How to get a path to the desktop for current user in PHP?
The function getenv() you gives you the value of environment variables set with your web server either your local computer acting as web server or even remote server.
Different development servers store the values of environment variables differently, due to this WAMP is acting differently and XAMPP is differently on your computer.
Try to make call to phpinfo() function, and you will see the complete list of all environment variables available in current installation.
Example 1
<?php
// Show all information, defaults to INFO_ALL
phpinfo();
// Show just the module information.
// phpinfo(8) yields identical results.
phpinfo(INFO_MODULES);
?>Example 2
$var = get_current_user();