C23 and stdatomic.h

March 5, 2025

C23 #

C23, formally ISO/IEC 9899:2024, is the current open standard for the C programming language, which supersedes the prior C17 (standard ISO/IEC 9899:2018).

Like other editions of the C standard, the official ISO text of the standard is not freely available, but the working draft N3220 (officially described as a draft of the future version “C2Y” of the C standard) was made public - differing only by a fix to one footnote compared to the latest C23 draft.

• https://en.wikipedia.org/wiki/C23_(C_standard_revision)
• ISO/IEC 9899:2024 (en) — N3220 working draft

Chapter 7.17: Atomics (stdatomic.h) #

The header <stdatomic.h> defines several macros and declares several types and functions for performing atomic operations on data shared between threads.

• stdatomic.h https://github.com/gcc-mirror/gcc/blob/master/gcc/ginclude/stdatomic.h
• https://pubs.opengroup.org/onlinepubs/9799919799/basedefs/stdatomic.h.html

These are the references to consider if you wish to make use of atomics in plain, contemporary C. There are several useful tutorials around.