ViewVC Help
View File | Revision Log | Show Annotations | Download File
/cvs/libev/ev.html
(Generate patch)

Comparing libev/ev.html (file contents):
Revision 1.21 by root, Mon Nov 12 09:01:12 2007 UTC vs.
Revision 1.24 by root, Mon Nov 12 09:07:10 2007 UTC

… …
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="Mon Nov 12 10:01:12 2007" /> 9 <meta name="created" content="Mon Nov 12 10:07:10 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 -->
… …
35<li><a href="#code_ev_idle_code_when_you_ve_got_no"><code>ev_idle</code> - when you've got nothing better to do</a></li> 35<li><a href="#code_ev_idle_code_when_you_ve_got_no"><code>ev_idle</code> - when you've got nothing better to do</a></li>
36<li><a href="#code_ev_prepare_code_and_code_ev_che"><code>ev_prepare</code> and <code>ev_check</code> - customise your event loop</a></li> 36<li><a href="#code_ev_prepare_code_and_code_ev_che"><code>ev_prepare</code> and <code>ev_check</code> - customise your event loop</a></li>
37</ul> 37</ul>
38</li> 38</li>
39<li><a href="#OTHER_FUNCTIONS">OTHER FUNCTIONS</a></li> 39<li><a href="#OTHER_FUNCTIONS">OTHER FUNCTIONS</a></li>
40<li><a href="#LIBEVENT_EMULATION">LIBEVENT EMULATION</a></li>
41<li><a href="#C_SUPPORT">C++ SUPPORT</a></li>
40<li><a href="#AUTHOR">AUTHOR</a> 42<li><a href="#AUTHOR">AUTHOR</a>
41</li> 43</li>
42</ul><hr /> 44</ul><hr />
43<!-- INDEX END --> 45<!-- INDEX END -->
44 46
… …
586 <p>It must return the next time to trigger, based on the passed time value 588 <p>It must return the next time to trigger, based on the passed time value
587(that is, the lowest time value larger than to the second argument). It 589(that is, the lowest time value larger than to the second argument). It
588will usually be called just before the callback will be triggered, but 590will usually be called just before the callback will be triggered, but
589might be called at other times, too.</p> 591might be called at other times, too.</p>
590 <p>NOTE: <i>This callback must always return a time that is later than the 592 <p>NOTE: <i>This callback must always return a time that is later than the
591passed <code>now</code> value</i>. Not even <code>now</code> itself will do, it must be larger.</p> 593passed <code>now</code> value</i>. Not even <code>now</code> itself will do, it <i>must</i> be larger.</p>
592 <p>This can be used to create very complex timers, such as a timer that 594 <p>This can be used to create very complex timers, such as a timer that
593triggers on each midnight, local time. To do this, you would calculate the 595triggers on each midnight, local time. To do this, you would calculate the
594next midnight after <code>now</code> and return the timestamp value for this. How you do this 596next midnight after <code>now</code> and return the timestamp value for this. How
595is, again, up to you (but it is not trivial).</p> 597you do this is, again, up to you (but it is not trivial, which is the main
598reason I omitted it as an example).</p>
596 </dd> 599 </dd>
597 </dl> 600 </dl>
598 </p> 601 </p>
599 </dd> 602 </dd>
600 <dt>ev_periodic_again (loop, ev_periodic *)</dt> 603 <dt>ev_periodic_again (loop, ev_periodic *)</dt>
… …
673 676
674</div> 677</div>
675<h2 id="code_ev_prepare_code_and_code_ev_che"><code>ev_prepare</code> and <code>ev_check</code> - customise your event loop</h2> 678<h2 id="code_ev_prepare_code_and_code_ev_che"><code>ev_prepare</code> and <code>ev_check</code> - customise your event loop</h2>
676<div id="code_ev_prepare_code_and_code_ev_che-2"> 679<div id="code_ev_prepare_code_and_code_ev_che-2">
677<p>Prepare and check watchers are usually (but not always) used in tandem: 680<p>Prepare and check watchers are usually (but not always) used in tandem:
678Prepare watchers get invoked before the process blocks and check watchers 681prepare watchers get invoked before the process blocks and check watchers
679afterwards.</p> 682afterwards.</p>
680<p>Their main purpose is to integrate other event mechanisms into libev. This 683<p>Their main purpose is to integrate other event mechanisms into libev. This
681could be used, for example, to track variable changes, implement your own 684could be used, for example, to track variable changes, implement your own
682watchers, integrate net-snmp or a coroutine library and lots more.</p> 685watchers, integrate net-snmp or a coroutine library and lots more.</p>
683<p>This is done by examining in each prepare call which file descriptors need 686<p>This is done by examining in each prepare call which file descriptors need
684to be watched by the other library, registering <code>ev_io</code> watchers for 687to be watched by the other library, registering <code>ev_io</code> watchers for
685them and starting an <code>ev_timer</code> watcher for any timeouts (many libraries 688them and starting an <code>ev_timer</code> watcher for any timeouts (many libraries
686provide just this functionality). Then, in the check watcher you check for 689provide just this functionality). Then, in the check watcher you check for
687any events that occured (by checking the pending status of all watchers 690any events that occured (by checking the pending status of all watchers
688and stopping them) and call back into the library. The I/O and timer 691and stopping them) and call back into the library. The I/O and timer
689callbacks will never actually be called (but must be valid neverthelles, 692callbacks will never actually be called (but must be valid nevertheless,
690because you never know, you know?).</p> 693because you never know, you know?).</p>
691<p>As another example, the Perl Coro module uses these hooks to integrate 694<p>As another example, the Perl Coro module uses these hooks to integrate
692coroutines into libev programs, by yielding to other active coroutines 695coroutines into libev programs, by yielding to other active coroutines
693during each prepare and only letting the process block if no coroutines 696during each prepare and only letting the process block if no coroutines
694are ready to run (its actually more complicated, it only runs coroutines 697are ready to run (it's actually more complicated: it only runs coroutines
695with priority higher than the event loop and one lower priority once, 698with priority higher than or equal to the event loop and one coroutine
696using idle watchers to keep the event loop from blocking if lower-priority 699of lower priority, but only once, using idle watchers to keep the event
697coroutines exist, thus mapping low-priority coroutines to idle/background 700loop from blocking if lower-priority coroutines are active, thus mapping
698tasks).</p> 701low-priority coroutines to idle/background tasks).</p>
699<dl> 702<dl>
700 <dt>ev_prepare_init (ev_prepare *, callback)</dt> 703 <dt>ev_prepare_init (ev_prepare *, callback)</dt>
701 <dt>ev_check_init (ev_check *, callback)</dt> 704 <dt>ev_check_init (ev_check *, callback)</dt>
702 <dd> 705 <dd>
703 <p>Initialises and configures the prepare or check watcher - they have no 706 <p>Initialises and configures the prepare or check watcher - they have no
… …
724 <p>If <code>timeout</code> is less than 0, then no timeout watcher will be 727 <p>If <code>timeout</code> is less than 0, then no timeout watcher will be
725started. Otherwise an <code>ev_timer</code> watcher with after = <code>timeout</code> (and 728started. Otherwise an <code>ev_timer</code> watcher with after = <code>timeout</code> (and
726repeat = 0) will be started. While <code>0</code> is a valid timeout, it is of 729repeat = 0) will be started. While <code>0</code> is a valid timeout, it is of
727dubious value.</p> 730dubious value.</p>
728 <p>The callback has the type <code>void (*cb)(int revents, void *arg)</code> and gets 731 <p>The callback has the type <code>void (*cb)(int revents, void *arg)</code> and gets
729passed an events set like normal event callbacks (with a combination of 732passed an <code>revents</code> set like normal event callbacks (a combination of
730<code>EV_ERROR</code>, <code>EV_READ</code>, <code>EV_WRITE</code> or <code>EV_TIMEOUT</code>) and the <code>arg</code> 733<code>EV_ERROR</code>, <code>EV_READ</code>, <code>EV_WRITE</code> or <code>EV_TIMEOUT</code>) and the <code>arg</code>
731value passed to <code>ev_once</code>:</p> 734value passed to <code>ev_once</code>:</p>
732<pre> static void stdin_ready (int revents, void *arg) 735<pre> static void stdin_ready (int revents, void *arg)
733 { 736 {
734 if (revents &amp; EV_TIMEOUT) 737 if (revents &amp; EV_TIMEOUT)
… …
757 <p>Feed an event as if the given signal occured (loop must be the default loop!).</p> 760 <p>Feed an event as if the given signal occured (loop must be the default loop!).</p>
758 </dd> 761 </dd>
759</dl> 762</dl>
760 763
761</div> 764</div>
765<h1 id="LIBEVENT_EMULATION">LIBEVENT EMULATION</h1><p><a href="#TOP" class="toplink">Top</a></p>
766<div id="LIBEVENT_EMULATION_CONTENT">
767<p>TBD.</p>
768
769</div>
770<h1 id="C_SUPPORT">C++ SUPPORT</h1><p><a href="#TOP" class="toplink">Top</a></p>
771<div id="C_SUPPORT_CONTENT">
772<p>TBD.</p>
773
774</div>
762<h1 id="AUTHOR">AUTHOR</h1><p><a href="#TOP" class="toplink">Top</a></p> 775<h1 id="AUTHOR">AUTHOR</h1><p><a href="#TOP" class="toplink">Top</a></p>
763<div id="AUTHOR_CONTENT"> 776<div id="AUTHOR_CONTENT">
764<p>Marc Lehmann &lt;libev@schmorp.de&gt;.</p> 777<p>Marc Lehmann &lt;libev@schmorp.de&gt;.</p>
765 778
766</div> 779</div>

Diff Legend

– Removed lines
+ Added lines
< Changed lines
> Changed lines