test_lookup.cpp

#include <iostream>
#include <sys/types.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <stdio.h>

void print_in_addr(struct sockaddr *sa) {
        char buf[100];
        if (sa->sa_family == AF_INET) {
                inet_ntop(AF_INET, &(((struct sockaddr_in*)sa)->sin_addr), buf, sizeof(buf));
                std::cout << "Address (ipv4): " << buf << std::endl;
                return;
        }

        inet_ntop(AF_INET6, &(((struct sockaddr_in6*)sa)->sin6_addr), buf, sizeof(buf));
        std::cout << "Address (ipv6): " << buf << std::endl;
}


int main(int argc, char* argv[])
{
        if(argc!=2) {
                std::cout << "Not enough arguments" << std::endl;
                return 1;
        }

        struct addrinfo hints = {};
        hints.ai_family = AF_UNSPEC;
        hints.ai_socktype = SOCK_STREAM;

        int rv;
        struct addrinfo* servinfo;
        if ((rv = getaddrinfo(argv[1], "55415", &hints, &servinfo)) != 0) {
                perror("getaddrinfo");
                return 1;
        }


        for(struct addrinfo* p = servinfo; p != NULL; p = p->ai_next)
        {
                print_in_addr(p->ai_addr);
        }

        return 0;
}