Why IEEE 754 floating point numbers are a mess to debug

IEEE754.php

<?php
// Live Demo: https://3v4l.org/GWJFZ
// see also: http://0.30000000000000004.com/

var_dump(0.1 + 0.2); // float(0.3)
var_dump(0.3); // float(0.3)
var_dump(0.1 + 0.2 == 0.3); // bool(false) 

// Set the number of significant digits displayed in floating point numbers.
ini_set('precision', 18);

var_dump(0.1 + 0.2); // float(0.300000000000000044)
var_dump(0.3); // float(0.299999999999999989) 
var_dump(0.1 + 0.2 == 0.3); // bool(false)