如何返回sf::RenderWindow？

#include <SFML/Graphics.hpp>

sf::RenderWindow window(sf::VideoMode(800, 600), "My Window");

while (window.isOpen())
{
    sf::Event event;
    while (window.pollEvent(event))
    {
        if (event.type == sf::Event::Closed)
            window.close();
    }

    window.clear();
    // 在这里进行绘制和更新操作
    window.display();
}

sf::RenderWindow createRenderWindow()
{
    sf::RenderWindow window(sf::VideoMode(800, 600), "My Window");
    return window;
}