1st snippet in post "Save Multiple Option Values in A Single Database Row"

gistfile1.php

<?php

// action for registering setting options
add_action( 'admin_init', 'prfx_register_settings' );

// function for registering prfx setting options
function prfx_register_settings() {
	register_setting( 'prfx-settings-group', 'prfx_options', 'prfx_sanitize_options' );
}