Set prolog flag: prefer_rationals

Pardon if this is a duplicate - I’m new to swipl forums. I set the prefer_rationals to true, the manual says that integer division (//) should produce a rational number but I’m getting 0 from X is 3//7.. Am I missing something? Thanks.

PS. Apologies if duplicate topic. I did search but didn’t find anything appropriate.

My bad. Misread the manual. Please ignore…