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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 20:38:24 2007" /> 9 <meta name="created" content="Thu Nov 29 21:05:58 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> #include &lt;ev.h&gt; 72<pre> #include &lt;ev.h&gt;
72 73
73</pre> 74</pre>
74 75
75</div> 76</div>
76<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>
77<div id="DESCRIPTION_CONTENT"> 123<div id="DESCRIPTION_CONTENT">
78<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
79file descriptor being readable or a timeout occuring), and it will manage 125file descriptor being readable or a timeout occuring), and it will manage
80these event sources and provide your program with events.</p> 126these event sources and provide your program with events.</p>
81<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
… …
85watchers</i>, which are relatively small C structures you initialise with the 131watchers</i>, which are relatively small C structures you initialise with the
86details 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
87watcher.</p> 133watcher.</p>
88 134
89</div> 135</div>
90<h1 id="FEATURES">FEATURES</h1><p><a href="#TOP" class="toplink">Top</a></p> 136<h1 id="FEATURES">FEATURES</h1>
91<div id="FEATURES_CONTENT"> 137<div id="FEATURES_CONTENT">
92<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
93kqueue mechanisms for file descriptor events, relative timers, absolute 139BSD-specific <code>kqueue</code> and the Solaris-specific event port mechanisms
94timers with customised rescheduling, signal events, process status change 140for file descriptor events (<code>ev_io</code>), the Linux <code>inotify</code> interface
95events (related to SIGCHLD), and event watchers dealing with the event 141(for <code>ev_stat</code>), relative timers (<code>ev_timer</code>), absolute timers
96loop 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
97fast (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
98it to libevent for example).</p> 150for example).</p>
99 151
100</div> 152</div>
101<h1 id="CONVENTIONS">CONVENTIONS</h1><p><a href="#TOP" class="toplink">Top</a></p> 153<h1 id="CONVENTIONS">CONVENTIONS</h1>
102<div id="CONVENTIONS_CONTENT"> 154<div id="CONVENTIONS_CONTENT">
103<p>Libev is very configurable. In this manual the default configuration 155<p>Libev is very configurable. In this manual the default configuration will
104will be described, which supports multiple event loops. For more info 156be described, which supports multiple event loops. For more info about
105about various configuration options please have a look at the file 157various configuration options please have a look at <strong>EMBED</strong> section in
106<cite>README.embed</cite> in the libev distribution. If libev was configured without 158this manual. If libev was configured without support for multiple event
107support for multiple event loops, then all functions taking an initial 159loops, then all functions taking an initial argument of name <code>loop</code>
108argument 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>
109will not have this argument.</p>
110 161
111</div> 162</div>
112<h1 id="TIME_REPRESENTATION">TIME REPRESENTATION</h1><p><a href="#TOP" class="toplink">Top</a></p> 163<h1 id="TIME_REPRESENTATION">TIME REPRESENTATION</h1>
113<div id="TIME_REPRESENTATION_CONTENT"> 164<div id="TIME_REPRESENTATION_CONTENT">
114<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
115(fractional) number of seconds since the (POSIX) epoch (somewhere near 166(fractional) number of seconds since the (POSIX) epoch (somewhere near
116the 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
117called <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
118to 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
119it, you should treat it as such.</p> 170it, you should treat it as such.</p>
120 171
121</div> 172</div>
122<h1 id="GLOBAL_FUNCTIONS">GLOBAL FUNCTIONS</h1><p><a href="#TOP" class="toplink">Top</a></p> 173<h1 id="GLOBAL_FUNCTIONS">GLOBAL FUNCTIONS</h1>
123<div id="GLOBAL_FUNCTIONS_CONTENT"> 174<div id="GLOBAL_FUNCTIONS_CONTENT">
124<p>These functions can be called anytime, even before initialising the 175<p>These functions can be called anytime, even before initialising the
125library in any way.</p> 176library in any way.</p>
126<dl> 177<dl>
127 <dt>ev_tstamp ev_time ()</dt> 178 <dt>ev_tstamp ev_time ()</dt>
… …
140version of the library your program was compiled against.</p> 191version of the library your program was compiled against.</p>
141 <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,
142as this indicates an incompatible change. Minor versions are usually 193as this indicates an incompatible change. Minor versions are usually
143compatible to older versions, so a larger minor version alone is usually 194compatible to older versions, so a larger minor version alone is usually
144not a problem.</p> 195not a problem.</p>
145 <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
146version:</p> 197version.</p>
147<pre> assert ((&quot;libev version mismatch&quot;, 198<pre> assert ((&quot;libev version mismatch&quot;,
148 ev_version_major () == EV_VERSION_MAJOR 199 ev_version_major () == EV_VERSION_MAJOR
149 &amp;&amp; ev_version_minor () &gt;= EV_VERSION_MINOR)); 200 &amp;&amp; ev_version_minor () &gt;= EV_VERSION_MINOR));
150 201
151</pre> 202</pre>
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179might 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
180<code>ev_embeddable_backends () &amp; ev_supported_backends ()</code>, likewise for 231<code>ev_embeddable_backends () &amp; ev_supported_backends ()</code>, likewise for
181recommended ones.</p> 232recommended ones.</p>
182 <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>
183 </dd> 234 </dd>
184 <dt>ev_set_allocator (void *(*cb)(void *ptr, size_t size))</dt> 235 <dt>ev_set_allocator (void *(*cb)(void *ptr, long size))</dt>
185 <dd> 236 <dd>
186 <p>Sets the allocation function to use (the prototype and semantics are 237 <p>Sets the allocation function to use (the prototype is similar - the
187identical to the realloc C function). It is used to allocate and free 238semantics is identical - to the realloc C function). It is used to
188memory (no surprises here). If it returns zero when memory needs to be 239allocate and free memory (no surprises here). If it returns zero when
189allocated, the library might abort or take some potentially destructive 240memory needs to be allocated, the library might abort or take some
190action. The default is your system realloc function.</p> 241potentially destructive action. The default is your system realloc
242function.</p>
191 <p>You could override this function in high-availability programs to, say, 243 <p>You could override this function in high-availability programs to, say,
192free some memory if it cannot allocate memory, to use a special allocator, 244free some memory if it cannot allocate memory, to use a special allocator,
193or even to sleep a while and retry until some memory is available.</p> 245or even to sleep a while and retry until some memory is available.</p>
194 <p>Example: replace the libev allocator with one that waits a bit and then 246 <p>Example: Replace the libev allocator with one that waits a bit and then
195retries: better than mine).</p> 247retries).</p>
196<pre> static void * 248<pre> static void *
197 persistent_realloc (void *ptr, size_t size) 249 persistent_realloc (void *ptr, size_t size)
198 { 250 {
199 for (;;) 251 for (;;)
200 { 252 {
… …
219indicating the system call or subsystem causing the problem. If this 271indicating the system call or subsystem causing the problem. If this
220callback is set, then libev will expect it to remedy the sitution, no 272callback is set, then libev will expect it to remedy the sitution, no
221matter what, when it returns. That is, libev will generally retry the 273matter what, when it returns. That is, libev will generally retry the
222requested operation, or, if the condition doesn't go away, do bad stuff 274requested operation, or, if the condition doesn't go away, do bad stuff
223(such as abort).</p> 275(such as abort).</p>
224 <p>Example: do the same thing as libev does internally:</p> 276 <p>Example: This is basically the same thing that libev does internally, too.</p>
225<pre> static void 277<pre> static void
226 fatal_error (const char *msg) 278 fatal_error (const char *msg)
227 { 279 {
228 perror (msg); 280 perror (msg);
229 abort (); 281 abort ();
… …
235</pre> 287</pre>
236 </dd> 288 </dd>
237</dl> 289</dl>
238 290
239</div> 291</div>
240<h1 id="FUNCTIONS_CONTROLLING_THE_EVENT_LOOP">FUNCTIONS CONTROLLING THE EVENT LOOP</h1><p><a href="#TOP" class="toplink">Top</a></p> 292<h1 id="FUNCTIONS_CONTROLLING_THE_EVENT_LOOP">FUNCTIONS CONTROLLING THE EVENT LOOP</h1>
241<div id="FUNCTIONS_CONTROLLING_THE_EVENT_LOOP-2"> 293<div id="FUNCTIONS_CONTROLLING_THE_EVENT_LOOP-2">
242<p>An event loop is described by a <code>struct ev_loop *</code>. The library knows two 294<p>An event loop is described by a <code>struct ev_loop *</code>. The library knows two
243types of such loops, the <i>default</i> loop, which supports signals and child 295types of such loops, the <i>default</i> loop, which supports signals and child
244events, and dynamically created loops which do not.</p> 296events, and dynamically created loops which do not.</p>
245<p>If you use threads, a common model is to run the default event loop 297<p>If you use threads, a common model is to run the default event loop
… …
273or setgid) then libev will <i>not</i> look at the environment variable 325or setgid) then libev will <i>not</i> look at the environment variable
274<code>LIBEV_FLAGS</code>. Otherwise (the default), this environment variable will 326<code>LIBEV_FLAGS</code>. Otherwise (the default), this environment variable will
275override the flags completely if it is found in the environment. This is 327override the flags completely if it is found in the environment. This is
276useful to try out specific backends to test their performance, or to work 328useful to try out specific backends to test their performance, or to work
277around bugs.</p> 329around bugs.</p>
330 </dd>
331 <dt><code>EVFLAG_FORKCHECK</code></dt>
332 <dd>
333 <p>Instead of calling <code>ev_default_fork</code> or <code>ev_loop_fork</code> manually after
334a fork, you can also make libev check for a fork in each iteration by
335enabling this flag.</p>
336 <p>This works by calling <code>getpid ()</code> on every iteration of the loop,
337and thus this might slow down your event loop if you do a lot of loop
338iterations and little real work, but is usually not noticable (on my
339Linux system for example, <code>getpid</code> is actually a simple 5-insn sequence
340without a syscall and thus <i>very</i> fast, but my Linux system also has
341<code>pthread_atfork</code> which is even faster).</p>
342 <p>The big advantage of this flag is that you can forget about fork (and
343forget about forgetting to tell libev about forking) when you use this
344flag.</p>
345 <p>This flag setting cannot be overriden or specified in the <code>LIBEV_FLAGS</code>
346environment variable.</p>
278 </dd> 347 </dd>
279 <dt><code>EVBACKEND_SELECT</code> (value 1, portable select backend)</dt> 348 <dt><code>EVBACKEND_SELECT</code> (value 1, portable select backend)</dt>
280 <dd> 349 <dd>
281 <p>This is your standard select(2) backend. Not <i>completely</i> standard, as 350 <p>This is your standard select(2) backend. Not <i>completely</i> standard, as
282libev tries to roll its own fd_set with no limits on the number of fds, 351libev tries to roll its own fd_set with no limits on the number of fds,
… …
365 <dd> 434 <dd>
366 <p>Similar to <code>ev_default_loop</code>, but always creates a new event loop that is 435 <p>Similar to <code>ev_default_loop</code>, but always creates a new event loop that is
367always distinct from the default loop. Unlike the default loop, it cannot 436always distinct from the default loop. Unlike the default loop, it cannot
368handle signal and child watchers, and attempts to do so will be greeted by 437handle signal and child watchers, and attempts to do so will be greeted by
369undefined behaviour (or a failed assertion if assertions are enabled).</p> 438undefined behaviour (or a failed assertion if assertions are enabled).</p>
370 <p>Example: try to create a event loop that uses epoll and nothing else.</p> 439 <p>Example: Try to create a event loop that uses epoll and nothing else.</p>
371<pre> struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV); 440<pre> struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV);
372 if (!epoller) 441 if (!epoller)
373 fatal (&quot;no epoll found here, maybe it hides under your chair&quot;); 442 fatal (&quot;no epoll found here, maybe it hides under your chair&quot;);
374 443
375</pre> 444</pre>
… …
468 be handled here by queueing them when their watcher gets executed. 537 be handled here by queueing them when their watcher gets executed.
469 - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK 538 - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK
470 were used, return, otherwise continue with step *. 539 were used, return, otherwise continue with step *.
471 540
472</pre> 541</pre>
473 <p>Example: queue some jobs and then loop until no events are outsanding 542 <p>Example: Queue some jobs and then loop until no events are outsanding
474anymore.</p> 543anymore.</p>
475<pre> ... queue jobs here, make sure they register event watchers as long 544<pre> ... queue jobs here, make sure they register event watchers as long
476 ... as they still have work to do (even an idle watcher will do..) 545 ... as they still have work to do (even an idle watcher will do..)
477 ev_loop (my_loop, 0); 546 ev_loop (my_loop, 0);
478 ... jobs done. yeah! 547 ... jobs done. yeah!
… …
497example, libev itself uses this for its internal signal pipe: It is not 566example, libev itself uses this for its internal signal pipe: It is not
498visible to the libev user and should not keep <code>ev_loop</code> from exiting if 567visible to the libev user and should not keep <code>ev_loop</code> from exiting if
499no event watchers registered by it are active. It is also an excellent 568no event watchers registered by it are active. It is also an excellent
500way to do this for generic recurring timers or from within third-party 569way to do this for generic recurring timers or from within third-party
501libraries. Just remember to <i>unref after start</i> and <i>ref before stop</i>.</p> 570libraries. Just remember to <i>unref after start</i> and <i>ref before stop</i>.</p>
502 <p>Example: create a signal watcher, but keep it from keeping <code>ev_loop</code> 571 <p>Example: Create a signal watcher, but keep it from keeping <code>ev_loop</code>
503running when nothing else is active.</p> 572running when nothing else is active.</p>
504<pre> struct dv_signal exitsig; 573<pre> struct ev_signal exitsig;
505 ev_signal_init (&amp;exitsig, sig_cb, SIGINT); 574 ev_signal_init (&amp;exitsig, sig_cb, SIGINT);
506 ev_signal_start (myloop, &amp;exitsig); 575 ev_signal_start (loop, &amp;exitsig);
507 evf_unref (myloop); 576 evf_unref (loop);
508 577
509</pre> 578</pre>
510 <p>Example: for some weird reason, unregister the above signal handler again.</p> 579 <p>Example: For some weird reason, unregister the above signal handler again.</p>
511<pre> ev_ref (myloop); 580<pre> ev_ref (loop);
512 ev_signal_stop (myloop, &amp;exitsig); 581 ev_signal_stop (loop, &amp;exitsig);
513 582
514</pre> 583</pre>
515 </dd> 584 </dd>
516</dl> 585</dl>
517 586
518 587
519 588
520 589
521 590
522</div> 591</div>
523<h1 id="ANATOMY_OF_A_WATCHER">ANATOMY OF A WATCHER</h1><p><a href="#TOP" class="toplink">Top</a></p> 592<h1 id="ANATOMY_OF_A_WATCHER">ANATOMY OF A WATCHER</h1>
524<div id="ANATOMY_OF_A_WATCHER_CONTENT"> 593<div id="ANATOMY_OF_A_WATCHER_CONTENT">
525<p>A watcher is a structure that you create and register to record your 594<p>A watcher is a structure that you create and register to record your
526interest in some event. For instance, if you want to wait for STDIN to 595interest in some event. For instance, if you want to wait for STDIN to
527become readable, you would create an <code>ev_io</code> watcher for that:</p> 596become readable, you would create an <code>ev_io</code> watcher for that:</p>
528<pre> static void my_cb (struct ev_loop *loop, struct ev_io *w, int revents) 597<pre> static void my_cb (struct ev_loop *loop, struct ev_io *w, int revents)
… …
691events but its callback has not yet been invoked). As long as a watcher 760events but its callback has not yet been invoked). As long as a watcher
692is pending (but not active) you must not call an init function on it (but 761is pending (but not active) you must not call an init function on it (but
693<code>ev_TYPE_set</code> is safe) and you must make sure the watcher is available to 762<code>ev_TYPE_set</code> is safe) and you must make sure the watcher is available to
694libev (e.g. you cnanot <code>free ()</code> it).</p> 763libev (e.g. you cnanot <code>free ()</code> it).</p>
695 </dd> 764 </dd>
696 <dt>callback = ev_cb (ev_TYPE *watcher)</dt> 765 <dt>callback ev_cb (ev_TYPE *watcher)</dt>
697 <dd> 766 <dd>
698 <p>Returns the callback currently set on the watcher.</p> 767 <p>Returns the callback currently set on the watcher.</p>
699 </dd> 768 </dd>
700 <dt>ev_cb_set (ev_TYPE *watcher, callback)</dt> 769 <dt>ev_cb_set (ev_TYPE *watcher, callback)</dt>
701 <dd> 770 <dd>
… …
733 struct my_io *w = (struct my_io *)w_; 802 struct my_io *w = (struct my_io *)w_;
734 ... 803 ...
735 } 804 }
736 805
737</pre> 806</pre>
738<p>More interesting and less C-conformant ways of catsing your callback type 807<p>More interesting and less C-conformant ways of casting your callback type
739have been omitted....</p> 808instead have been omitted.</p>
809<p>Another common scenario is having some data structure with multiple
810watchers:</p>
811<pre> struct my_biggy
812 {
813 int some_data;
814 ev_timer t1;
815 ev_timer t2;
816 }
740 817
818</pre>
819<p>In this case getting the pointer to <code>my_biggy</code> is a bit more complicated,
820you need to use <code>offsetof</code>:</p>
821<pre> #include &lt;stddef.h&gt;
741 822
823 static void
824 t1_cb (EV_P_ struct ev_timer *w, int revents)
825 {
826 struct my_biggy big = (struct my_biggy *
827 (((char *)w) - offsetof (struct my_biggy, t1));
828 }
742 829
830 static void
831 t2_cb (EV_P_ struct ev_timer *w, int revents)
832 {
833 struct my_biggy big = (struct my_biggy *
834 (((char *)w) - offsetof (struct my_biggy, t2));
835 }
743 836
744 837
838
839
840</pre>
841
745</div> 842</div>
746<h1 id="WATCHER_TYPES">WATCHER TYPES</h1><p><a href="#TOP" class="toplink">Top</a></p> 843<h1 id="WATCHER_TYPES">WATCHER TYPES</h1>
747<div id="WATCHER_TYPES_CONTENT"> 844<div id="WATCHER_TYPES_CONTENT">
748<p>This section describes each watcher in detail, but will not repeat 845<p>This section describes each watcher in detail, but will not repeat
749information given in the last section. Any initialisation/set macros, 846information given in the last section. Any initialisation/set macros,
750functions and members specific to the watcher type are explained.</p> 847functions and members specific to the watcher type are explained.</p>
751<p>Members are additionally marked with either <i>[read-only]</i>, meaning that, 848<p>Members are additionally marked with either <i>[read-only]</i>, meaning that,
… …
811 <dt>int events [read-only]</dt> 908 <dt>int events [read-only]</dt>
812 <dd> 909 <dd>
813 <p>The events being watched.</p> 910 <p>The events being watched.</p>
814 </dd> 911 </dd>
815</dl> 912</dl>
816<p>Example: call <code>stdin_readable_cb</code> when STDIN_FILENO has become, well 913<p>Example: Call <code>stdin_readable_cb</code> when STDIN_FILENO has become, well
817readable, but only once. Since it is likely line-buffered, you could 914readable, but only once. Since it is likely line-buffered, you could
818attempt to read a whole line in the callback:</p> 915attempt to read a whole line in the callback.</p>
819<pre> static void 916<pre> static void
820 stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents) 917 stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents)
821 { 918 {
822 ev_io_stop (loop, w); 919 ev_io_stop (loop, w);
823 .. read from stdin here (or from w-&gt;fd) and haqndle any I/O errors 920 .. read from stdin here (or from w-&gt;fd) and haqndle any I/O errors
… …
872 </dd> 969 </dd>
873 <dt>ev_timer_again (loop)</dt> 970 <dt>ev_timer_again (loop)</dt>
874 <dd> 971 <dd>
875 <p>This will act as if the timer timed out and restart it again if it is 972 <p>This will act as if the timer timed out and restart it again if it is
876repeating. The exact semantics are:</p> 973repeating. The exact semantics are:</p>
974 <p>If the timer is pending, its pending status is cleared.</p>
877 <p>If the timer is started but nonrepeating, stop it.</p> 975 <p>If the timer is started but nonrepeating, stop it (as if it timed out).</p>
878 <p>If the timer is repeating, either start it if necessary (with the repeat 976 <p>If the timer is repeating, either start it if necessary (with the
879value), or reset the running timer to the repeat value.</p> 977<code>repeat</code> value), or reset the running timer to the <code>repeat</code> value.</p>
880 <p>This sounds a bit complicated, but here is a useful and typical 978 <p>This sounds a bit complicated, but here is a useful and typical
881example: Imagine you have a tcp connection and you want a so-called 979example: Imagine you have a tcp connection and you want a so-called idle
882idle timeout, that is, you want to be called when there have been, 980timeout, that is, you want to be called when there have been, say, 60
883say, 60 seconds of inactivity on the socket. The easiest way to do 981seconds of inactivity on the socket. The easiest way to do this is to
884this is to configure an <code>ev_timer</code> with <code>after</code>=<code>repeat</code>=<code>60</code> and calling 982configure an <code>ev_timer</code> with a <code>repeat</code> value of <code>60</code> and then call
885<code>ev_timer_again</code> each time you successfully read or write some data. If 983<code>ev_timer_again</code> each time you successfully read or write some data. If
886you go into an idle state where you do not expect data to travel on the 984you go into an idle state where you do not expect data to travel on the
887socket, you can stop the timer, and again will automatically restart it if 985socket, you can <code>ev_timer_stop</code> the timer, and <code>ev_timer_again</code> will
888need be.</p> 986automatically restart it if need be.</p>
889 <p>You can also ignore the <code>after</code> value and <code>ev_timer_start</code> altogether 987 <p>That means you can ignore the <code>after</code> value and <code>ev_timer_start</code>
890and only ever use the <code>repeat</code> value:</p> 988altogether and only ever use the <code>repeat</code> value and <code>ev_timer_again</code>:</p>
891<pre> ev_timer_init (timer, callback, 0., 5.); 989<pre> ev_timer_init (timer, callback, 0., 5.);
892 ev_timer_again (loop, timer); 990 ev_timer_again (loop, timer);
893 ... 991 ...
894 timer-&gt;again = 17.; 992 timer-&gt;again = 17.;
895 ev_timer_again (loop, timer); 993 ev_timer_again (loop, timer);
896 ... 994 ...
897 timer-&gt;again = 10.; 995 timer-&gt;again = 10.;
898 ev_timer_again (loop, timer); 996 ev_timer_again (loop, timer);
899 997
900</pre> 998</pre>
901 <p>This is more efficient then stopping/starting the timer eahc time you want 999 <p>This is more slightly efficient then stopping/starting the timer each time
902to modify its timeout value.</p> 1000you want to modify its timeout value.</p>
903 </dd> 1001 </dd>
904 <dt>ev_tstamp repeat [read-write]</dt> 1002 <dt>ev_tstamp repeat [read-write]</dt>
905 <dd> 1003 <dd>
906 <p>The current <code>repeat</code> value. Will be used each time the watcher times out 1004 <p>The current <code>repeat</code> value. Will be used each time the watcher times out
907or <code>ev_timer_again</code> is called and determines the next timeout (if any), 1005or <code>ev_timer_again</code> is called and determines the next timeout (if any),
908which is also when any modifications are taken into account.</p> 1006which is also when any modifications are taken into account.</p>
909 </dd> 1007 </dd>
910</dl> 1008</dl>
911<p>Example: create a timer that fires after 60 seconds.</p> 1009<p>Example: Create a timer that fires after 60 seconds.</p>
912<pre> static void 1010<pre> static void
913 one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents) 1011 one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents)
914 { 1012 {
915 .. one minute over, w is actually stopped right here 1013 .. one minute over, w is actually stopped right here
916 } 1014 }
… …
918 struct ev_timer mytimer; 1016 struct ev_timer mytimer;
919 ev_timer_init (&amp;mytimer, one_minute_cb, 60., 0.); 1017 ev_timer_init (&amp;mytimer, one_minute_cb, 60., 0.);
920 ev_timer_start (loop, &amp;mytimer); 1018 ev_timer_start (loop, &amp;mytimer);
921 1019
922</pre> 1020</pre>
923<p>Example: create a timeout timer that times out after 10 seconds of 1021<p>Example: Create a timeout timer that times out after 10 seconds of
924inactivity.</p> 1022inactivity.</p>
925<pre> static void 1023<pre> static void
926 timeout_cb (struct ev_loop *loop, struct ev_timer *w, int revents) 1024 timeout_cb (struct ev_loop *loop, struct ev_timer *w, int revents)
927 { 1025 {
928 .. ten seconds without any activity 1026 .. ten seconds without any activity
… …
1044 <p>The current reschedule callback, or <code>0</code>, if this functionality is 1142 <p>The current reschedule callback, or <code>0</code>, if this functionality is
1045switched off. Can be changed any time, but changes only take effect when 1143switched off. Can be changed any time, but changes only take effect when
1046the periodic timer fires or <code>ev_periodic_again</code> is being called.</p> 1144the periodic timer fires or <code>ev_periodic_again</code> is being called.</p>
1047 </dd> 1145 </dd>
1048</dl> 1146</dl>
1049<p>Example: call a callback every hour, or, more precisely, whenever the 1147<p>Example: Call a callback every hour, or, more precisely, whenever the
1050system clock is divisible by 3600. The callback invocation times have 1148system clock is divisible by 3600. The callback invocation times have
1051potentially a lot of jittering, but good long-term stability.</p> 1149potentially a lot of jittering, but good long-term stability.</p>
1052<pre> static void 1150<pre> static void
1053 clock_cb (struct ev_loop *loop, struct ev_io *w, int revents) 1151 clock_cb (struct ev_loop *loop, struct ev_io *w, int revents)
1054 { 1152 {
… …
1058 struct ev_periodic hourly_tick; 1156 struct ev_periodic hourly_tick;
1059 ev_periodic_init (&amp;hourly_tick, clock_cb, 0., 3600., 0); 1157 ev_periodic_init (&amp;hourly_tick, clock_cb, 0., 3600., 0);
1060 ev_periodic_start (loop, &amp;hourly_tick); 1158 ev_periodic_start (loop, &amp;hourly_tick);
1061 1159
1062</pre> 1160</pre>
1063<p>Example: the same as above, but use a reschedule callback to do it:</p> 1161<p>Example: The same as above, but use a reschedule callback to do it:</p>
1064<pre> #include &lt;math.h&gt; 1162<pre> #include &lt;math.h&gt;
1065 1163
1066 static ev_tstamp 1164 static ev_tstamp
1067 my_scheduler_cb (struct ev_periodic *w, ev_tstamp now) 1165 my_scheduler_cb (struct ev_periodic *w, ev_tstamp now)
1068 { 1166 {
… …
1070 } 1168 }
1071 1169
1072 ev_periodic_init (&amp;hourly_tick, clock_cb, 0., 0., my_scheduler_cb); 1170 ev_periodic_init (&amp;hourly_tick, clock_cb, 0., 0., my_scheduler_cb);
1073 1171
1074</pre> 1172</pre>
1075<p>Example: call a callback every hour, starting now:</p> 1173<p>Example: Call a callback every hour, starting now:</p>
1076<pre> struct ev_periodic hourly_tick; 1174<pre> struct ev_periodic hourly_tick;
1077 ev_periodic_init (&amp;hourly_tick, clock_cb, 1175 ev_periodic_init (&amp;hourly_tick, clock_cb,
1078 fmod (ev_now (loop), 3600.), 3600., 0); 1176 fmod (ev_now (loop), 3600.), 3600., 0);
1079 ev_periodic_start (loop, &amp;hourly_tick); 1177 ev_periodic_start (loop, &amp;hourly_tick);
1080 1178
… …
1141 <dd> 1239 <dd>
1142 <p>The process exit/trace status caused by <code>rpid</code> (see your systems 1240 <p>The process exit/trace status caused by <code>rpid</code> (see your systems
1143<code>waitpid</code> and <code>sys/wait.h</code> documentation for details).</p> 1241<code>waitpid</code> and <code>sys/wait.h</code> documentation for details).</p>
1144 </dd> 1242 </dd>
1145</dl> 1243</dl>
1146<p>Example: try to exit cleanly on SIGINT and SIGTERM.</p> 1244<p>Example: Try to exit cleanly on SIGINT and SIGTERM.</p>
1147<pre> static void 1245<pre> static void
1148 sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) 1246 sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents)
1149 { 1247 {
1150 ev_unloop (loop, EVUNLOOP_ALL); 1248 ev_unloop (loop, EVUNLOOP_ALL);
1151 } 1249 }
… …
1168<p>The path does not need to exist: changing from &quot;path exists&quot; to &quot;path does 1266<p>The path does not need to exist: changing from &quot;path exists&quot; to &quot;path does
1169not exist&quot; is a status change like any other. The condition &quot;path does 1267not exist&quot; is a status change like any other. The condition &quot;path does
1170not exist&quot; is signified by the <code>st_nlink</code> field being zero (which is 1268not exist&quot; is signified by the <code>st_nlink</code> field being zero (which is
1171otherwise always forced to be at least one) and all the other fields of 1269otherwise always forced to be at least one) and all the other fields of
1172the stat buffer having unspecified contents.</p> 1270the stat buffer having unspecified contents.</p>
1271<p>The path <i>should</i> be absolute and <i>must not</i> end in a slash. If it is
1272relative and your working directory changes, the behaviour is undefined.</p>
1173<p>Since there is no standard to do this, the portable implementation simply 1273<p>Since there is no standard to do this, the portable implementation simply
1174calls <code>stat (2)</code> regulalry on the path to see if it changed somehow. You 1274calls <code>stat (2)</code> regularly on the path to see if it changed somehow. You
1175can specify a recommended polling interval for this case. If you specify 1275can specify a recommended polling interval for this case. If you specify
1176a polling interval of <code>0</code> (highly recommended!) then a <i>suitable, 1276a polling interval of <code>0</code> (highly recommended!) then a <i>suitable,
1177unspecified default</i> value will be used (which you can expect to be around 1277unspecified default</i> value will be used (which you can expect to be around
1178five seconds, although this might change dynamically). Libev will also 1278five seconds, although this might change dynamically). Libev will also
1179impose a minimum interval which is currently around <code>0.1</code>, but thats 1279impose a minimum interval which is currently around <code>0.1</code>, but thats
1180usually overkill.</p> 1280usually overkill.</p>
1181<p>This watcher type is not meant for massive numbers of stat watchers, 1281<p>This watcher type is not meant for massive numbers of stat watchers,
1182as even with OS-supported change notifications, this can be 1282as even with OS-supported change notifications, this can be
1183resource-intensive.</p> 1283resource-intensive.</p>
1184<p>At the time of this writing, no specific OS backends are implemented, but 1284<p>At the time of this writing, only the Linux inotify interface is
1185if demand increases, at least a kqueue and inotify backend will be added.</p> 1285implemented (implementing kqueue support is left as an exercise for the
1286reader). Inotify will be used to give hints only and should not change the
1287semantics of <code>ev_stat</code> watchers, which means that libev sometimes needs
1288to fall back to regular polling again even with inotify, but changes are
1289usually detected immediately, and if the file exists there will be no
1290polling.</p>
1186<dl> 1291<dl>
1187 <dt>ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)</dt> 1292 <dt>ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)</dt>
1188 <dt>ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)</dt> 1293 <dt>ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)</dt>
1189 <dd> 1294 <dd>
1190 <p>Configures the watcher to wait for status changes of the given 1295 <p>Configures the watcher to wait for status changes of the given
… …
1274 <p>Initialises and configures the idle watcher - it has no parameters of any 1379 <p>Initialises and configures the idle watcher - it has no parameters of any
1275kind. There is a <code>ev_idle_set</code> macro, but using it is utterly pointless, 1380kind. There is a <code>ev_idle_set</code> macro, but using it is utterly pointless,
1276believe me.</p> 1381believe me.</p>
1277 </dd> 1382 </dd>
1278</dl> 1383</dl>
1279<p>Example: dynamically allocate an <code>ev_idle</code>, start it, and in the 1384<p>Example: Dynamically allocate an <code>ev_idle</code> watcher, start it, and in the
1280callback, free it. Alos, use no error checking, as usual.</p> 1385callback, free it. Also, use no error checking, as usual.</p>
1281<pre> static void 1386<pre> static void
1282 idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents) 1387 idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents)
1283 { 1388 {
1284 free (w); 1389 free (w);
1285 // now do something you wanted to do when the program has 1390 // now do something you wanted to do when the program has
… …
1510 1615
1511 1616
1512 1617
1513 1618
1514</div> 1619</div>
1515<h1 id="OTHER_FUNCTIONS">OTHER FUNCTIONS</h1><p><a href="#TOP" class="toplink">Top</a></p> 1620<h1 id="OTHER_FUNCTIONS">OTHER FUNCTIONS</h1>
1516<div id="OTHER_FUNCTIONS_CONTENT"> 1621<div id="OTHER_FUNCTIONS_CONTENT">
1517<p>There are some other functions of possible interest. Described. Here. Now.</p> 1622<p>There are some other functions of possible interest. Described. Here. Now.</p>
1518<dl> 1623<dl>
1519 <dt>ev_once (loop, int fd, int events, ev_tstamp timeout, callback)</dt> 1624 <dt>ev_once (loop, int fd, int events, ev_tstamp timeout, callback)</dt>
1520 <dd> 1625 <dd>
… …
1567 1672
1568 1673
1569 1674
1570 1675
1571</div> 1676</div>
1572<h1 id="LIBEVENT_EMULATION">LIBEVENT EMULATION</h1><p><a href="#TOP" class="toplink">Top</a></p> 1677<h1 id="LIBEVENT_EMULATION">LIBEVENT EMULATION</h1>
1573<div id="LIBEVENT_EMULATION_CONTENT"> 1678<div id="LIBEVENT_EMULATION_CONTENT">
1574<p>Libev offers a compatibility emulation layer for libevent. It cannot 1679<p>Libev offers a compatibility emulation layer for libevent. It cannot
1575emulate the internals of libevent, so here are some usage hints:</p> 1680emulate the internals of libevent, so here are some usage hints:</p>
1576<dl> 1681<dl>
1577 <dt>* Use it by including &lt;event.h&gt;, as usual.</dt> 1682 <dt>* Use it by including &lt;event.h&gt;, as usual.</dt>
… …
1587 <dt>* The libev emulation is <i>not</i> ABI compatible to libevent, you need 1692 <dt>* The libev emulation is <i>not</i> ABI compatible to libevent, you need
1588to use the libev header file and library.</dt> 1693to use the libev header file and library.</dt>
1589</dl> 1694</dl>
1590 1695
1591</div> 1696</div>
1592<h1 id="C_SUPPORT">C++ SUPPORT</h1><p><a href="#TOP" class="toplink">Top</a></p> 1697<h1 id="C_SUPPORT">C++ SUPPORT</h1>
1593<div id="C_SUPPORT_CONTENT"> 1698<div id="C_SUPPORT_CONTENT">
1594<p>Libev comes with some simplistic wrapper classes for C++ that mainly allow 1699<p>Libev comes with some simplistic wrapper classes for C++ that mainly allow
1595you to use some convinience methods to start/stop watchers and also change 1700you to use some convinience methods to start/stop watchers and also change
1596the callback model to a model using method callbacks on objects.</p> 1701the callback model to a model using method callbacks on objects.</p>
1597<p>To use it,</p> 1702<p>To use it,</p>
… …
1692 1797
1693 1798
1694</pre> 1799</pre>
1695 1800
1696</div> 1801</div>
1697<h1 id="MACRO_MAGIC">MACRO MAGIC</h1><p><a href="#TOP" class="toplink">Top</a></p> 1802<h1 id="MACRO_MAGIC">MACRO MAGIC</h1>
1698<div id="MACRO_MAGIC_CONTENT"> 1803<div id="MACRO_MAGIC_CONTENT">
1699<p>Libev can be compiled with a variety of options, the most fundemantal is 1804<p>Libev can be compiled with a variety of options, the most fundemantal is
1700<code>EV_MULTIPLICITY</code>. This option determines wether (most) functions and 1805<code>EV_MULTIPLICITY</code>. This option determines wether (most) functions and
1701callbacks have an initial <code>struct ev_loop *</code> argument.</p> 1806callbacks have an initial <code>struct ev_loop *</code> argument.</p>
1702<p>To make it easier to write programs that cope with either variant, the 1807<p>To make it easier to write programs that cope with either variant, the
… …
1734 <dd> 1839 <dd>
1735 <p>Similar to the other two macros, this gives you the value of the default 1840 <p>Similar to the other two macros, this gives you the value of the default
1736loop, if multiple loops are supported (&quot;ev loop default&quot;).</p> 1841loop, if multiple loops are supported (&quot;ev loop default&quot;).</p>
1737 </dd> 1842 </dd>
1738</dl> 1843</dl>
1739<p>Example: Declare and initialise a check watcher, working regardless of 1844<p>Example: Declare and initialise a check watcher, utilising the above
1740wether multiple loops are supported or not.</p> 1845macros so it will work regardless of wether multiple loops are supported
1846or not.</p>
1741<pre> static void 1847<pre> static void
1742 check_cb (EV_P_ ev_timer *w, int revents) 1848 check_cb (EV_P_ ev_timer *w, int revents)
1743 { 1849 {
1744 ev_check_stop (EV_A_ w); 1850 ev_check_stop (EV_A_ w);
1745 } 1851 }
… …
1747 ev_check check; 1853 ev_check check;
1748 ev_check_init (&amp;check, check_cb); 1854 ev_check_init (&amp;check, check_cb);
1749 ev_check_start (EV_DEFAULT_ &amp;check); 1855 ev_check_start (EV_DEFAULT_ &amp;check);
1750 ev_loop (EV_DEFAULT_ 0); 1856 ev_loop (EV_DEFAULT_ 0);
1751 1857
1752
1753
1754
1755</pre> 1858</pre>
1756 1859
1757</div> 1860</div>
1758<h1 id="EMBEDDING">EMBEDDING</h1><p><a href="#TOP" class="toplink">Top</a></p> 1861<h1 id="EMBEDDING">EMBEDDING</h1>
1759<div id="EMBEDDING_CONTENT"> 1862<div id="EMBEDDING_CONTENT">
1760<p>Libev can (and often is) directly embedded into host 1863<p>Libev can (and often is) directly embedded into host
1761applications. Examples of applications that embed it include the Deliantra 1864applications. Examples of applications that embed it include the Deliantra
1762Game Server, the EV perl module, the GNU Virtual Private Ethernet (gvpe) 1865Game Server, the EV perl module, the GNU Virtual Private Ethernet (gvpe)
1763and rxvt-unicode.</p> 1866and rxvt-unicode.</p>
… …
1800 ev_vars.h 1903 ev_vars.h
1801 ev_wrap.h 1904 ev_wrap.h
1802 1905
1803 ev_win32.c required on win32 platforms only 1906 ev_win32.c required on win32 platforms only
1804 1907
1805 ev_select.c only when select backend is enabled (which is by default) 1908 ev_select.c only when select backend is enabled (which is enabled by default)
1806 ev_poll.c only when poll backend is enabled (disabled by default) 1909 ev_poll.c only when poll backend is enabled (disabled by default)
1807 ev_epoll.c only when the epoll backend is enabled (disabled by default) 1910 ev_epoll.c only when the epoll backend is enabled (disabled by default)
1808 ev_kqueue.c only when the kqueue backend is enabled (disabled by default) 1911 ev_kqueue.c only when the kqueue backend is enabled (disabled by default)
1809 ev_port.c only when the solaris port backend is enabled (disabled by default) 1912 ev_port.c only when the solaris port backend is enabled (disabled by default)
1810 1913
… …
1937 </dd> 2040 </dd>
1938 <dt>EV_USE_DEVPOLL</dt> 2041 <dt>EV_USE_DEVPOLL</dt>
1939 <dd> 2042 <dd>
1940 <p>reserved for future expansion, works like the USE symbols above.</p> 2043 <p>reserved for future expansion, works like the USE symbols above.</p>
1941 </dd> 2044 </dd>
2045 <dt>EV_USE_INOTIFY</dt>
2046 <dd>
2047 <p>If defined to be <code>1</code>, libev will compile in support for the Linux inotify
2048interface to speed up <code>ev_stat</code> watchers. Its actual availability will
2049be detected at runtime.</p>
2050 </dd>
1942 <dt>EV_H</dt> 2051 <dt>EV_H</dt>
1943 <dd> 2052 <dd>
1944 <p>The name of the <cite>ev.h</cite> header file used to include it. The default if 2053 <p>The name of the <cite>ev.h</cite> header file used to include it. The default if
1945undefined 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 2054undefined 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
1946can be used to virtually rename the <cite>ev.h</cite> header file in case of conflicts.</p> 2055can be used to virtually rename the <cite>ev.h</cite> header file in case of conflicts.</p>
… …
2001 <dt>EV_PID_HASHSIZE</dt> 2110 <dt>EV_PID_HASHSIZE</dt>
2002 <dd> 2111 <dd>
2003 <p><code>ev_child</code> watchers use a small hash table to distribute workload by 2112 <p><code>ev_child</code> watchers use a small hash table to distribute workload by
2004pid. The default size is <code>16</code> (or <code>1</code> with <code>EV_MINIMAL</code>), usually more 2113pid. The default size is <code>16</code> (or <code>1</code> with <code>EV_MINIMAL</code>), usually more
2005than enough. If you need to manage thousands of children you might want to 2114than enough. If you need to manage thousands of children you might want to
2006increase this value.</p> 2115increase this value (<i>must</i> be a power of two).</p>
2116 </dd>
2117 <dt>EV_INOTIFY_HASHSIZE</dt>
2118 <dd>
2119 <p><code>ev_staz</code> watchers use a small hash table to distribute workload by
2120inotify watch id. The default size is <code>16</code> (or <code>1</code> with <code>EV_MINIMAL</code>),
2121usually more than enough. If you need to manage thousands of <code>ev_stat</code>
2122watchers you might want to increase this value (<i>must</i> be a power of
2123two).</p>
2007 </dd> 2124 </dd>
2008 <dt>EV_COMMON</dt> 2125 <dt>EV_COMMON</dt>
2009 <dd> 2126 <dd>
2010 <p>By default, all watchers have a <code>void *data</code> member. By redefining 2127 <p>By default, all watchers have a <code>void *data</code> member. By redefining
2011this macro to a something else you can include more and other types of 2128this macro to a something else you can include more and other types of
… …
2038the <cite>libev/</cite> subdirectory and includes them in the <cite>EV/EVAPI.h</cite> (public 2155the <cite>libev/</cite> subdirectory and includes them in the <cite>EV/EVAPI.h</cite> (public
2039interface) and <cite>EV.xs</cite> (implementation) files. Only the <cite>EV.xs</cite> file 2156interface) and <cite>EV.xs</cite> (implementation) files. Only the <cite>EV.xs</cite> file
2040will be compiled. It is pretty complex because it provides its own header 2157will be compiled. It is pretty complex because it provides its own header
2041file.</p> 2158file.</p>
2042 <p>The usage in rxvt-unicode is simpler. It has a <cite>ev_cpp.h</cite> header file 2159 <p>The usage in rxvt-unicode is simpler. It has a <cite>ev_cpp.h</cite> header file
2043that everybody includes and which overrides some autoconf choices:</p> 2160that everybody includes and which overrides some configure choices:</p>
2161<pre> #define EV_MINIMAL 1
2044<pre> #define EV_USE_POLL 0 2162 #define EV_USE_POLL 0
2045 #define EV_MULTIPLICITY 0 2163 #define EV_MULTIPLICITY 0
2046 #define EV_PERIODICS 0 2164 #define EV_PERIODIC_ENABLE 0
2165 #define EV_STAT_ENABLE 0
2166 #define EV_FORK_ENABLE 0
2047 #define EV_CONFIG_H &lt;config.h&gt; 2167 #define EV_CONFIG_H &lt;config.h&gt;
2168 #define EV_MINPRI 0
2169 #define EV_MAXPRI 0
2048 2170
2049 #include &quot;ev++.h&quot; 2171 #include &quot;ev++.h&quot;
2050 2172
2051</pre> 2173</pre>
2052 <p>And a <cite>ev_cpp.C</cite> implementation file that contains libev proper and is compiled:</p> 2174 <p>And a <cite>ev_cpp.C</cite> implementation file that contains libev proper and is compiled:</p>
… …
2057 2179
2058 2180
2059</pre> 2181</pre>
2060 2182
2061</div> 2183</div>
2062<h1 id="COMPLEXITIES">COMPLEXITIES</h1><p><a href="#TOP" class="toplink">Top</a></p> 2184<h1 id="COMPLEXITIES">COMPLEXITIES</h1>
2063<div id="COMPLEXITIES_CONTENT"> 2185<div id="COMPLEXITIES_CONTENT">
2064 <p>In this section the complexities of (many of) the algorithms used inside 2186 <p>In this section the complexities of (many of) the algorithms used inside
2065libev will be explained. For complexity discussions about backends see the 2187libev will be explained. For complexity discussions about backends see the
2066documentation for <code>ev_default_init</code>.</p> 2188documentation for <code>ev_default_init</code>.</p>
2067 <p> 2189 <p>
2068 <dl> 2190 <dl>
2069 <dt>Starting and stopping timer/periodic watchers: O(log skipped_other_timers)</dt> 2191 <dt>Starting and stopping timer/periodic watchers: O(log skipped_other_timers)</dt>
2070 <dt>Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)</dt> 2192 <dt>Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)</dt>
2071 <dt>Starting io/check/prepare/idle/signal/child watchers: O(1)</dt> 2193 <dt>Starting io/check/prepare/idle/signal/child watchers: O(1)</dt>
2072 <dt>Stopping check/prepare/idle watchers: O(1)</dt> 2194 <dt>Stopping check/prepare/idle watchers: O(1)</dt>
2073 <dt>Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % 16))</dt> 2195 <dt>Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))</dt>
2074 <dt>Finding the next timer per loop iteration: O(1)</dt> 2196 <dt>Finding the next timer per loop iteration: O(1)</dt>
2075 <dt>Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)</dt> 2197 <dt>Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)</dt>
2076 <dt>Activating one watcher: O(1)</dt> 2198 <dt>Activating one watcher: O(1)</dt>
2077 </dl> 2199 </dl>
2078 </p> 2200 </p>
… …
2080 2202
2081 2203
2082 2204
2083 2205
2084</div> 2206</div>
2085<h1 id="AUTHOR">AUTHOR</h1><p><a href="#TOP" class="toplink">Top</a></p> 2207<h1 id="AUTHOR">AUTHOR</h1>
2086<div id="AUTHOR_CONTENT"> 2208<div id="AUTHOR_CONTENT">
2087 <p>Marc Lehmann &lt;libev@schmorp.de&gt;.</p> 2209 <p>Marc Lehmann &lt;libev@schmorp.de&gt;.</p>
2088 2210
2089</div> 2211</div>
2090</div></body> 2212</div></body>

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