- filter_var: documentation ( source)
- var_export: documentation ( source)
<?php
var_export(filter_var(' 0100 ', FILTER_VALIDATE_INT));
echo "\n";
var_export(filter_var('0100', FILTER_VALIDATE_INT));
echo "\n";
var_export(filter_var(' +0 ', FILTER_VALIDATE_INT));
echo "\n";