if (isset($_SESSION['loggedin']) && $_SESSION['loggedin'] == true) { echo "Welcome back, " . $_SESSION['username'] . "!"; } else { echo "Please log in to continue."; }
function is_logged_in() { return (isset($_SESSION['loggedin']) && $_SESSION['loggedin'] == true); }This code defines a `is_logged_in` function that returns true if the `loggedin` session variable is set to true and false otherwise. Package Library: This function does not require any external package libraries as it is a built-in feature of PHP.