An updated draft
of P2572R0 (std::format() fill character allowances) is now
The following changes have been made relative to the previously
- The proposal was modified to align with the outcome of our last
review. It now seeks to standardize the behavior exhibited
by gcc and MSVC.
- Wording was updated to align with the proposal direction.
- The character examples were extended to include the delete
character and a right-to-left directional character (Hebrew
- The "Estimated display width restrictions" section was
expanded to discuss the option of producing an error only when
the requested field alignment cannot be achieved.
- The "Existing practice" section was updated to include
character names, example behavior for the delete and Hebrew
letter tav characters, and an additional note about handling of
- The "Existing practice" section was updated to note that the
previously reported buffer overflow that occurs with MSVC 19.31
has been fixed for the next release and to include an example of
the diagnostic that is now issued.
- A new "Future considerations and ABI" section has been added.
- The "Implementation experience" section has been updated to
note that, now that the paper seeks to standardize the current
gcc and MSVC behavior, that the proposal has been implemented
(with the exception of some possible ABI break mitigations that
may or may not be misguided).