get

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  1.     ///
  2.     /// \brief get
  3.     ///     get value by key from the cluster.
  4.     /// \param hashkey
  5.     /// used to decide which partition to get this k-v
  6.     /// \param sortkey
  7.     /// all the k-v under hashkey will be sorted by sortkey.
  8.     /// \param value
  9.     /// the returned value will be put into it.
  10.     /// \param timeout_milliseconds
  11.     /// if wait longer than this value, will return time out error
  12.     /// \return
  13.     /// int, the error indicates whether or not the operation is succeeded.
  14.     /// this error can be converted to a string using get_error_string().
  15.     /// returns PERR_NOT_FOUND if no value is found under the <hashkey,sortkey>.
  16.     ///
  17.     virtual int get(const std::string &hashkey,
  18.                     const std::string &sortkey,
  19.                     std::string &value,
  20.                     int timeout_milliseconds = 5000,
  21.                     internal_info *info = NULL) = 0;