$path = t3lib_div::resolveBackPath('include/header.php', dirname(__FILE__)); include $path;
$path = t3lib_div::resolveBackPath('/var/www/includes/header.php', dirname(__FILE__)); include $path;Here, the first argument to the resolveBackPath function is the absolute path to the file you want to include, and the second argument is the base directory (dirname(__FILE__)). The resolveBackPath function will return the absolute path to the file, which can then be used in the include statement. The t3lib_div library is part of the TYPO3 CMS package.