Getting Error message when using php overload _call
<p>I'm receiving error message  'Fatal error: Call to undefined method CleverString::strlen() in - on line 41' </p>

<p><code>echo "&lt;p&gt;The length of the string is: " . $myString-&gt;strlen() . "&lt;/p&gt;";</code> </p>

<p>I have looked over my code several times but can't point out what is causing the error.</p>

<p>Here is the complete code:</p>

<pre><code>  &lt;?php 

            class CleverString {

                private $_theString = "";
                private static $_allowedFunctions = array( "strlen", "strtoupper", "strpos" );

                public function setString ( $stringVal ){
                    $this-&gt;_theString = $stringVal;
                }

                public function getString(){
                    return $this-&gt;_theString;
                }

                public function _call( $methodName, $arguments ){
                    if ( in_array( $methodName, CleverString::$_allowedFunctions ) ){
                        array_unshift( $arguments, $this-&gt;_theString );
                        return call_user_func_array( $methodName, $arguments );
                    } else {
                        die ( "&lt;p&gt;Method 'CleverString::$methodName' doesn't exist&lt;/p&gt;" );
                    }
                }
            }

            $myString = new CleverString;
            $myString-&gt;setString( "Hello!" );
            echo "&lt;p&gt;The string is: " . $myString-&gt;getString() . "&lt;/p&gt;";
            echo "&lt;p&gt;The length of the string is: " . $myString-&gt;strlen() . "&lt;/p&gt;";
            echo "&lt;p&gt;The string in uppercase letter is: " . $myString-&gt;strtoupper() . "&lt;/p&gt;";
            echo "&lt;p&gt;The letter 'e' occurs at position: " . $myString-&gt;strpos( "e" ) . "&lt;/p&gt;";
            $myString-&gt;madeUpMethod();

                ?&gt;
</code></pre>
