// Retrieving the value of the "display_errors" configuration option ini_get('display_errors'); // Enabling error reporting for all errors and warnings ini_set('error_reporting', E_ALL); // Retrieving the value of an environment variable getenv('DATABASE_URL');These examples demonstrate the usage of `ini_get`, `ini_set`, and `getenv` functions to retrieve and modify configuration options. These functions are part of the PHP core library and require no additional packages to use.