有用的代码小片段1–主机名->IP

  struct hostent *host;
  struct sockaddr_in serv_addr;
  host = gethostbyname(argv[1]));
  serv_addr.sin_family = AF_INET;
  serv_addr.sin_port = htons(9999);
  serv_addr.sin_addr = *((struct in_addr *)host->h_addr);
  bzero(&(serv_addr.sin_zero),8);