[gpderetta]

IIRC the point was that there was no sequence point between argument evaluation, so for example f(++i, ++i) was UB. Or maybe it was only for builtin operators?

Cppreference is not authoritative[1], but seems to support my recollection. In fact it states that the f(++i, ++i) was UB till C++17.

[1] https://en.cppreference.com/w/cpp/language/eval_order.html, Pre C++11 Ordering Rules, point (2).

[gliptic]

`f(++i, ++i)` is/was indeed UB, but the example in munificent's comment was `foo(print(1), print(2))` which as far as I know is not even if both `print` calls read/write the same memory.

[gpderetta]

(5) in the paragraph I mentioned earlier seems to prevent interleaving of function calls, which admittedly would make the language hard to use. So I think you are right.