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<title>The WeakRef class</title>
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<h1 class="title">The WeakRef class</h1>
<div class="partintro"><p class="verinfo">(PECL weakref >= 0.1.0)</p>
<div class="section" id="weakref.intro">
<h2 class="title">Introduction</h2>
<p class="para">
The WeakRef class provides a gateway to objects without preventing the garbage collector from freeing those objects.
It also provides a way to turn a weak reference into a strong one.
</p>
</div>
<div class="section" id="weakref.synopsis">
<h2 class="title">Class synopsis</h2>
<div class="classsynopsis">
<div class="ooclass"></div>
<div class="classsynopsisinfo">
<span class="ooclass">
<strong class="classname">WeakRef</strong>
</span>
{</div>
<div class="classsynopsisinfo classsynopsisinfo_comment">/* Methods */</div>
<div class="constructorsynopsis dc-description">
<span class="modifier">public</span> <span class="methodname"><a href="weakref.construct.html" class="methodname">Weakref::__construct</a></span>
([ <span class="methodparam"><span class="type">object</span> <code class="parameter">$object</code></span>
] )</div>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span> <span class="type">bool</span> <span class="methodname"><a href="weakref.acquire.html" class="methodname">Weakref::acquire</a></span>
( <span class="methodparam">void</span>
)</div>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span> <span class="type">object</span> <span class="methodname"><a href="weakref.get.html" class="methodname">Weakref::get</a></span>
( <span class="methodparam">void</span>
)</div>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span> <span class="type">bool</span> <span class="methodname"><a href="weakref.release.html" class="methodname">Weakref::release</a></span>
( <span class="methodparam">void</span>
)</div>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span> <span class="type">bool</span> <span class="methodname"><a href="weakref.valid.html" class="methodname">Weakref::valid</a></span>
( <span class="methodparam">void</span>
)</div>
}</div>
</div>
<div class="section" id="weakref.examples">
<h2 class="title">Examples</h2>
<p class="para">
<div class="example" id="example-548">
<p><strong>Example #1 <strong class="classname">WeakRef</strong> usage example</strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /></span><span style="color: #007700">class </span><span style="color: #0000BB">MyClass </span><span style="color: #007700">{<br /> public function </span><span style="color: #0000BB">__destruct</span><span style="color: #007700">() {<br /> echo </span><span style="color: #DD0000">"Destroying object!\n"</span><span style="color: #007700">;<br /> }<br />}<br /><br /></span><span style="color: #0000BB">$o1 </span><span style="color: #007700">= new </span><span style="color: #0000BB">MyClass</span><span style="color: #007700">;<br /><br /></span><span style="color: #0000BB">$r1 </span><span style="color: #007700">= new </span><span style="color: #0000BB">WeakRef</span><span style="color: #007700">(</span><span style="color: #0000BB">$o1</span><span style="color: #007700">);<br /><br />if (</span><span style="color: #0000BB">$r1</span><span style="color: #007700">-></span><span style="color: #0000BB">valid</span><span style="color: #007700">()) {<br /> echo </span><span style="color: #DD0000">"Object still exists!\n"</span><span style="color: #007700">;<br /> </span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">$r1</span><span style="color: #007700">-></span><span style="color: #0000BB">get</span><span style="color: #007700">());<br />} else {<br /> echo </span><span style="color: #DD0000">"Object is dead!\n"</span><span style="color: #007700">;<br />}<br /><br />unset(</span><span style="color: #0000BB">$o1</span><span style="color: #007700">);<br /><br />if (</span><span style="color: #0000BB">$r1</span><span style="color: #007700">-></span><span style="color: #0000BB">valid</span><span style="color: #007700">()) {<br /> echo </span><span style="color: #DD0000">"Object still exists!\n"</span><span style="color: #007700">;<br /> </span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">$r1</span><span style="color: #007700">-></span><span style="color: #0000BB">get</span><span style="color: #007700">());<br />} else {<br /> echo </span><span style="color: #DD0000">"Object is dead!\n"</span><span style="color: #007700">;<br />}<br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
<div class="example-contents"><p>The above example will output:</p></div>
<div class="example-contents screen">
<div class="cdata"><pre>
Object still exists!
object(MyClass)#1 (0) {
}
Destroying object!
Object is dead!
</pre></div>
</div>
</div>
</p>
</div>
</div>
<h2>Table of Contents</h2><ul class="chunklist chunklist_reference"><li><a href="weakref.acquire.html">Weakref::acquire</a> — Acquires a strong reference on that object</li><li><a href="weakref.construct.html">Weakref::__construct</a> — Constructs a new weak reference</li><li><a href="weakref.get.html">Weakref::get</a> — Returns the object pointed to by the weak reference</li><li><a href="weakref.release.html">Weakref::release</a> — Releases a previously acquired reference</li><li><a href="weakref.valid.html">Weakref::valid</a> — Checks whether the object referenced still exists</li></ul>
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