Description:
------------
When using strval(), implicit conversion or type-casting, floats are converted using locale-aware display formatting, rather than native formatting, as understood by most other software (and PHP itself).

Please understand that this is a complex problem, which requires a lengthy analysis and many examples. I have spent almost 6 hours analyzing this problem in-depth, and created a complete report explaining the problem, suggesting changes, and recommending ways to implement these changes.

Please, don't discard this report without careful consideration - there are fundamental problems with float-handling in PHP, which should be taken seriously.

For the full description and examples, please see this page:

http://public.test.fynskemedier.dk/float/

Thank You.


Reproduce code:
---------------
<?php

setlocale(LC_NUMERIC, 'danish');

function ftos($f) {
    return is_float($f) ? sprintf('%.14F', $f) : 'NaN';
}

$a = 1234.01234567890123456789;

echo "accurate value: " . ftos($a) . "\n\n";
echo "casting float to string: ";
$s = (string) $a;
var_dump($s);
echo "casting back to float: ";
echo ftos( (float) $s ) . "\n\n";

?>

The above is a very simple example, demonstrating one of the issues most commonly encountered by beginning PHP developers.

Please find many more examples and in-depth explanations below:

http://public.test.fynskemedier.dk/float/


Expected result:
----------------
accurate value: 1234.01234567890128

casting float to string: string(19) "1234.01234567890128"
casting back to float: 1234.01234567890128


Actual result:
--------------
accurate value: 1234.01234567890128

casting float to string: string(13) "1234,01234568"
casting back to float: 1234.00000000000000