在单独的线程中有多个SFML RenderWindow

Question

在SFML（版本2.1）上遇到一些问题。

尝试在两个独立的线程上创建两个sf :: RenderWindow实例。应用程序工作一段时间（时间量不是恒定的），然后最终会因断言而崩溃：

testapp: ../../src/xcb_conn.c:186: write_vec: Assertion `!c->out.queue_len' failed.

测试代码：

#include <iostream>
#include <thread>

#include <SFML/Window.hpp>
#include <SFML/Graphics.hpp>

#include <X11/Xlib.h>

void WindowOne ()
{
    sf::RenderWindow* wnd = new sf::RenderWindow (sf::VideoMode(800,600),
                                                  "Window 1");

    while (wnd->isOpen())
    {
        sf::Event event;
        while (wnd->pollEvent(event))
        {
            switch (event.type)
            {
            case sf::Event::Closed:
                wnd->close();
                break;
            default:
                break;
            }

        }

        wnd->clear(sf::Color::White);

        wnd->display();

    }
    delete wnd;
}

void WindowTwo ()
{    
    sf::RenderWindow* wnd = new sf::RenderWindow (sf::VideoMode(800,600),
                                                  "Window 2");

    while (wnd->isOpen())
    {
        sf::Event event;
        while (wnd->pollEvent(event))
        {
            switch (event.type)
            {
            case sf::Event::Closed:
                wnd->close();
                break;
            default:
                break;
            }

        }

        wnd->clear(sf::Color::White);

        wnd->display();

    }
    delete wnd;
}

int main(int argc, char** argv) {
    XInitThreads();

    std::thread thread1 (WindowOne);
    std::thread thread2 (WindowTwo);

    thread1.join();
    thread2.join();

    return 0;
}

请帮助我找出，我做错了什么，或者我甚至可以做这些事情。

修改

忘记提到它崩溃了：

wnd->display();