- var_dump: documentation ( source)
- version_compare: documentation ( source)
- define: documentation ( source)
<?php
define('DEFINED_LOWER', '1.3.0.0');
define('DEFINED_HIGHER', '1.6.0.0');
$version = 1.4;
var_dump ( version_compare(DEFINED_HIGHER, $version, '<'));
var_dump ( version_compare(NOT_DEFINED, $version, '<'));
var_dump ( version_compare(DEFINED_LOWER, $version, '<'));
var_dump ( version_compare(NOT_DEFINED, $version, '<'));