Using getaddrinfo not giving desired output

extern "C"
int RTinet_lookup( const char * host, char * address, unsigned int port)  
{
  struct addrinfo hints, *res;
  int errcode;
  char addrstr[INET6_ADDRSTRLEN];
  void *ptr;

  memset (&hints, 0, sizeof (hints));
  hints.ai_family = AF_UNSPEC;
  hints.ai_socktype = SOCK_STREAM;
  hints.ai_protocol = IPPROTO_TCP;
  hints.ai_flags |= AI_CANONNAME;

  errcode = getaddrinfo (host, "port", &hints, &res);
  /*if (errcode != 0)
    {
      perror ("getaddrinfo");
      return -1;
    }*/

  INFO(STR("Host: %s", host));
  while (res)
    {
      inet_ntop (res->ai_family, res->ai_addr->sa_data, addrstr,INET6_ADDRSTRLEN);
      INFO(STR("Inside while condition with res "));
      switch (res->ai_family)
        {
        case AF_INET:
          ptr = &((struct sockaddr_in *) res->ai_addr)->sin_addr;
          break;
        case AF_INET6:
          ptr = &((struct sockaddr_in6 *) res->ai_addr)->sin6_addr;
          break;
        }
      inet_ntop (res->ai_family, ptr, addrstr,INET6_ADDRSTRLEN);
      INFO(STR("IPv%d address: %s (%s)\n", res->ai_family == AF_INET6 ? 6 : 4,
              addrstr, res->ai_canonname));
      res = res->ai_next;
    }INFO(STR("IPv%d address: %s (%s)\n", res->ai_fa开发者_运维技巧mily == AF_INET6 ? 6 : 4,
              addrstr, res->ai_canonname));
   return 1;
}

In this code, it's not going in while part as res is NULL maybe. Can anyone point out the error here or correct the way getaddrinfo is used?

The one error I see in this code is the "port" parameter being passed to getaddrinfo. this is probably not what was intended, and will most likely fail unless your system does have a service named "port" defined.

Either pass NULL as the service name and override the port in the resultant address, or pass a string containing the name or decimal representation of the port. (in the latter case, you may also want to set the AI_NUMERICSERV flag in the hints).

As a side note, your code isn't calling freeaddrinfo, so is leaking memory.