PHP 日期函数 date_offset_get()

<?php
   $dateSrc = '2007-04-19 12:50 GMT';
   $dateTime = date_create( $dateSrc);;
   $retval = date_offset_get( $dateTime);

   echo "Returned value is $retval";
   echo "<br />";

   # Using second function.
   $dateTime = new DateTime($dateSrc);
   $retval = $dateTime->getOffset();

   echo "Returned value is $retval";
?>