使用带 ref 参数的成员函数创建线程时出现编译错误

Question

我正在尝试做一个 std::tread 所以我已经看了一些教程但是当我做同样的事情时（我认为）它没有编译。

这是我的Network_class，"receiveFromServer"成员函数应该是线程函数。

class Network_ {
public:
    bool errorInfo(sf::Socket::Status status) {
        switch (status)
        {
        case sf::Socket::Done:
            return true;
            break;
        case sf::Socket::NotReady:
            std::cout << "The socket is not ready to send / receive data yet." << std::endl;
            return false;
            break;
        case sf::Socket::Partial:
            std::cout << "The socket sent a part of the data." << std::endl;
            return false;
            break;
        case sf::Socket::Disconnected:
            std::cout << "The socket has been disconnected." << std::endl;
            return false;
            break;
        case sf::Socket::Error:
            std::cout << "An unexpected error happened." << std::endl;
            return false;
            break;
        default:
            return false;
            break;
        }
    }

    void receiveFromServer(sf::RenderWindow &RW) {
        sf::Packet packet;
        std::string string;

        while (RW.isOpen())
            if (_selector.wait() && _selector.isReady(_socket)) {
                if (errorInfo(_socket.receive(packet))) {
                    packet >> string;
                    packet.clear();
                    std::cout << string << std::endl;
                }
            }
            else
                RW.close();
    }

private:
    sf::SocketSelector _selector;
    sf::TcpSocket _socket;

这是我主要内容的一部分

Network_ network;

if (network.connectToServer(ip, port)) {
    Window_ window;
    sf::RenderWindow *RW = window.create_window("test", 10);
    std::thread receiveThread(&Network_::receiveFromServer, &network, std::ref(RW));

    return gameLoop(*RW);
}

我得到了这个错误 static assertion failed: std::thread arguments must be invocable after conversion to rvalues，下面有很多废话。

有人可以帮我吗？谢谢:)

Answer 1

您的 receiveFromServer 函数需要对 sf::RenderWindow 的引用，但您传递的是 sf::RenderWindow*&。

这里有几种解决方案。

按值传递，因为它只是一个指针

void receiveFromServer(sf::RenderWindow* RW) // sf::RenderWindow* instead of sf::RenderWidnow&
{ /* ... */}

std::thread receiveThread(&Network_::receiveFromServer, &network, RW); // pass by value

按引用传递 - 没用

void receiveFromServer(sf::RenderWindow*& RW) // sf::RenderWindow*& instead of sf::RenderWidnow&
{ /* ... */}

std::thread receiveThread(&Network_::receiveFromServer, &network, std::ref(RW)); // pass by reference

通过引用传递而不改变你的函数

void receiveFromServer(sf::RenderWindow& RW) // no change
{ /* ... */}

std::thread receiveThread(&Network_::receiveFromServer, &network, std::ref(*RW)); // dereference and pass by reference

使用带 ref 参数的成员函数创建线程时出现编译错误

compilation error when creating a thread with a member function with ref argument

c++

multithreading

sfml