What are the best practices for including external PHP files, such as a phpBB forum, in a PHP project?

When including external PHP files, such as a phpBB forum, in a PHP project, it is important to use the include or require functions to ensure that the code from the external file is properly integrated into your project. This helps maintain code organization and reusability. Additionally, make sure to check for any dependencies or conflicts with existing code in your project to avoid any issues.

// Include the external PHP file (e.g. phpBB forum)
require_once 'path/to/external/file.php';