adddouble (TokyoTyrant::RDB)

    # File tokyotyrant.rb, line 572
        def adddouble(key, num)
          key = _argstr(key)
          num = _argnum(num)
          if !@sock
            @ecode = EINVALID
            return nil
          end
          integ = num.truncate
          fract = ((num - integ) * 1000000000000).truncate
          sbuf = [0xC8, 0x61, key.length].pack("CCN")
          sbuf += _packquad(integ) + _packquad(fract) + key
          if !_send(sbuf)
            @ecode = ESEND
            return nil
          end
          code = _recvcode
          if code == -1
            @ecode = ERECV
            return nil
          end
          if code != 0
            @ecode = EKEEP
            return nil
          end
          integ = _recvint64()
          fract = _recvint64()
          return integ + fract / 1000000000000.0
        end