Added note about backward compatibility of extending exceptions for PHP < 5.3.0

git-svn-id: https://svn.php.net/repository/phpdoc/en/trunk@301446 c90b9560-bf6c-de11-be94-00142212c4b1

language/exceptions.xml

@@ -173,7 +173,7 @@ class Exception
     </para>
    </note>
    <example>
-    <title>Extending the Exception class</title>
+    <title>Extending the Exception class (PHP V5.3.+)</title>
     <programlisting role="php">
 <![CDATA[
 <?php
@@ -289,6 +289,39 @@ echo "\n\n";
 ?>
 ]]>
     </programlisting>
+    <note>
+     Versions of PHP 5, prior to PHP 5.3.0 do not support nesting of exceptions.
+     The following code fragment can be used as a replacement MyException class
+     if you wish to run this example.
+     <programlisting role="php">
+<![CDATA[
+<?php
+/**
+ * Define a custom exception class
+ */
+class MyException extends Exception
+{
+    // Redefine the exception so message isn't optional
+    public function __construct($message, $code = 0) {
+        // some code
+    
+        // make sure everything is assigned properly
+        parent::__construct($message, $code);
+    }
+
+    // custom string representation of object
+    public function __toString() {
+        return __CLASS__ . ": [{$this->code}]: {$this->message}\n";
+    }
+
+    public function customFunction() {
+        echo "A custom function for this type of exception\n";
+    }
+}
+?>
+]]>
+     </programlisting>
+    </note>
    </example>
   </sect1>