> On Oct 14, 2025, at 08:12, Tom Lane <[email protected]> wrote: > > Chao Li <[email protected]> writes: >> Look at this instance. The comment says: > >> * LZ4 equivalent to feof() or gzeof(). Return true iff there is no >> * more buffered data and the end of the input file has been reached. > >> It just states when the function should return true. In this case, why “if” >> is not good enough and “if and only if” is needed? > > Saying "if" here wouldn't fully specify the behavior. As an example, > returning constant-true would formally satisfy such a definition. > Yeah, most people would understand what is meant, but if you want > to be precise then you must make clear that the function doesn't > return true when the condition is not satisfied. > > I believe that the abbreviation "iff" arose among mathematicians, > who are much more likely to be concerned about such precision than > many of us. > > regards, tom lane
Okay, I see. In other words, if we were replacing “iff”, “only when” would be more precise than “if”. I think we can leave existing “iff” there. I withdraw this patch. Best regards, -- Chao Li (Evan) HighGo Software Co., Ltd. https://www.highgo.com/
