How can one ensure that file paths are referenced correctly regardless of directory depth in PHP?

When referencing file paths in PHP, it's important to use the correct path format to ensure that the file can be located regardless of the directory depth. One way to achieve this is by using the `__DIR__` magic constant to get the absolute path of the current file, and then concatenate it with the relative path to the desired file.

// Example of referencing a file path correctly regardless of directory depth
$file_path = __DIR__ . '/relative/path/to/file.txt';