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0 pointsgliptic9mo ago0 comments

Yes, but that's just a subset of expressions where unspecified sequencing applied. For instance, the example with two `print()` as parameters would have a sequence point (in pre-C++11 terminology) separating any reads/writes inside the `print` due to the function calls. It would never be UB even though the order in which the prints are called is still unspecified.

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gpderetta9mo ago

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).

glipticOP9mo ago

`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.

gpderetta9mo ago

(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.

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gpderetta9mo ago

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).

glipticOP9mo ago

`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.

gpderetta9mo ago

(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.

j / k navigate · click thread line to collapse