php - Is there any easy code to convert hex string into ascii? -

i have used 1 code converts hex ascii below:

<?php $convert = ''; function hexstr($hexstr) {   $hexstr = str_replace(' ', '', $hexstr);   $hexstr = str_replace('\x', '', $hexstr);   $retstr = pack('h*', $hexstr);   return $retstr; } $str2 = hexstr($convert); echo($str2); ?> 

it works before shows ascii converted output shows error above like:

( ! ) warning: pack(): type h: illegal hex digit in c:\wamp\www\project\hextostring.php on line 8 

why so? mean showing error , correct output? problem in code? line 8 is:

$retstr = pack('h*', $hexstr);