gistfile1.txt

int get_ip_from_hostname(char *host, char **output, int ip_v6)
{
    int error; 
    struct addrinfo hints, *res;
    struct in_addr addr;

    struct in6_addr addr6;
    
    if(!host || !output)
    {
        printf("bad argument 'host'\n");
        return -1;
    }

    *output = malloc(INET_ADDRSTRLEN);
    if(!*output)
    {
        error = errno;
        printf("malloc error: %s\n", strerror(error));
        return -1;
    }

    memset(&hints, 0, sizeof(struct addrinfo));
    hints.ai_socktype = SOCK_STREAM;
    
    if(ip_v6 != 0)
        hints.ai_family = AF_INET6;
    else
        hints.ai_family = AF_INET;

    hints.ai_flags = 0;

    if((error = getaddrinfo(host, NULL, &hints, &res)) != 0)
    {
        if(error == EAI_NONAME)
            return 1;

        printf("getaddrinfo error: %s", gai_strerror(error));
        return -1;
    }

    if(ip_v6 != 0)
        addr6 = ((struct sockaddr_in *)(res->ai_addr));
    else
        addr.s_addr = ((struct sockaddr_in *)(res->ai_addr))->sin_addr.s_addr;

    if(ip_v6 != 0)
        inet_ntop(AF_INET6, &addr6, *output, INET6_ADDRSTRLEN);
    else
        inet_ntop(AF_INET, &addr, *output, INET_ADDRSTRLEN);

    freeaddrinfo(res);

    return 0;
}