How to get the hostname of an ip address by using asio library?

问题

I am trying to get hostname from UDP endpoint. However I do not know whether boost.asio supports IP->hostname conversion. Anyone can answer my question?

回答1:

getnameinfo is what you want.

getnameinfo((sockaddr*)&addr, sizeof(addr), hostname, sizeof(hostname), NULL, NULL, 0);

回答2:

#include<asio.hpp>
#include<exception>
#include<iostream>

int main()
{
try
{
    asio::io_service io_service;
    asio::ip::udp::resolver rsv(io_service);
    for(const auto &ele : rsv.resolve(asio::ip::udp::endpoint(asio::ip::address_v4({192,168,1,163}),0)))
    {
        std::cout<<ele.host_name()<<'\n';
    }

}
catch(const std::exception &e)
{
    std::cerr<<e.what()<<'\n';
    return 1;
}
}

I have found out how to get host name by ip. Just directly resolve endpoint by using ip address

来源：https://stackoverflow.com/questions/49303769/how-to-get-the-hostname-of-an-ip-address-by-using-asio-library