No, that's the unportable camp, which doesn't have much following these days. Semi-portable basically means that you use #ifdef and similar techniques to contro

No, that's the unportable camp, which doesn't have much following these days. Semi-portable basically means that you use #ifdef and similar techniques to control the code that gets generated for the particular CPU and platform. To give one example, a lock-free ring buffer may have memory barriers that are #ifdef'ed out on x86 because you can rely on total store order. Similarly, `volatile` on MSVC can be expected to provide memory ordering guarantees (see https://docs.microsoft.com/en-us/cpp/cpp/volatile-cpp?view=msvc-160 https://docs.microsoft.com/en-us/cpp/cpp/volatile-cpp?view=m...).