PHP 计算两个时间相差的天

$d = "2013-03-26 15:30:10";
$d1 = "2013-03-26 18:40:10";

function minDiff($startTime, $endTime) {
    $start =strtotime($startTime);
    $end =strtotime($endTime);
    $timeDiff = $end -$start;

//case "y": $retval = bcdiv($diff,(60 * 60 * 24 * 365)); break;
//case "m": $retval = bcdiv($diff,(60 * 60 * 24 * 30)); break;
//case "w": $retval = bcdiv($diff,(60 * 60 * 24 * 7)); break;
//case "d": $retval = bcdiv($diff,(60 * 60 * 24)); break;
//case "h": $retval = bcdiv($diff,(60 * 60)); break;
//case "n": $retval = bcdiv($diff,60); break;

   //return floor($timeDiff / (60 * 60 *24));//计算天数
    return floor($timeDiff /60);//差幾分鐘
}

echo dateDiff($d,$d1)