enum ATL_URL_SCHEME{
   ATL_URL_SCHEME_UNKNOWN = -1,
   ATL_URL_SCHEME_FTP     = 0,
   ATL_URL_SCHEME_GOPHER  = 1,
   ATL_URL_SCHEME_HTTP    = 2,
   ATL_URL_SCHEME_HTTPS   = 3,
   ATL_URL_SCHEME_FILE    = 4,
   ATL_URL_SCHEME_NEWS    = 5,
   ATL_URL_SCHEME_MAILTO  = 6,
   ATL_URL_SCHEME_SOCKS   = 7
};