Sage X3 end-date of a month

X3 4GL function that returns the end-date of a month

1. Funprog F_ENDOFMONTH(PMONTH,PYEAR)
2. Value Integer PMONTH
3. Value Integer PYEAR
4. Local Date YD
6. PMONTH += 1
7. If PMONTH > 12 Then
8. PMONTH = 1
9. PYEAR += 1
10. Endif
12. YD = gdat$(1,PMONTH,PYEAR) - 1
14. End YD

to test the function execute something like that:

1. Infbox num$(func F_ENDMONTH(11,2015))