php-doc-en/reference/weakref/weakref.xml

<?xml version="1.0" encoding="utf-8"?>
<!-- $Revision$ -->
<phpdoc:classref xmlns:phpdoc="http://php.net/ns/phpdoc" xml:id="class.weakref" xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xi="http://www.w3.org/2001/XInclude">
 <title>The WeakRef class</title>
 <titleabbrev>WeakRef</titleabbrev>

 <partintro>

<!-- {{{ weakref intro -->
  <section xml:id="weakref.intro">
   &reftitle.intro;
   <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.
   </para>
  </section>
<!-- }}} -->

  <section xml:id="weakref.synopsis">
   &reftitle.classsynopsis;

<!-- {{{ Synopsis -->
   <classsynopsis>
    <ooclass><classname>WeakRef</classname></ooclass>

<!-- {{{ Class synopsis -->

    <classsynopsisinfo>
     <ooclass>
      <classname>WeakRef</classname>
     </ooclass>

    </classsynopsisinfo>
<!-- }}} -->

    <classsynopsisinfo role="comment">&Methods;</classsynopsisinfo>
    <xi:include xpointer="xmlns(db=http://docbook.org/ns/docbook) xpointer(id('class.weakref')/db:refentry/db:refsect1[@role='description']/descendant::db:constructorsynopsis[1])" />
    <xi:include xpointer="xmlns(db=http://docbook.org/ns/docbook) xpointer(id('class.weakref')/db:refentry/db:refsect1[@role='description']/descendant::db:methodsynopsis[1])" />
   </classsynopsis>

  </section>
<!-- {{{ weakref examples -->
  <section xml:id="weakref.examples">
   &reftitle.examples;
   <para>
    <example>
     <title><classname>WeakRef</classname> usage example</title>
     <programlisting role="php">
<![CDATA[
<?php
class MyClass {
    public function __destruct() {
        echo "Destroying object!\n";
    }
}

$o1 = new MyClass;

$r1 = new WeakRef($o1);

if ($r1->valid()) {
    echo "Object still exists!\n";
    var_dump($r1->get());
} else {
    echo "Object is dead!\n";
}

unset($o1);

if ($r1->valid()) {
    echo "Object still exists!\n";
    var_dump($r1->get());
} else {
    echo "Object is dead!\n";
}
?>
]]>
     </programlisting>
     &example.outputs;
     <screen>
<![CDATA[
Object still exists!
object(MyClass)#1 (0) {
}
Destroying object!
Object is dead!
]]>
     </screen>
    </example>
   </para>
  </section>
<!-- }}} -->

 </partintro>

 &reference.weakref.entities.weakref;

</phpdoc:classref>

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