#include <stdio.h>
#include <stdlib.h>
#include <netdb.h>
#include <netinet/in.h>
#include <sys/socket.h>

int main(int argc, char *argv[])
{
    struct addrinfo *res, *result;
    int error;

    if(argc < 2)
        return EXIT_FAILURE;

    /* resolve the domain name into a list of addresses */
    error = getaddrinfo(argv[1], NULL, NULL, &result);
    if (error != 0)
    {
        fprintf(stderr, "error in getaddrinfo: %s\n", gai_strerror(error));
        return EXIT_FAILURE;
    }
    else
    {
        printf("Looked up: %s\n", argv[1]);
    }

    /* loop over all returned results and do inverse lookup */
    for (res = result; res != NULL; res = res->ai_next)
    {
        char hostname[NI_MAXHOST] = "";

        error = getnameinfo(res->ai_addr, res->ai_addrlen, hostname, NI_MAXHOST, NULL, 0, NI_NUMERICHOST);
        if (error != 0)
        {
            fprintf(stderr, "error in getnameinfo: %s\n", gai_strerror(error));
            continue;
        }

        if (*hostname != '\0')
            printf("hostname: %s\n", hostname);
    }

    freeaddrinfo(result);
    return EXIT_SUCCESS;
}