NAME
        DoubleClick -- Test two time values for double-click timing.

    SYNOPSIS
        IsDouble = DoubleClick( StartSecs, StartMicros,
        D0                      D0         D1
                CurrentSecs, CurrentMicros )
                D2           D3

        bool doubleclick( ulong, ulong, ulong, ulong );

    FUNCTION
        Compares the difference in the time values with the double-click
        timeout range that the user has set (using the "Preferences" tool) or
        some other program has configured into the system.  If the
        difference between the specified time values is within the current
        double-click time range, this function returns TRUE, else it
        returns FALSE.

       These time values can be found in input events and IDCMP messages.
       The time values are not perfect; however, they are precise enough for
       nearly all applications.

    INPUTS
        StartSeconds, StartMicros = the timestamp value describing the start of
          the double-click time period you are considering
        CurrentSeconds, CurrentMicros = the timestamp value describing
          the end of the double-click time period you are considering

    RESULT
        If the difference between the supplied timestamp values is within the
        double-click time range in the current set of preferences, this
        function returns TRUE, else it returns FALSE

    BUGS

    SEE ALSO
        currenttime()