CppCon 2019: Timur Doumler “Type punning in modern C++”

— Discussion & Comments: — Presentation Slides, PDFs, Source Code and other presenter materials are available at: — Type punning is often used in C for fast floating-point math, deserialising C objects from a sequence of bytes, and other purposes. Popular techniques involve unions, reinterpret_cast, and memcpy. C 20 provides new useful tools, such as bit_cast. And there are proposals to provide even better control over C object creation in the future. This talk is a comprehensive overview of all of these techniques. We will discuss when and how they can be used safely without causing undefined behaviour, what C does and does not allow you to do (and why), existing holes in the C language, and how to fix them. In the process, we will cover important C concepts such as object lifetime, value representations, and aliasing rules. — Timur Doumler Timur Doumler is a C developer