関数自体が持つパラメータの数を取得する方法

<?php <br /><br />function hello($param1,$param2,...){<br />	echo 'function name is:'. __FUNCTION__; // get function itself name<br />	// how to get how many parameters in these function ,<br />	echo '<br>has ? parameters';<br />}<br />hello();

<br />function hello(){<br />    echo 'function name is:'. __FUNCTION__; // get function itself name<br />    // how to get how many parameters in these function ,<br />    echo '<br>has '.func_num_args().' parameters<br>';<br />    $params = func_get_args();<br />    foreach($params as $param){<br />        echo $param.'<br>';<br />    }<br />}<br />hello(1,2,3);<br />