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4<head> 4<head>
5 <title>libev</title> 5 <title>libev</title>
6 <meta name="description" content="Pod documentation for libev" /> 6 <meta name="description" content="Pod documentation for libev" />
7 <meta name="inputfile" content="&lt;standard input&gt;" /> 7 <meta name="inputfile" content="&lt;standard input&gt;" />
8 <meta name="outputfile" content="&lt;standard output&gt;" /> 8 <meta name="outputfile" content="&lt;standard output&gt;" />
9 <meta name="created" content="Tue Nov 27 21:14:27 2007" /> 9 <meta name="created" content="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> /* this is the only header you need */
72 #include &lt;ev.h&gt; 72<pre> #include &lt;ev.h&gt;
73 73
74 /* what follows is a fully working example program */ 74</pre>
75
76</div>
77<h1 id="EXAMPLE_PROGRAM">EXAMPLE PROGRAM</h1>
78<div id="EXAMPLE_PROGRAM_CONTENT">
79<pre> #include &lt;ev.h&gt;
80
75 ev_io stdin_watcher; 81 ev_io stdin_watcher;
76 ev_timer timeout_watcher; 82 ev_timer timeout_watcher;
77 83
78 /* called when data readable on stdin */ 84 /* called when data readable on stdin */
79 static void 85 static void
… …
111 } 117 }
112 118
113</pre> 119</pre>
114 120
115</div> 121</div>
116<h1 id="DESCRIPTION">DESCRIPTION</h1><p><a href="#TOP" class="toplink">Top</a></p> 122<h1 id="DESCRIPTION">DESCRIPTION</h1>
117<div id="DESCRIPTION_CONTENT"> 123<div id="DESCRIPTION_CONTENT">
118<p>Libev is an event loop: you register interest in certain events (such as a 124<p>Libev is an event loop: you register interest in certain events (such as a
119file descriptor being readable or a timeout occuring), and it will manage 125file descriptor being readable or a timeout occuring), and it will manage
120these event sources and provide your program with events.</p> 126these event sources and provide your program with events.</p>
121<p>To do this, it must take more or less complete control over your process 127<p>To do this, it must take more or less complete control over your process
… …
125watchers</i>, which are relatively small C structures you initialise with the 131watchers</i>, which are relatively small C structures you initialise with the
126details of the event, and then hand it over to libev by <i>starting</i> the 132details of the event, and then hand it over to libev by <i>starting</i> the
127watcher.</p> 133watcher.</p>
128 134
129</div> 135</div>
130<h1 id="FEATURES">FEATURES</h1><p><a href="#TOP" class="toplink">Top</a></p> 136<h1 id="FEATURES">FEATURES</h1>
131<div id="FEATURES_CONTENT"> 137<div id="FEATURES_CONTENT">
132<p>Libev supports select, poll, the linux-specific epoll and the bsd-specific 138<p>Libev supports <code>select</code>, <code>poll</code>, the Linux-specific <code>epoll</code>, the
133kqueue mechanisms for file descriptor events, relative timers, absolute 139BSD-specific <code>kqueue</code> and the Solaris-specific event port mechanisms
134timers with customised rescheduling, signal events, process status change 140for file descriptor events (<code>ev_io</code>), the Linux <code>inotify</code> interface
135events (related to SIGCHLD), and event watchers dealing with the event 141(for <code>ev_stat</code>), relative timers (<code>ev_timer</code>), absolute timers
136loop 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
137fast (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
138it to libevent for example).</p> 150for example).</p>
139 151
140</div> 152</div>
141<h1 id="CONVENTIONS">CONVENTIONS</h1><p><a href="#TOP" class="toplink">Top</a></p> 153<h1 id="CONVENTIONS">CONVENTIONS</h1>
142<div id="CONVENTIONS_CONTENT"> 154<div id="CONVENTIONS_CONTENT">
143<p>Libev is very configurable. In this manual the default configuration 155<p>Libev is very configurable. In this manual the default configuration will
144will be described, which supports multiple event loops. For more info 156be described, which supports multiple event loops. For more info about
145about various configuration options please have a look at the file 157various configuration options please have a look at <strong>EMBED</strong> section in
146<cite>README.embed</cite> in the libev distribution. If libev was configured without 158this manual. If libev was configured without support for multiple event
147support for multiple event loops, then all functions taking an initial 159loops, then all functions taking an initial argument of name <code>loop</code>
148argument of name <code>loop</code> (which is always of type <code>struct ev_loop *</code>) 160(which is always of type <code>struct ev_loop *</code>) will not have this argument.</p>
149will not have this argument.</p>
150 161
151</div> 162</div>
152<h1 id="TIME_REPRESENTATION">TIME REPRESENTATION</h1><p><a href="#TOP" class="toplink">Top</a></p> 163<h1 id="TIME_REPRESENTATION">TIME REPRESENTATION</h1>
153<div id="TIME_REPRESENTATION_CONTENT"> 164<div id="TIME_REPRESENTATION_CONTENT">
154<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
155(fractional) number of seconds since the (POSIX) epoch (somewhere near 166(fractional) number of seconds since the (POSIX) epoch (somewhere near
156the 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
157called <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
158to 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
159it, you should treat it as such.</p> 170it, you should treat it as such.</p>
160 171
161</div> 172</div>
162<h1 id="GLOBAL_FUNCTIONS">GLOBAL FUNCTIONS</h1><p><a href="#TOP" class="toplink">Top</a></p> 173<h1 id="GLOBAL_FUNCTIONS">GLOBAL FUNCTIONS</h1>
163<div id="GLOBAL_FUNCTIONS_CONTENT"> 174<div id="GLOBAL_FUNCTIONS_CONTENT">
164<p>These functions can be called anytime, even before initialising the 175<p>These functions can be called anytime, even before initialising the
165library in any way.</p> 176library in any way.</p>
166<dl> 177<dl>
167 <dt>ev_tstamp ev_time ()</dt> 178 <dt>ev_tstamp ev_time ()</dt>
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180version of the library your program was compiled against.</p> 191version of the library your program was compiled against.</p>
181 <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,
182as this indicates an incompatible change. Minor versions are usually 193as this indicates an incompatible change. Minor versions are usually
183compatible to older versions, so a larger minor version alone is usually 194compatible to older versions, so a larger minor version alone is usually
184not a problem.</p> 195not a problem.</p>
185 <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
186version:</p> 197version.</p>
187<pre> assert ((&quot;libev version mismatch&quot;, 198<pre> assert ((&quot;libev version mismatch&quot;,
188 ev_version_major () == EV_VERSION_MAJOR 199 ev_version_major () == EV_VERSION_MAJOR
189 &amp;&amp; ev_version_minor () &gt;= EV_VERSION_MINOR)); 200 &amp;&amp; ev_version_minor () &gt;= EV_VERSION_MINOR));
190 201
191</pre> 202</pre>
… …
219might 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
220<code>ev_embeddable_backends () &amp; ev_supported_backends ()</code>, likewise for 231<code>ev_embeddable_backends () &amp; ev_supported_backends ()</code>, likewise for
221recommended ones.</p> 232recommended ones.</p>
222 <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>
223 </dd> 234 </dd>
224 <dt>ev_set_allocator (void *(*cb)(void *ptr, size_t size))</dt> 235 <dt>ev_set_allocator (void *(*cb)(void *ptr, long size))</dt>
225 <dd> 236 <dd>
226 <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
227identical to the realloc C function). It is used to allocate and free 238semantics is identical - to the realloc C function). It is used to
228memory (no surprises here). If it returns zero when memory needs to be 239allocate and free memory (no surprises here). If it returns zero when
229allocated, the library might abort or take some potentially destructive 240memory needs to be allocated, the library might abort or take some
230action. The default is your system realloc function.</p> 241potentially destructive action. The default is your system realloc
242function.</p>
231 <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,
232free 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,
233or 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>
234 <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
235retries: better than mine).</p> 247retries).</p>
236<pre> static void * 248<pre> static void *
237 persistent_realloc (void *ptr, size_t size) 249 persistent_realloc (void *ptr, size_t size)
238 { 250 {
239 for (;;) 251 for (;;)
240 { 252 {
… …
259indicating the system call or subsystem causing the problem. If this 271indicating the system call or subsystem causing the problem. If this
260callback 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
261matter what, when it returns. That is, libev will generally retry the 273matter what, when it returns. That is, libev will generally retry the
262requested 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
263(such as abort).</p> 275(such as abort).</p>
264 <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>
265<pre> static void 277<pre> static void
266 fatal_error (const char *msg) 278 fatal_error (const char *msg)
267 { 279 {
268 perror (msg); 280 perror (msg);
269 abort (); 281 abort ();
… …
275</pre> 287</pre>
276 </dd> 288 </dd>
277</dl> 289</dl>
278 290
279</div> 291</div>
280<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>
281<div id="FUNCTIONS_CONTROLLING_THE_EVENT_LOOP-2"> 293<div id="FUNCTIONS_CONTROLLING_THE_EVENT_LOOP-2">
282<p>An event loop is described by a <code>struct ev_loop *</code>. The library knows two 294<p>An event loop is described by a <code>struct ev_loop *</code>. The library knows two
283types of such loops, the <i>default</i> loop, which supports signals and child 295types of such loops, the <i>default</i> loop, which supports signals and child
284events, and dynamically created loops which do not.</p> 296events, and dynamically created loops which do not.</p>
285<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
… …
313or 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
314<code>LIBEV_FLAGS</code>. Otherwise (the default), this environment variable will 326<code>LIBEV_FLAGS</code>. Otherwise (the default), this environment variable will
315override 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
316useful 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
317around 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>
318 </dd> 347 </dd>
319 <dt><code>EVBACKEND_SELECT</code> (value 1, portable select backend)</dt> 348 <dt><code>EVBACKEND_SELECT</code> (value 1, portable select backend)</dt>
320 <dd> 349 <dd>
321 <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
322libev 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,
… …
405 <dd> 434 <dd>
406 <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
407always distinct from the default loop. Unlike the default loop, it cannot 436always distinct from the default loop. Unlike the default loop, it cannot
408handle signal and child watchers, and attempts to do so will be greeted by 437handle signal and child watchers, and attempts to do so will be greeted by
409undefined behaviour (or a failed assertion if assertions are enabled).</p> 438undefined behaviour (or a failed assertion if assertions are enabled).</p>
410 <p>Example: try to create a event loop that uses epoll and nothing else.</p> 439 <p>Example: Try to create a event loop that uses epoll and nothing else.</p>
411<pre> struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV); 440<pre> struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV);
412 if (!epoller) 441 if (!epoller)
413 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;);
414 443
415</pre> 444</pre>
… …
508 be handled here by queueing them when their watcher gets executed. 537 be handled here by queueing them when their watcher gets executed.
509 - 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
510 were used, return, otherwise continue with step *. 539 were used, return, otherwise continue with step *.
511 540
512</pre> 541</pre>
513 <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
514anymore.</p> 543anymore.</p>
515<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
516 ... 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..)
517 ev_loop (my_loop, 0); 546 ev_loop (my_loop, 0);
518 ... jobs done. yeah! 547 ... jobs done. yeah!
… …
537example, 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
538visible 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
539no 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
540way 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
541libraries. 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>
542 <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>
543running when nothing else is active.</p> 572running when nothing else is active.</p>
544<pre> struct dv_signal exitsig; 573<pre> struct ev_signal exitsig;
545 ev_signal_init (&amp;exitsig, sig_cb, SIGINT); 574 ev_signal_init (&amp;exitsig, sig_cb, SIGINT);
546 ev_signal_start (myloop, &amp;exitsig); 575 ev_signal_start (loop, &amp;exitsig);
547 evf_unref (myloop); 576 evf_unref (loop);
548 577
549</pre> 578</pre>
550 <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>
551<pre> ev_ref (myloop); 580<pre> ev_ref (loop);
552 ev_signal_stop (myloop, &amp;exitsig); 581 ev_signal_stop (loop, &amp;exitsig);
553 582
554</pre> 583</pre>
555 </dd> 584 </dd>
556</dl> 585</dl>
557 586
558 587
559 588
560 589
561 590
562</div> 591</div>
563<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>
564<div id="ANATOMY_OF_A_WATCHER_CONTENT"> 593<div id="ANATOMY_OF_A_WATCHER_CONTENT">
565<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
566interest 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
567become 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>
568<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)
… …
731events 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
732is 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
733<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
734libev (e.g. you cnanot <code>free ()</code> it).</p> 763libev (e.g. you cnanot <code>free ()</code> it).</p>
735 </dd> 764 </dd>
736 <dt>callback = ev_cb (ev_TYPE *watcher)</dt> 765 <dt>callback ev_cb (ev_TYPE *watcher)</dt>
737 <dd> 766 <dd>
738 <p>Returns the callback currently set on the watcher.</p> 767 <p>Returns the callback currently set on the watcher.</p>
739 </dd> 768 </dd>
740 <dt>ev_cb_set (ev_TYPE *watcher, callback)</dt> 769 <dt>ev_cb_set (ev_TYPE *watcher, callback)</dt>
741 <dd> 770 <dd>
… …
773 struct my_io *w = (struct my_io *)w_; 802 struct my_io *w = (struct my_io *)w_;
774 ... 803 ...
775 } 804 }
776 805
777</pre> 806</pre>
778<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
779have 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 }
780 817
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;
781 822
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 }
782 829
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 }
783 836
784 837
838
839
840</pre>
841
785</div> 842</div>
786<h1 id="WATCHER_TYPES">WATCHER TYPES</h1><p><a href="#TOP" class="toplink">Top</a></p> 843<h1 id="WATCHER_TYPES">WATCHER TYPES</h1>
787<div id="WATCHER_TYPES_CONTENT"> 844<div id="WATCHER_TYPES_CONTENT">
788<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
789information given in the last section. Any initialisation/set macros, 846information given in the last section. Any initialisation/set macros,
790functions and members specific to the watcher type are explained.</p> 847functions and members specific to the watcher type are explained.</p>
791<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,
… …
851 <dt>int events [read-only]</dt> 908 <dt>int events [read-only]</dt>
852 <dd> 909 <dd>
853 <p>The events being watched.</p> 910 <p>The events being watched.</p>
854 </dd> 911 </dd>
855</dl> 912</dl>
856<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
857readable, but only once. Since it is likely line-buffered, you could 914readable, but only once. Since it is likely line-buffered, you could
858attempt to read a whole line in the callback:</p> 915attempt to read a whole line in the callback.</p>
859<pre> static void 916<pre> static void
860 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)
861 { 918 {
862 ev_io_stop (loop, w); 919 ev_io_stop (loop, w);
863 .. 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
… …
912 </dd> 969 </dd>
913 <dt>ev_timer_again (loop)</dt> 970 <dt>ev_timer_again (loop)</dt>
914 <dd> 971 <dd>
915 <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
916repeating. The exact semantics are:</p> 973repeating. The exact semantics are:</p>
974 <p>If the timer is pending, its pending status is cleared.</p>
917 <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>
918 <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
919value), 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>
920 <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
921example: 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
922idle 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
923say, 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
924this 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
925<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
926you 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
927socket, 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
928need be.</p> 986automatically restart it if need be.</p>
929 <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>
930and 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>
931<pre> ev_timer_init (timer, callback, 0., 5.); 989<pre> ev_timer_init (timer, callback, 0., 5.);
932 ev_timer_again (loop, timer); 990 ev_timer_again (loop, timer);
933 ... 991 ...
934 timer-&gt;again = 17.; 992 timer-&gt;again = 17.;
935 ev_timer_again (loop, timer); 993 ev_timer_again (loop, timer);
936 ... 994 ...
937 timer-&gt;again = 10.; 995 timer-&gt;again = 10.;
938 ev_timer_again (loop, timer); 996 ev_timer_again (loop, timer);
939 997
940</pre> 998</pre>
941 <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
942to modify its timeout value.</p> 1000you want to modify its timeout value.</p>
943 </dd> 1001 </dd>
944 <dt>ev_tstamp repeat [read-write]</dt> 1002 <dt>ev_tstamp repeat [read-write]</dt>
945 <dd> 1003 <dd>
946 <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
947or <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),
948which is also when any modifications are taken into account.</p> 1006which is also when any modifications are taken into account.</p>
949 </dd> 1007 </dd>
950</dl> 1008</dl>
951<p>Example: create a timer that fires after 60 seconds.</p> 1009<p>Example: Create a timer that fires after 60 seconds.</p>
952<pre> static void 1010<pre> static void
953 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)
954 { 1012 {
955 .. one minute over, w is actually stopped right here 1013 .. one minute over, w is actually stopped right here
956 } 1014 }
… …
958 struct ev_timer mytimer; 1016 struct ev_timer mytimer;
959 ev_timer_init (&amp;mytimer, one_minute_cb, 60., 0.); 1017 ev_timer_init (&amp;mytimer, one_minute_cb, 60., 0.);
960 ev_timer_start (loop, &amp;mytimer); 1018 ev_timer_start (loop, &amp;mytimer);
961 1019
962</pre> 1020</pre>
963<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
964inactivity.</p> 1022inactivity.</p>
965<pre> static void 1023<pre> static void
966 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)
967 { 1025 {
968 .. ten seconds without any activity 1026 .. ten seconds without any activity
… …
1084 <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
1085switched 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
1086the 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>
1087 </dd> 1145 </dd>
1088</dl> 1146</dl>
1089<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
1090system clock is divisible by 3600. The callback invocation times have 1148system clock is divisible by 3600. The callback invocation times have
1091potentially a lot of jittering, but good long-term stability.</p> 1149potentially a lot of jittering, but good long-term stability.</p>
1092<pre> static void 1150<pre> static void
1093 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)
1094 { 1152 {
… …
1098 struct ev_periodic hourly_tick; 1156 struct ev_periodic hourly_tick;
1099 ev_periodic_init (&amp;hourly_tick, clock_cb, 0., 3600., 0); 1157 ev_periodic_init (&amp;hourly_tick, clock_cb, 0., 3600., 0);
1100 ev_periodic_start (loop, &amp;hourly_tick); 1158 ev_periodic_start (loop, &amp;hourly_tick);
1101 1159
1102</pre> 1160</pre>
1103<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>
1104<pre> #include &lt;math.h&gt; 1162<pre> #include &lt;math.h&gt;
1105 1163
1106 static ev_tstamp 1164 static ev_tstamp
1107 my_scheduler_cb (struct ev_periodic *w, ev_tstamp now) 1165 my_scheduler_cb (struct ev_periodic *w, ev_tstamp now)
1108 { 1166 {
… …
1110 } 1168 }
1111 1169
1112 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);
1113 1171
1114</pre> 1172</pre>
1115<p>Example: call a callback every hour, starting now:</p> 1173<p>Example: Call a callback every hour, starting now:</p>
1116<pre> struct ev_periodic hourly_tick; 1174<pre> struct ev_periodic hourly_tick;
1117 ev_periodic_init (&amp;hourly_tick, clock_cb, 1175 ev_periodic_init (&amp;hourly_tick, clock_cb,
1118 fmod (ev_now (loop), 3600.), 3600., 0); 1176 fmod (ev_now (loop), 3600.), 3600., 0);
1119 ev_periodic_start (loop, &amp;hourly_tick); 1177 ev_periodic_start (loop, &amp;hourly_tick);
1120 1178
… …
1181 <dd> 1239 <dd>
1182 <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
1183<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>
1184 </dd> 1242 </dd>
1185</dl> 1243</dl>
1186<p>Example: try to exit cleanly on SIGINT and SIGTERM.</p> 1244<p>Example: Try to exit cleanly on SIGINT and SIGTERM.</p>
1187<pre> static void 1245<pre> static void
1188 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)
1189 { 1247 {
1190 ev_unloop (loop, EVUNLOOP_ALL); 1248 ev_unloop (loop, EVUNLOOP_ALL);
1191 } 1249 }
… …
1208<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
1209not 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
1210not 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
1211otherwise 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
1212the 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>
1213<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
1214calls <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
1215can specify a recommended polling interval for this case. If you specify 1275can specify a recommended polling interval for this case. If you specify
1216a 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,
1217unspecified 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
1218five seconds, although this might change dynamically). Libev will also 1278five seconds, although this might change dynamically). Libev will also
1219impose 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
1220usually overkill.</p> 1280usually overkill.</p>
1221<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,
1222as even with OS-supported change notifications, this can be 1282as even with OS-supported change notifications, this can be
1223resource-intensive.</p> 1283resource-intensive.</p>
1224<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
1225if 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>
1226<dl> 1291<dl>
1227 <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>
1228 <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>
1229 <dd> 1294 <dd>
1230 <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
… …
1314 <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
1315kind. 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,
1316believe me.</p> 1381believe me.</p>
1317 </dd> 1382 </dd>
1318</dl> 1383</dl>
1319<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
1320callback, free it. Alos, use no error checking, as usual.</p> 1385callback, free it. Also, use no error checking, as usual.</p>
1321<pre> static void 1386<pre> static void
1322 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)
1323 { 1388 {
1324 free (w); 1389 free (w);
1325 // now do something you wanted to do when the program has 1390 // now do something you wanted to do when the program has
… …
1550 1615
1551 1616
1552 1617
1553 1618
1554</div> 1619</div>
1555<h1 id="OTHER_FUNCTIONS">OTHER FUNCTIONS</h1><p><a href="#TOP" class="toplink">Top</a></p> 1620<h1 id="OTHER_FUNCTIONS">OTHER FUNCTIONS</h1>
1556<div id="OTHER_FUNCTIONS_CONTENT"> 1621<div id="OTHER_FUNCTIONS_CONTENT">
1557<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>
1558<dl> 1623<dl>
1559 <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>
1560 <dd> 1625 <dd>
… …
1607 1672
1608 1673
1609 1674
1610 1675
1611</div> 1676</div>
1612<h1 id="LIBEVENT_EMULATION">LIBEVENT EMULATION</h1><p><a href="#TOP" class="toplink">Top</a></p> 1677<h1 id="LIBEVENT_EMULATION">LIBEVENT EMULATION</h1>
1613<div id="LIBEVENT_EMULATION_CONTENT"> 1678<div id="LIBEVENT_EMULATION_CONTENT">
1614<p>Libev offers a compatibility emulation layer for libevent. It cannot 1679<p>Libev offers a compatibility emulation layer for libevent. It cannot
1615emulate the internals of libevent, so here are some usage hints:</p> 1680emulate the internals of libevent, so here are some usage hints:</p>
1616<dl> 1681<dl>
1617 <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>
… …
1627 <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
1628to use the libev header file and library.</dt> 1693to use the libev header file and library.</dt>
1629</dl> 1694</dl>
1630 1695
1631</div> 1696</div>
1632<h1 id="C_SUPPORT">C++ SUPPORT</h1><p><a href="#TOP" class="toplink">Top</a></p> 1697<h1 id="C_SUPPORT">C++ SUPPORT</h1>
1633<div id="C_SUPPORT_CONTENT"> 1698<div id="C_SUPPORT_CONTENT">
1634<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
1635you 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
1636the callback model to a model using method callbacks on objects.</p> 1701the callback model to a model using method callbacks on objects.</p>
1637<p>To use it,</p> 1702<p>To use it,</p>
… …
1732 1797
1733 1798
1734</pre> 1799</pre>
1735 1800
1736</div> 1801</div>
1737<h1 id="MACRO_MAGIC">MACRO MAGIC</h1><p><a href="#TOP" class="toplink">Top</a></p> 1802<h1 id="MACRO_MAGIC">MACRO MAGIC</h1>
1738<div id="MACRO_MAGIC_CONTENT"> 1803<div id="MACRO_MAGIC_CONTENT">
1739<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
1740<code>EV_MULTIPLICITY</code>. This option determines wether (most) functions and 1805<code>EV_MULTIPLICITY</code>. This option determines wether (most) functions and
1741callbacks have an initial <code>struct ev_loop *</code> argument.</p> 1806callbacks have an initial <code>struct ev_loop *</code> argument.</p>
1742<p>To make it easier to write programs that cope with either variant, the 1807<p>To make it easier to write programs that cope with either variant, the
… …
1774 <dd> 1839 <dd>
1775 <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
1776loop, if multiple loops are supported (&quot;ev loop default&quot;).</p> 1841loop, if multiple loops are supported (&quot;ev loop default&quot;).</p>
1777 </dd> 1842 </dd>
1778</dl> 1843</dl>
1779<p>Example: Declare and initialise a check watcher, working regardless of 1844<p>Example: Declare and initialise a check watcher, utilising the above
1780wether multiple loops are supported or not.</p> 1845macros so it will work regardless of wether multiple loops are supported
1846or not.</p>
1781<pre> static void 1847<pre> static void
1782 check_cb (EV_P_ ev_timer *w, int revents) 1848 check_cb (EV_P_ ev_timer *w, int revents)
1783 { 1849 {
1784 ev_check_stop (EV_A_ w); 1850 ev_check_stop (EV_A_ w);
1785 } 1851 }
… …
1787 ev_check check; 1853 ev_check check;
1788 ev_check_init (&amp;check, check_cb); 1854 ev_check_init (&amp;check, check_cb);
1789 ev_check_start (EV_DEFAULT_ &amp;check); 1855 ev_check_start (EV_DEFAULT_ &amp;check);
1790 ev_loop (EV_DEFAULT_ 0); 1856 ev_loop (EV_DEFAULT_ 0);
1791 1857
1792
1793
1794
1795</pre> 1858</pre>
1796 1859
1797</div> 1860</div>
1798<h1 id="EMBEDDING">EMBEDDING</h1><p><a href="#TOP" class="toplink">Top</a></p> 1861<h1 id="EMBEDDING">EMBEDDING</h1>
1799<div id="EMBEDDING_CONTENT"> 1862<div id="EMBEDDING_CONTENT">
1800<p>Libev can (and often is) directly embedded into host 1863<p>Libev can (and often is) directly embedded into host
1801applications. Examples of applications that embed it include the Deliantra 1864applications. Examples of applications that embed it include the Deliantra
1802Game Server, the EV perl module, the GNU Virtual Private Ethernet (gvpe) 1865Game Server, the EV perl module, the GNU Virtual Private Ethernet (gvpe)
1803and rxvt-unicode.</p> 1866and rxvt-unicode.</p>
… …
1840 ev_vars.h 1903 ev_vars.h
1841 ev_wrap.h 1904 ev_wrap.h
1842 1905
1843 ev_win32.c required on win32 platforms only 1906 ev_win32.c required on win32 platforms only
1844 1907
1845 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)
1846 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)
1847 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)
1848 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)
1849 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)
1850 1913
… …
1977 </dd> 2040 </dd>
1978 <dt>EV_USE_DEVPOLL</dt> 2041 <dt>EV_USE_DEVPOLL</dt>
1979 <dd> 2042 <dd>
1980 <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>
1981 </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>
1982 <dt>EV_H</dt> 2051 <dt>EV_H</dt>
1983 <dd> 2052 <dd>
1984 <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
1985undefined 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
1986can 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>
… …
2041 <dt>EV_PID_HASHSIZE</dt> 2110 <dt>EV_PID_HASHSIZE</dt>
2042 <dd> 2111 <dd>
2043 <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
2044pid. 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
2045than 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
2046increase 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>
2047 </dd> 2124 </dd>
2048 <dt>EV_COMMON</dt> 2125 <dt>EV_COMMON</dt>
2049 <dd> 2126 <dd>
2050 <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
2051this 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
… …
2078the <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
2079interface) 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
2080will 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
2081file.</p> 2158file.</p>
2082 <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
2083that 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
2084<pre> #define EV_USE_POLL 0 2162 #define EV_USE_POLL 0
2085 #define EV_MULTIPLICITY 0 2163 #define EV_MULTIPLICITY 0
2086 #define EV_PERIODICS 0 2164 #define EV_PERIODIC_ENABLE 0
2165 #define EV_STAT_ENABLE 0
2166 #define EV_FORK_ENABLE 0
2087 #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
2088 2170
2089 #include &quot;ev++.h&quot; 2171 #include &quot;ev++.h&quot;
2090 2172
2091</pre> 2173</pre>
2092 <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>
… …
2097 2179
2098 2180
2099</pre> 2181</pre>
2100 2182
2101</div> 2183</div>
2102<h1 id="COMPLEXITIES">COMPLEXITIES</h1><p><a href="#TOP" class="toplink">Top</a></p> 2184<h1 id="COMPLEXITIES">COMPLEXITIES</h1>
2103<div id="COMPLEXITIES_CONTENT"> 2185<div id="COMPLEXITIES_CONTENT">
2104 <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
2105libev will be explained. For complexity discussions about backends see the 2187libev will be explained. For complexity discussions about backends see the
2106documentation for <code>ev_default_init</code>.</p> 2188documentation for <code>ev_default_init</code>.</p>
2107 <p> 2189 <p>
2108 <dl> 2190 <dl>
2109 <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>
2110 <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>
2111 <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>
2112 <dt>Stopping check/prepare/idle watchers: O(1)</dt> 2194 <dt>Stopping check/prepare/idle watchers: O(1)</dt>
2113 <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>
2114 <dt>Finding the next timer per loop iteration: O(1)</dt> 2196 <dt>Finding the next timer per loop iteration: O(1)</dt>
2115 <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>
2116 <dt>Activating one watcher: O(1)</dt> 2198 <dt>Activating one watcher: O(1)</dt>
2117 </dl> 2199 </dl>
2118 </p> 2200 </p>
… …
2120 2202
2121 2203
2122 2204
2123 2205
2124</div> 2206</div>
2125<h1 id="AUTHOR">AUTHOR</h1><p><a href="#TOP" class="toplink">Top</a></p> 2207<h1 id="AUTHOR">AUTHOR</h1>
2126<div id="AUTHOR_CONTENT"> 2208<div id="AUTHOR_CONTENT">
2127 <p>Marc Lehmann &lt;libev@schmorp.de&gt;.</p> 2209 <p>Marc Lehmann &lt;libev@schmorp.de&gt;.</p>
2128 2210
2129</div> 2211</div>
2130</div></body> 2212</div></body>

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