This year, CppCon 2020 is going virtual. The dates are still the same – September 14-18 – and we are aiming for the CppCon live event to have pretty much everything you’re familiar with at CppCon except moved online: multiple tracks including “back to basics” and a new “embedded” track; live speaker Q&A; live talk time zones friendly to Americas and EMEA (and we’re going to try to arrange around-the-clock recorded repeats in all time zones, where speakers who are available can be available for live Q&A in their repeated talks too, and we’ll do that if it’s possible – but we’re still working on it!); virtual tables where you can interact face-to-face online with other attendees just like at the physical event; virtual exhibitor spaces where you can meet the folks on your favorite product’s teams to ask them question face-to-face; pre- and post-conference classes; and even the CppCon house band playing live before every plenary session. All talk recordings will be freely available as usual on YouTube a month or two after the event, but everything else above will be available only live during CppCon week.

To whet your appetite for this year’s conference, here’s another of the top-rated talks from last year. Enjoy – and register today for CppCon 2020 – all the spirit and flavor of CppCon, this year all virtual and online!

std::midpoint? How Hard Could it Be?

by Marshall Clow

Summary of the talk:

The standards committee adopted "P0811: Well-behaved interpolation for numbers and pointers" for C++20.
It includes a new library call `std::midpoint`.
The paper says "The simple problem of computing a value between two other values is surprisingly subtle in general."

In this talk, I will explore this simple call, provide a history of the development in libc++, and show some of the pitfalls.
Undefined behavior will rear its ugly head, along with numeric representations, and the arcane C promotion rules.

Along the way, we'll talk about testing, and why writing extensive tests helps everyone.