1222<code>waitpid</code> and <code>sys/wait.h</code> documentation for details).</p>
1137 </dd> 1223 </dd>
1138</dl> 1224</dl>
1139<p>Example: try to exit cleanly on SIGINT and SIGTERM.</p> 1225<p>Example: Try to exit cleanly on SIGINT and SIGTERM.</p>
1140<pre> static void 1226<pre> static void
1141 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)
1142 { 1228 {
1143 ev_unloop (loop, EVUNLOOP_ALL); 1229 ev_unloop (loop, EVUNLOOP_ALL);
1144 } 1230 }
… …
1162not exist&quot; is a status change like any other. The condition &quot;path does 1248not exist&quot; is a status change like any other. The condition &quot;path does
1163not exist&quot; is signified by the <code>st_nlink</code> field being zero (which is 1249not exist&quot; is signified by the <code>st_nlink</code> field being zero (which is
1164otherwise always forced to be at least one) and all the other fields of 1250otherwise always forced to be at least one) and all the other fields of
1165the stat buffer having unspecified contents.</p> 1251the stat buffer having unspecified contents.</p>
1166<p>Since there is no standard to do this, the portable implementation simply 1252<p>Since there is no standard to do this, the portable implementation simply
1167calls <code>stat (2)</code> regulalry on the path to see if it changed somehow. You 1253calls <code>stat (2)</code> regularly on the path to see if it changed somehow. You
1168can specify a recommended polling interval for this case. If you specify 1254can specify a recommended polling interval for this case. If you specify
1169a polling interval of <code>0</code> (highly recommended!) then a <i>suitable, 1255a polling interval of <code>0</code> (highly recommended!) then a <i>suitable,
1170unspecified default</i> value will be used (which you can expect to be around 1256unspecified default</i> value will be used (which you can expect to be around
1171five seconds, although this might change dynamically). Libev will also 1257five seconds, although this might change dynamically). Libev will also
1172impose a minimum interval which is currently around <code>0.1</code>, but thats 1258impose a minimum interval which is currently around <code>0.1</code>, but thats
1173usually overkill.</p> 1259usually overkill.</p>
1174<p>This watcher type is not meant for massive numbers of stat watchers, 1260<p>This watcher type is not meant for massive numbers of stat watchers,
1175as even with OS-supported change notifications, this can be 1261as even with OS-supported change notifications, this can be
1176resource-intensive.</p> 1262resource-intensive.</p>
1177<p>At the time of this writing, no specific OS backends are implemented, but 1263<p>At the time of this writing, only the Linux inotify interface is
1178if demand increases, at least a kqueue and inotify backend will be added.</p> 1264implemented (implementing kqueue support is left as an exercise for the
1265reader). Inotify will be used to give hints only and should not change the
1266semantics of <code>ev_stat</code> watchers, which means that libev sometimes needs
1267to fall back to regular polling again even with inotify, but changes are
1268usually detected immediately, and if the file exists there will be no
1269polling.</p>
1179<dl> 1270<dl>
1180 <dt>ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)</dt> 1271 <dt>ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)</dt>
1181 <dt>ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)</dt> 1272 <dt>ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)</dt>
1182 <dd> 1273 <dd>
1183 <p>Configures the watcher to wait for status changes of the given 1274 <p>Configures the watcher to wait for status changes of the given
… …
1267 <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
1268kind. There is a <code>ev_idle_set</code> macro, but using it is utterly pointless, 1359kind. There is a <code>ev_idle_set</code> macro, but using it is utterly pointless,
1269believe me.</p> 1360believe me.</p>
1270 </dd> 1361 </dd>
1271</dl> 1362</dl>
1272<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
1273callback, free it. Alos, use no error checking, as usual.</p> 1364callback, free it. Also, use no error checking, as usual.</p>
1274<pre> static void 1365<pre> static void
1275 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)
1276 { 1367 {
1277 free (w); 1368 free (w);
1278 // now do something you wanted to do when the program has 1369 // now do something you wanted to do when the program has
… …
1480 1571
1481 1572
1482 1573
1483 1574
1484</div> 1575</div>
1485<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
1579whoever 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
1581event loop blocks next and before <code>ev_check</code> watchers are being called,
1582and 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
1584handlers 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
1589kind. There is a <code>ev_fork_set</code> macro, but using it is utterly pointless,
1590believe me.</p>
1591 </dd>
1592</dl>
1593
1594
1595
1596
1597
1598</div>
1599<h1 id="OTHER_FUNCTIONS">OTHER FUNCTIONS</h1>
1486<div id="OTHER_FUNCTIONS_CONTENT"> 1600<div id="OTHER_FUNCTIONS_CONTENT">
1487<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>
1488<dl> 1602<dl>
1489 <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>
1490 <dd> 1604 <dd>
… …
1537 1651
1538 1652
1539 1653
1540 1654
1541</div> 1655</div>
1542<h1 id="LIBEVENT_EMULATION">LIBEVENT EMULATION</h1><p><a href="#TOP" class="toplink">Top</a></p> 1656<h1 id="LIBEVENT_EMULATION">LIBEVENT EMULATION</h1>
1543<div id="LIBEVENT_EMULATION_CONTENT"> 1657<div id="LIBEVENT_EMULATION_CONTENT">
1544<p>Libev offers a compatibility emulation layer for libevent. It cannot 1658<p>Libev offers a compatibility emulation layer for libevent. It cannot
1545emulate the internals of libevent, so here are some usage hints:</p> 1659emulate the internals of libevent, so here are some usage hints:</p>
1546<dl> 1660<dl>
1547 <dt>* Use it by including &lt;event.h&gt;, as usual.</dt> 1661 <dt>* Use it by including &lt;event.h&gt;, as usual.</dt>
… …
1557 <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
1558to use the libev header file and library.</dt> 1672to use the libev header file and library.</dt>
1559</dl> 1673</dl>
1560 1674
1561</div> 1675</div>
1562<h1 id="C_SUPPORT">C++ SUPPORT</h1><p><a href="#TOP" class="toplink">Top</a></p> 1676<h1 id="C_SUPPORT">C++ SUPPORT</h1>
1563<div id="C_SUPPORT_CONTENT"> 1677<div id="C_SUPPORT_CONTENT">
1564<p>Libev comes with some simplistic wrapper classes for C++ that mainly allow 1678<p>Libev comes with some simplistic wrapper classes for C++ that mainly allow
1565you to use some convinience methods to start/stop watchers and also change 1679you to use some convinience methods to start/stop watchers and also change
1566the callback model to a model using method callbacks on objects.</p> 1680the callback model to a model using method callbacks on objects.</p>
1567<p>To use it,</p> 1681<p>To use it,</p>
… …
1656 idle (this, &amp;myclass::idle_cb) 1770 idle (this, &amp;myclass::idle_cb)
1657 { 1771 {
1658 io.start (fd, ev::READ); 1772 io.start (fd, ev::READ);
1659 } 1773 }
1660 1774
1661</pre>
1662 1775
1776
1777
1778</pre>
1779
1663</div> 1780</div>
1664<h1 id="EMBEDDING">EMBEDDING</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
1785callbacks 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
1787following 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 (&quot;ev
1792loop argument&quot;). 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,
1800which 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 (&quot;ev
1805loop parameter&quot;). 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
1815suitable 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
1820loop, if multiple loops are supported (&quot;ev loop default&quot;).</p>
1821 </dd>
1822</dl>
1823<p>Example: Declare and initialise a check watcher, working regardless of
1824wether 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 (&amp;check, check_cb);
1833 ev_check_start (EV_DEFAULT_ &amp;check);
1834 ev_loop (EV_DEFAULT_ 0);
1835
1836
1837
1838
1839</pre>
1840
1841</div>
1842<h1 id="EMBEDDING">EMBEDDING</h1>
1665<div id="EMBEDDING_CONTENT"> 1843<div id="EMBEDDING_CONTENT">
1666<p>Libev can (and often is) directly embedded into host 1844<p>Libev can (and often is) directly embedded into host
1667applications. Examples of applications that embed it include the Deliantra 1845applications. Examples of applications that embed it include the Deliantra
1668Game Server, the EV perl module, the GNU Virtual Private Ethernet (gvpe) 1846Game Server, the EV perl module, the GNU Virtual Private Ethernet (gvpe)
1669and rxvt-unicode.</p> 1847and rxvt-unicode.</p>
… …
1843 </dd> 2021 </dd>
1844 <dt>EV_USE_DEVPOLL</dt> 2022 <dt>EV_USE_DEVPOLL</dt>
1845 <dd> 2023 <dd>
1846 <p>reserved for future expansion, works like the USE symbols above.</p> 2024 <p>reserved for future expansion, works like the USE symbols above.</p>
1847 </dd> 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
2029interface to speed up <code>ev_stat</code> watchers. Its actual availability will
2030be detected at runtime.</p>
2031 </dd>
1848 <dt>EV_H</dt> 2032 <dt>EV_H</dt>
1849 <dd> 2033 <dd>
1850 <p>The name of the <cite>ev.h</cite> header file used to include it. The default if 2034 <p>The name of the <cite>ev.h</cite> header file used to include it. The default if
1851undefined is <code>&lt;ev.h&gt;</code> in <cite>event.h</cite> and <code>&quot;ev.h&quot;</code> in <cite>ev.c</cite>. This 2035undefined is <code>&lt;ev.h&gt;</code> in <cite>event.h</cite> and <code>&quot;ev.h&quot;</code> in <cite>ev.c</cite>. This
1852can be used to virtually rename the <cite>ev.h</cite> header file in case of conflicts.</p> 2036can be used to virtually rename the <cite>ev.h</cite> header file in case of conflicts.</p>
… …
1891 <dt>EV_STAT_ENABLE</dt> 2075 <dt>EV_STAT_ENABLE</dt>
1892 <dd> 2076 <dd>
1893 <p>If undefined or defined to be <code>1</code>, then stat watchers are supported. If 2077 <p>If undefined or defined to be <code>1</code>, then stat watchers are supported. If
1894defined to be <code>0</code>, then they are not.</p> 2078defined to be <code>0</code>, then they are not.</p>
1895 </dd> 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
2083defined to be <code>0</code>, then they are not.</p>
2084 </dd>
1896 <dt>EV_MINIMAL</dt> 2085 <dt>EV_MINIMAL</dt>
1897 <dd> 2086 <dd>
1898 <p>If you need to shave off some kilobytes of code at the expense of some 2087 <p>If you need to shave off some kilobytes of code at the expense of some
1899speed, define this symbol to <code>1</code>. Currently only used for gcc to override 2088speed, define this symbol to <code>1</code>. Currently only used for gcc to override
1900some inlining decisions, saves roughly 30% codesize of amd64.</p> 2089some 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
2094pid. The default size is <code>16</code> (or <code>1</code> with <code>EV_MINIMAL</code>), usually more
2095than enough. If you need to manage thousands of children you might want to
2096increase 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
2101inotify watch id. The default size is <code>16</code> (or <code>1</code> with <code>EV_MINIMAL</code>),
2102usually more than enough. If you need to manage thousands of <code>ev_stat</code>
2103watchers you might want to increase this value (<i>must</i> be a power of
2104two).</p>
1901 </dd> 2105 </dd>
1902 <dt>EV_COMMON</dt> 2106 <dt>EV_COMMON</dt>
1903 <dd> 2107 <dd>
1904 <p>By default, all watchers have a <code>void *data</code> member. By redefining 2108 <p>By default, all watchers have a <code>void *data</code> member. By redefining
1905this macro to a something else you can include more and other types of 2109this macro to a something else you can include more and other types of
… …
1951 2155
1952 2156
1953</pre> 2157</pre>
1954 2158
1955</div> 2159</div>
1956<h1 id="COMPLEXITIES">COMPLEXITIES</h1><p><a href="#TOP" class="toplink">Top</a></p> 2160<h1 id="COMPLEXITIES">COMPLEXITIES</h1>
1957<div id="COMPLEXITIES_CONTENT"> 2161<div id="COMPLEXITIES_CONTENT">
1958 <p>In this section the complexities of (many of) the algorithms used inside 2162 <p>In this section the complexities of (many of) the algorithms used inside
1959libev will be explained. For complexity discussions about backends see the 2163libev will be explained. For complexity discussions about backends see the
1960documentation for <code>ev_default_init</code>.</p> 2164documentation for <code>ev_default_init</code>.</p>
1961 <p> 2165 <p>
1962 <dl> 2166 <dl>
1963 <dt>Starting and stopping timer/periodic watchers: O(log skipped_other_timers)</dt> 2167 <dt>Starting and stopping timer/periodic watchers: O(log skipped_other_timers)</dt>
1964 <dt>Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)</dt> 2168 <dt>Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)</dt>
1965 <dt>Starting io/check/prepare/idle/signal/child watchers: O(1)</dt> 2169 <dt>Starting io/check/prepare/idle/signal/child watchers: O(1)</dt>
1966 <dt>Stopping check/prepare/idle watchers: O(1)</dt> 2170 <dt>Stopping check/prepare/idle watchers: O(1)</dt>
1967 <dt>Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % 16))</dt> 2171 <dt>Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))</dt>
1968 <dt>Finding the next timer per loop iteration: O(1)</dt> 2172 <dt>Finding the next timer per loop iteration: O(1)</dt>
1969 <dt>Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)</dt> 2173 <dt>Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)</dt>
1970 <dt>Activating one watcher: O(1)</dt> 2174 <dt>Activating one watcher: O(1)</dt>
1971 </dl> 2175 </dl>
1972 </p> 2176 </p>
… …
1974 2178
1975 2179
1976 2180
1977 2181
1978</div> 2182</div>
1979<h1 id="AUTHOR">AUTHOR</h1><p><a href="#TOP" class="toplink">Top</a></p> 2183<h1 id="AUTHOR">AUTHOR</h1>
1980<div id="AUTHOR_CONTENT"> 2184<div id="AUTHOR_CONTENT">
1981 <p>Marc Lehmann &lt;libev@schmorp.de&gt;.</p> 2185 <p>Marc Lehmann &lt;libev@schmorp.de&gt;.</p>
1982 2186
1983</div> 2187</div>
1984</div></body> 2188</div></body>

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