A ZOOM::connection object represents an open
   connection to a Z39.50 server.  Such a connection is forged by
   constructing a connection object.
  
The class has this declaration:
    class connection {
    public:
      connection (const char *hostname, int portnum);
      ~connection ();
      const char *option (const char *key) const;
      const char *option (const char *key, const char *val);
    };
  
   When a new connection is created, the hostname
   and port number of a Z39.50 server must be supplied, and the
   network connection is forged and wrapped in the new object.  If the
   connection can't be established - perhaps because the hostname
   couldn't be resolved, or there is no server listening on the
   specified port - then an
   exception
   is thrown.
  
   The only other methods on a connection object
   are for getting and setting options.  Any name-value pair of
   strings may be set as options, and subsequently retrieved, but
   certain options have special meanings which are understood by the
   ZOOM code and affect the behaviour of the object that carries
   them.  For example, the value of the
   databaseName option is used as the name of the
   database to query when a search is executed against the
   connection.  For a full list of such special
   options, see the ZOOM abstract API and the ZOOM-C documentation
   (links below).