Question

我有以下课程：

typedef std::pair<boost::asio::ip::tcp::socket, boost::asio::ip::tcp::socket>  socket_pair;

class ConnectionPair {
private:
    socket_pair _sockPair;
public:
    ConnectionPair(boost::asio::io_service &ios);
}

如何在构造函数中初始化对中的套接字？以下内容无法编译：

ConnectionPair::ConnectionPair(asio::io_service &ios):
    _ios(ios),  
    _sockPair(asio::ip::tcp::socket(ios), asio::ip::tcp::socket(ios)){
}

编辑：这是编译器错误。享受：

/boost_1_47_0/boost/asio/basic_io_object.hpp: In copy constructor ‘boost::asio::basic_socket<boost::asio::ip::tcp, boost::asio::stream_socket_service<boost::asio::ip::tcp> >::basic_socket(const boost::asio::basic_socket<boost::asio::ip::tcp, boost::asio::stream_socket_service<boost::asio::ip::tcp> >&)’:

/boost_1_47_0/boost/asio/basic_socket.hpp:43:1:   instantiated from ‘std::pair<_T1, _T2>::pair(const _T1&, const _T2&) [with _T1 = boost::asio::basic_stream_socket<boost::asio::ip::tcp>, _T2 = boost::asio::basic_stream_socket<boost::asio::ip::tcp>]’
/devel/msm1/connection.cpp:8:67:   instantiated from here
/boost_1_47_0/boost/asio/basic_io_object.hpp:163:3: error: ‘boost::asio::basic_io_object<IoObjectService>::basic_io_object(const boost::asio::basic_io_object<IoObjectService>&) [with IoObjectService = boost::asio::stream_socket_service<boost::asio::ip::tcp>, boost::asio::basic_io_object<IoObjectService> = boost::asio::basic_io_object<boost::asio::stream_socket_service<boost::asio::ip::tcp> >]’ is private
/boost_1_47_0/boost/asio/basic_socket.hpp:43:1: error: within this context
In file included from /boost_1_47_0/boost/asio.hpp:30:0,

Answer 1

如果类型是可复制构造的，那么您的代码就可以工作了。我猜（并且只是猜测，因为你没有指定编译器错误）套接字不是可复制构造的。由于std :: pair不允许就地工厂，你必须使你的对成为一对boost :: optional并使用就地工厂。有关详细信息，请参阅the boost documentation。

Answer 2

boost::asio::ip::tcp::socket是否支持复制？我不指望它。 std::pair中的类型必须是可复制的。

Answer 3

您可以像尝试一样初始化该对，但您的代码中还有其他一些错误。

课程声明结尾没有半冒号。
_ios成员变量不存在。

不幸的是我没有安装boost，但这使用G ++ 4.1.2编译我的

#include <utility>

typedef std::pair<int, int> socket_pair;

class ConnectionPair
{
private:
        socket_pair _sockPair;

public:
        ConnectionPair(const int x);
};

ConnectionPair::ConnectionPair(const int x):
        _sockPair(x, x)
{
}

int main(int argc, const char *argv[])
{
        ConnectionPair c(10);
}

c ++：如何在构造函数中初始化std :: pair的成员

3 个答案: