function checkLogin($username, $password) { // Connect to database $conn = mysqli_connect("localhost", "username", "password", "database"); // Query for user with given username and password $sql = "SELECT * FROM users WHERE username = '$username' AND password = '$password'"; $result = mysqli_query($conn, $sql); // Check if query returned a matching user if (mysqli_num_rows($result) == 1) { return true; // User is authenticated } else { return false; // User is not authorized } }This code connects to a database and checks if there is a user with the specified username and password. If there is a match, the function returns "true" to indicate that the user is authenticated and should be granted access to protected pages. Otherwise, the function returns "false" to indicate that the login credentials are invalid and the user should be redirected to a login page. The package or library used in this example is the MySQLi extension, which provides functions for interacting with MySQL databases using PHP.