...
Notes
For the "day of the week" parameter, 1 represents Monday, 2 Tuesday, etc. If you supply zero the routine will work out the day name for you. An invalid date error does not return an error code, just Fc=1.
A date is invalid if inconsistent, eg. you say it is Monday when it should be Tuesday, or if a parameter is out of range.
Related calls
GN_Die, convert internal format date to zoned format
GN_Gdt, convert an ASCII string to an internal binary date
GN_Gmd, Get (read) machine date in internal format
GN_Pdt, write internal date as ASCII string
GN_Pmd, put (set) machine date