woocommerce_checkout_init action-hook . WC 1.0

woocommerce_checkout_init action is ran once when the class is first constructed.

Usage

add_action( 'woocommerce_checkout_init', 'action_function_name_9515' );
function action_function_name_9515( $self::$instance ){
	// action...
}

$self::$instance

-

Where the hook is called

do_action( 'woocommerce_checkout_init', self::$instance );

Where in WP core the hook is used WooCommerce