set_user_email() public method

Get user_email.
public set_user_email ( integer $value )
$value integer
/**
 * Grant downloadable product access to the file identified by $download_id.
 *
 * @param  string $download_id file identifier
 * @param  int|WC_Product $product
 * @param  WC_Order $order the order
 * @param  int $qty purchased
 * @return int|bool insert id or false on failure
 */
function wc_downloadable_file_permission($download_id, $product, $order, $qty = 1)
{
    if (is_numeric($product)) {
        $product = wc_get_product($product);
    }
    $download = new WC_Customer_Download();
    $download->set_download_id($download_id);
    $download->set_product_id($product->get_id());
    $download->set_user_id($order->get_customer_id());
    $download->set_order_id($order->get_id());
    $download->set_user_email($order->get_billing_email());
    $download->set_order_key($order->get_order_key());
    $download->set_downloads_remaining(0 > $product->get_download_limit() ? '' : $product->get_download_limit() * $qty);
    $download->set_access_granted(current_time('timestamp'));
    $download->set_download_count(0);
    $expiry = $product->get_download_expiry();
    if ($expiry > 0) {
        $order_completed_date = date_i18n("Y-m-d", $order->get_date_completed());
        $download->set_access_expires(strtotime($order_completed_date . ' + ' . $expiry . ' DAY'));
    }
    return $download->save();
}