ISO C++ WG21 meeting in Jacksonville, USA

The latest ISO C++ Standards Committee meeting, held in Jacksonville, Florida has now adjourned. The C++ Standards Committee, which is part of ISO, is responsible for development of the C++ standard. The face-to-face WG21 meetings are where changes to the standard are internationally discussed and voted on. These full week-long meetings take place two or three times per year and are usually attended by 90-120 people.

During the meeting, a variety of subgroups meet for technical discussions. These subgroups then decide on change recommendations to the standard, which are, by the end of the week, brought before the whole committee for approval. think-cell has been an active participant in this standardization process of C++ since 2013. For this particular meeting, think-cell sponsored Tony E. Lewis to attend the meeting to represent a paper that Arno Schödl, think-cell's CTO, and he co-authored.

The paper raised concerns about the proposed C++ Ranges library being incompatible with types not offering amortized constant time begin and end. Though it is desirable that these operations run in amortized constant time, the paper argued that by strictly requiring it, the ranges library excludes too large a design space of future standardization. Tony presented this paper to the Library Evolution Working Group (LEWG) on Tuesday, March 13, 2018. After debating the issues, the LEWG voted in favor of relaxing the constraints, whilst still allowing the Ranges library to rescind its complexity guarantees whenever the relevant complexity requirements are violated.

A paper is to be written to explore multiple candidate changes to wording. This is to be presented for discussion at the next standards meeting in Rapperswil, Switzerland, in June.