<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="content-type" content="text/html; charset=UTF-8"> <title>Watchers</title> </head> <body><div class="manualnavbar" style="text-align: center;"> <div class="prev" style="text-align: left; float: left;"><a href="ev.examples.html">Examples</a></div> <div class="next" style="text-align: right; float: right;"><a href="ev.watcher-callbacks.html">Watcher callbacks</a></div> <div class="up"><a href="book.ev.html">Ev</a></div> <div class="home"><a href="index.html">PHP Manual</a></div> </div><hr /><div id="ev.watchers" class="chapter"> <h1>Watchers</h1> <p class="para"> A watcher is an object that gets created to record interest in some event. For instance, the following code waits for <strong><code>STDIN</code></strong> to become readable: <div class="example-contents"> <div class="phpcode"><code><span style="color: #000000"> <span style="color: #0000BB"><?php<br /></span><span style="color: #FF8000">// Wait until STDIN is readable<br /></span><span style="color: #0000BB">$w </span><span style="color: #007700">= new </span><span style="color: #0000BB">EvIo</span><span style="color: #007700">(</span><span style="color: #0000BB">STDIN</span><span style="color: #007700">, </span><span style="color: #0000BB">Ev</span><span style="color: #007700">::</span><span style="color: #0000BB">READ</span><span style="color: #007700">, function (</span><span style="color: #0000BB">$watcher</span><span style="color: #007700">, </span><span style="color: #0000BB">$revents</span><span style="color: #007700">) {<br /> echo </span><span style="color: #DD0000">"STDIN is readable\n"</span><span style="color: #007700">;<br />});<br /></span><span style="color: #0000BB">Ev</span><span style="color: #007700">::</span><span style="color: #0000BB">run</span><span style="color: #007700">(</span><span style="color: #0000BB">Ev</span><span style="color: #007700">::</span><span style="color: #0000BB">RUN_ONCE</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">?></span> </span> </code></div> </div> </p> <p class="para"> All the watcher constructors automatically start the watchers. <em>createStopped</em> methods create stopped watchers(e.g. <span class="methodname"><a href="evio.createstopped.html" class="methodname">EvIo::createStopped()</a></span> ) </p> <p class="para"> Note that a watcher will automatically be stopped when the watcher object is destroyed. Therefore, the watcher objects returned by the constructors or factory methods should be kept. </p> <p class="para"> Note also that all methods changing some watcher property( <em class="emphasis">set</em> , <var class="varname"><var class="varname">priority</var></var> etc.) automatically stop and start it again if it is active, which means pending events get lost. </p> <p class="para"> See also: <a href="ev.watcher-callbacks.html" class="link">Watcher callbacks</a> . </p> </div> <hr /><div class="manualnavbar" style="text-align: center;"> <div class="prev" style="text-align: left; float: left;"><a href="ev.examples.html">Examples</a></div> <div class="next" style="text-align: right; float: right;"><a href="ev.watcher-callbacks.html">Watcher callbacks</a></div> <div class="up"><a href="book.ev.html">Ev</a></div> <div class="home"><a href="index.html">PHP Manual</a></div> </div></body></html>