// php 4.x 반올림 에러 문제 해결

function mround($number, $precision=0) {
    $precision = ($precision == 0 ? 1 : $precision);
    $pow = pow(10, $precision);
    $ceil = ceil($number * $pow)/$pow;
    $floor = floor($number * $pow)/$pow;
    $pow = pow(10, $precision+1);
    $diffCeil = $pow*($ceil-$number);
    $diffFloor = $pow*($number-$floor)+($number < 0 ? -1 : 1);

    if($diffCeil >= $diffFloor) return $floor;
    else return $ceil;
}

echo mround(4.015,2); // 4.02