weakreference.xml Give more details about the WeakReferences

language/predefined/weakreference.xml

@@ -13,6 +13,13 @@
    <para>
     Weak references allow the programmer to retain a reference to an object which does not prevent
     the object from being destroyed. They are useful for implementing cache like structures.
+    The garbage collector will destroy the original object, and a weak reference will return &null;
+    when calling the <methodname>WeakReference::get</methodname> method,
+    only if there are no variables left that store the
+    <link linkend="language.oop5.references">ID of the original object</link>,
+    more precisely, the object is destroed only when the
+    <link linkend="features.gc.refcounting-basics">refcount</link> for the object is reset to zero;
+    at the same time, creating a weak references do not increase the reference counter.
    </para>
    <para>
     <classname>WeakReference</classname>s cannot be serialized.
@@ -50,11 +57,16 @@
      <programlisting role="php">
 <![CDATA[
 <?php
-$obj = new stdClass;
+
+$obj = new stdClass();
 $weakref = WeakReference::create($obj);
+
 var_dump($weakref->get());
+
 unset($obj);
+
 var_dump($weakref->get());
+
 ?>
 ]]>
      </programlisting>