# Execute prepared statement named `stmt_name` with `values`
  #
  # * `num_params` specifies the number of parameters given to the prepared statement
  # * `param_lengths` specifies the length of each parameters
  # * `param_formats` and `result_format` specifies the format used as input/output.
  #   Should be 0 for text results, 1 for binary.
  #
  # See `prepare`.
  fun exec_prepared(stmt_name: String, num_params: Int, values: Array[String], param_lengths: Array[Int], param_formats: Array[Int], result_format: Int):PGResult do
    return new PGResult(native_connection.exec_prepared(stmt_name, num_params, values, param_lengths, param_formats, result_format))
  end