Hi, I have a rare numeric for loop variable behavior in LuaJIT 2.0.2: local N = 4 for i = 1, N do if i < 0 or i > 4 then print(i, N) -- Is this possible ?? end end Yes, It really happened a couple of times a week in my project, I got i = 5 and N = 4 ! How did it happen? Could someone give me some clues/hints? Thanks. Cheyi