úÎ Œ Y      -The Enum instance may not be very efficient, &but it should hardly be used, at all. Better use constants such as  and set manipulation. ;If the binary logarithm is computed by constant unfolding, Jperformance would be better, but direct set manipulation is still faster. We implement the  instance in this way, Cin order to stay independent from the particular Poll definitions, #that may differ between platforms.          poll-0.0System.Posix.PollFdfdeventsrEventsEventsEventNValHupErrOutPriInOtherinppriouterrhupnVal eventFlagSet $fEnumEventbaseGHC.EnumEnum