How does the use of session_id() function in PHP compare to directly accessing session variables?

When using the session_id() function in PHP, you can retrieve or set the current session ID without directly accessing the session variables. This can be useful when you need to manipulate the session ID separately from the session data. Here is an example of how to use session_id() function in PHP:

// Start the session
session_start();

// Get the current session ID
$session_id = session_id();

// Set a new session ID
$new_session_id = 'new_session_id';
session_id($new_session_id);

// Start the session with the new session ID
session_start();