How can the PHP session settings impact the functionality of session variables in a script?

PHP session settings can impact the functionality of session variables in a script by affecting the lifespan, security, and behavior of the session. To ensure proper functionality, it is important to set session settings such as session.cookie_lifetime, session.gc_maxlifetime, session.cookie_secure, and session.cookie_httponly appropriately based on the requirements of the application.

// Set session settings
ini_set('session.cookie_lifetime', 3600); // Set cookie lifetime to 1 hour
ini_set('session.gc_maxlifetime', 3600); // Set session garbage collection lifetime to 1 hour
ini_set('session.cookie_secure', 1); // Enable secure cookies
ini_set('session.cookie_httponly', 1); // Enable HTTP only cookies

// Start the session
session_start();

// Access session variables
$_SESSION['user_id'] = 123;