C++20 approved, C++23 meetings and schedule update

A couple of interesting things happened in the ISO C++ world this week…

C++20 passed unanimously, on track to publish later this year

On Friday September 4, C++20’s DIS (Draft International Standard) ballot ended, and it passed unanimously. This means that C++20 has now received final technical approval and is done with ISO balloting, and we expect it to be formally published toward the end of 2020 after we finish a final round of ISO editorial work.

As always, we are not counting on ISO’s publication speed to call it C++20, it’s C++20 because WG21 completed technical work in February. If for some reason ISO needs until January to get it out the door and assigns it a 2021 publication date, the standard will still be referred to as C++20. That is already its industry name, and 300,000+ search hits can’t be (retroactively made) wrong!

ISO C++ meetings are virtual until further notice, Kona postponed

A month ago, I notified the committee that our face-to-face meetings will be postponed until further notice. We still need to plan for face-to-face meetings so that we’re ready to resume when that’s possible and safe, but for now all currently planned meetings should be viewed as “tentative.”

Among other constraints such as national and corporate travel restrictions, we are subject to face-to-face meeting bans from several parent organizations. Two of those extended or enacted face-to-face meeting bans this week, on Tuesday September 1:

• INCITS, the U.S. standards body, extended its face-to-face meeting ban through March 31, 2021. This means that our Kona meeting planned for February is now formally postponed to an unspecified future date.
• ISO SC22, our corner of the international organization for standardization that handles programming languages, resolved to ban face-to-face meetings of more than 100 people until further notice. Since our meetings lately have regularly seen over 200 attendees, we’re currently evaluating how this affects future post-Kona tentative meeting plans.

All of these bans are subject to further extension, and we won’t meet in person again until it’s safe to do so. As of this writing, our next tentative face-to-face meeting would be the rescheduled Varna meeting, in the first week of June 2021, but that should be viewed as the earliest possible resumption of meetings. As the pandemic develops and INCITS and ISO meeting bans and other restrictions are extended, it’s certainly possible that we may not be able to meet again in 2021 at all. We’ll see.

In the meantime, though, we’re still making progress on our work: For several years, we have already been holding regular virtual meetings for some of our subgroups, including study groups (SGs) and CWG and LWG (language and library specification wording). Since the pandemic started, EWG and LEWG (language and library evolution, our primary design subgroups) have also begun meeting virtually, and we are continuing to adjust our process for how to approve design changes to progress proposals while not meeting in person. And starting in November, we will begin having virtual plenary (whole-group) meetings to formally approve changes, including potentially new features, to the C++23 working paper…

C++23 schedule and priorities

The C++23 schedule (P1000R4) and C++23 priorities (P0592R4) are unaffected by the pandemic. You may find this surprising, but that’s because the committee is on a “train model” that focuses on schedule and priorities for each release, instead of a specific feature set. One of the benefits of the train model is that it is very resilient, and can handle even major disruptions without change. We have already been in the mode of working on features all the time, including long-pole features that take many years, and each regular release train includes “whatever’s ready” with the next train opening up as soon as the previous one ships. So, that is unchanged.

What has changed, of course, is the speed at which we can work on features during the coming period. The pandemic disruptions have impacted all our lives, and reduced the time and energy WG21 participants have for standards work as well as our capacity to make progress face to face three times a year, and this has slowed down development of features we’re working on now that will land in { C++23, C++26, C++29 } . No virtual process will fully compensate for the lack of intense week-long face-to-face meetings, but as usual we’ll continue to make progress on baking features according to the P0592R4 priorities, including issue resolutions and an emphasis on completing C++20, and as usual we’ll load each feature into the currently loading train as the feature becomes ready. So progress continues, and the trains will continue to run on time to ship everything that’s ready.

Of course, the ISO C++ committee isn’t the only part of the C++ world that has “gone virtual” this year. We’ve been enjoying many virtual conferences, and just a week from now we’ll start the biggest C++ conference of the year: CppCon 2020, all online. I look forward to seeing many of you there, including literally seeing you at the video chat tables and in my AMA Q&A session early in the week, and the Committee Fireside Chat panel on Tuesday.

Thanks for your interest in C++ and C++ standardization! Be safe, everyone.