What are the potential pitfalls of using backslashes as directory separators in PHP include paths?

Using backslashes as directory separators in PHP include paths can lead to compatibility issues when running the code on different operating systems. To avoid this, it is recommended to use the DIRECTORY_SEPARATOR constant provided by PHP, which automatically detects the correct directory separator based on the operating system.

// Incorrect usage of backslashes in include path
include 'path\to\file.php';

// Correct usage of DIRECTORY_SEPARATOR
include 'path' . DIRECTORY_SEPARATOR . 'to' . DIRECTORY_SEPARATOR . 'file.php';