long coljul (date, format, longyear)
char *date;
int format;
bool longyear;

char *colgre (julian_days, format)
long julian_days;
int format;

char *coldate (date, days, format)
char *date;
int days;
int format;

If the year segment of date is 4 bytes long (yyyy), or if longyear is TRUE, the resulting number of Julian days will reflect the specified (or default current) century for later conversion back to Gregorian.

colgre computes the Gregorian day, month and year from julian_days, and returns a string formatted according to format. format is 0 for computer ([yy]yymmdd); 1 for European (ddmm[yy]yy); and 2 for US (mmdd[yy]yy).

coldate adds days to a Gregorian date in [yy]yymmdd format and returns the resulting pointer to a string, using the format specified by format. format is 0 for computer ([yy]yymmdd); 1 for European (ddmm[yy]yy); and 2 for US (mmdd[yy]yy).