[server]자신의 IP 알아보기

char                    hostname[255];
PHOSTENT                hostinfo = NULL;
    if (gethostname(hostname, sizeof(hostname)) == 0)
        if ((hostinfo = gethostbyname(hostname)) != NULL)
            printf("server address -> %s\n", inet_ntoa(*(struct in_addr*)*hostinfo->h_addr_list));