bp_get_the_notification_mark_link( int $user_id )

	function bp_get_the_notification_mark_link( $user_id = 0 ) {
		// Set default user ID to use.
		$user_id = 0 === $user_id ? bp_displayed_user_id() : $user_id;

		if ( bp_is_current_action( 'read' ) ) {
			$retval = bp_get_the_notification_mark_unread_link( $user_id );
		} else {
			$retval = bp_get_the_notification_mark_read_link( $user_id );
		}

		/**
		 * Filters the mark link for the current notification.
		 *
		 * @since BuddyPress 1.9.0
		 * @since BuddyPress 2.6.0 Added $user_id as a parameter.
		 *
		 * @param string $retval  The mark link for the current notification.
		 * @param int    $user_id The user ID.
		 */
		return apply_filters( 'bp_get_the_notification_mark_link', $retval, $user_id );
	}