CIGAL Reference Manual, Chapter 4 (day):
usage: dest = day
DAY is a number variable containing the current month and day. This variable is read-only. DAY's value is set at the moment it is read. DAY is set as the month plus the day divided by 100.
On September 12th, DAY = 9.12 On January 1st, DAY = 1.01
At 5:25 pm on October 13th, 1992, the CIGAL command:
ftype '%5/2f/%2d %5:2f:%5.2f\n' day year-1900 hour secs
would print as: