<?php

$doubles = array(
    290000000000000000,
    290000000000000,
    29000000000000,
    29000000000000.123123,
    29000000000000.7123123,
    29000.7123123,
    239234242.7123123,
    0.12345678901234567890,
    10000000000000,
    100000000000000,
    1000000000000000001,
    100000000000001,
    10000000000,
    999999999999999,
    9999999999999999,
    (float)0
    );

foreach ($doubles as $d) {
    var_dump((string)$d);
}

echo "Done\n";
?>