[Bug libstdc++/68197] negative index to ios_base::iword lead to unpredictable result

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68197

--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> ---
No, it seems underspecified. I have raised it with the C++ committee.