static int is_network_up (int sock)
CLIENT * clntudp_create (raddr, program, version, wait, sockp) struct sockaddr_in *raddr; u_long program; u_long version; struct timeval wait; int *sockp;
INTDEF (clntudp_create)static intis_network_up (int sock){  struct ifaddrs *ifa;  if (getifaddrs (&ifa) != 0)    return 0;  struct ifaddrs *run = ifa;  while (run != NULL)    {      if ((run->ifa_flags & IFF_UP) != 0	  && run->ifa_addr != NULL	  && run->ifa_addr->sa_family == AF_INET)	break;      run = run->ifa_next;    }  freeifaddrs (ifa);  return run != NULL;}