Let me clarify first that when I say "Linux" in this post, I'm specifically referring to the Linux kernel, not user-space software that runs on Linux. The Linu

Let me clarify first that when I say "Linux" in this post, I'm specifically referring to the Linux kernel, not user-space software that runs on Linux. The Linux kernel is written in C, but uses lots of GCC-specific features and inline assembly to address things that aren't covered by the C standard. Among these, the Linux kernel has its own set of atomic types and memory barriers. It documents them here: https://www.kernel.org/doc/Documentation/memory-barriers.txt https://www.kernel.org/doc/Documentation/memory-barriers.txt So even if Linux is being compiled on a conforming C11 compiler (the Linux kernel is written in C, not C++), it uses its own atomic primitives instead of the ones provided by the language. Hope that helps.