c++ - boost ASIO 服务器段错误

Question

我使用 Boost ASIO 创建了一个服务器。它构建良好，但一旦我运行它，它就会出现段错误。无法真正弄清楚这种行为。

另外，我读到这可能是因为我没有明确初始化 io_service 对象。如果是这种情况，那么我该如何修改这段代码，这样我就不必从类外部传递 io_service 对象。

下面是我的代码:

#include <iostream>
#include <string>
#include <memory>
#include <array>
#include <boost/asio.hpp>

using namespace boost::asio;

//Connection Class

class Connection : public std::enable_shared_from_this<Connection>{

    ip::tcp::socket m_socket;
    std::array<char, 2056> m_acceptMessage;
    std::string m_acceptMessageWrapper;
    std::string m_buffer;
public:
    Connection(io_service& ioService): m_socket(ioService) {    }

    virtual ~Connection() { }

    static std::shared_ptr<Connection> create(io_service& ioService){
        return std::shared_ptr<Connection>(new Connection(ioService));
    }


    std::string& receiveMessage() {
         size_t len = boost::asio::read(m_socket, boost::asio::buffer(m_acceptMessage));
         m_acceptMessageWrapper = std::string(m_acceptMessage.begin(), m_acceptMessage.begin() + len);
         return m_acceptMessageWrapper;
    }

    void sendMessage(const std::string& message) {
         boost::asio::write(m_socket, boost::asio::buffer(message));
    }

    ip::tcp::socket& getSocket(){
        return m_socket;
    }

};



//Server Class

class Server {
  ip::tcp::acceptor m_acceptor;
  io_service m_ioService ;


public:
    Server(int port):
        m_acceptor(m_ioService, ip::tcp::endpoint(ip::tcp::v4(), port)){    }

    virtual ~Server() { }

    std::shared_ptr<Connection> createConnection(){
        std::shared_ptr<Connection> newConnection = Connection::create(m_ioService);
        m_acceptor.accept(newConnection->getSocket());
        return newConnection;
    }

    void runService() {
        m_ioService.run();
    }


};


int main(int argc, char* argv[]) {
    Server s(5000);
    auto c1 = s.createConnection();
    //do soething
    s.runService();
    return 0;
}

Answer 1

您面临初始化顺序问题。在您的类 Server 中，您在 m_ioService 之前声明了 m_acceptor 并使用未初始化的 io_service 对象来构造 接受者。

只需重新排列类内的声明即可。令人惊讶的是 clang 并没有为此给出任何警告。

class Server {
  io_service m_ioService ;
  ip::tcp::acceptor m_acceptor;


public:
    Server(int port):
        m_acceptor(m_ioService, ip::tcp::endpoint(ip::tcp::v4(), port)){    }

    virtual ~Server() { }

    std::shared_ptr<Connection> createConnection(){
        std::shared_ptr<Connection> newConnection = Connection::create(m_ioService);
        m_acceptor.accept(newConnection->getSocket());
        return newConnection;
    }

    void runService() {
        m_ioService.run();
    }


};