Description:
------------
mysqli does not handle 4-byte floats correctly. It casts it into a double which essentially increases the "error" in the IEEE-754 FP number.

Consider the following C code:
float a = 99.99f;
double b = (double) a;

The output will be:
a = 99.9899979
b = 99.989997863769531

b will never be printed as 99.99

Test script:
---------------
On a MySQL DB, run the following queries:

CREATE TABLE test(id INT PRIMARY KEY, fp4 FLOAT, fp8 DOUBLE) ENGINE = InnoDB;
INSERT INTO test(id, fp4, fp8) VALUES (1, 9.9999, 9.9999)

Now using mysqli, SELECT the one row out:
        if (!($stmt = mysqli_prepare($link, "SELECT id, fp4, fp8 FROM test"))) {
                die();
        }
        if (!mysqli_stmt_execute($stmt)) {
                die();
        }
        if (!($result = mysqli_stmt_get_result($stmt))) {
                die();
        }
        $data = mysqli_fetch_assoc($result);
        print $data['id'] . ": " . $data['fp4'] . ": " . $data['fp8'] . "\n";

Expected result:
----------------
It should be:
1: 9.9999: 9.9999

Actual result:
--------------
The output will be:
1: 9.9998998641968: 9.9999