NAME
        CheckDate -- checks a clockdata structure for legal date. (v36)

   SYNOPSIS
        seconds = CheckDate(date);
        D0                  A0

        ULONG CheckDate(struct clockdata *);

   FUNCTION
        Determines if the clockdata structure contains legal date information
        and returns the number of seconds from 01-Jan-1978 to that date, or 0
        if the clockdata structure contains illegal data.

   INPUTS
        date - a filled-in clockdata structure

   RESULTS
        seconds - 0 if date is invalid, otherwise the number of seconds from
                  01-Jan-1978 to the date

   BUGS
        The wday field of the clockdata structure is not checked.

   SEE ALSO
        amiga2date(), date2amiga()