Hi, There were quite a few times when I wanted to use bitwise operations on atomic<enum>, where the enum lists a number of flags that could be combined with bitwise AND, OR and XOR. Neither std::atomic nor Boost.Atomic enables bitwise operations for enums, so I had to resort to workarounds, such as using atomic<underlying_type_t<enum>> with explicit casts to and from the underlying type of the enum. Obviously, this is rather tedious, and I would prefer not to have to do this. I'm not sure what was the original rationale for not allowing bitwise operations for std::atomic<enum>, but I would guess these points were a part of it: 1. Not all enums represent bit masks, so for some enums the bitwise operations wouldn't make sense. 2. There may be user-defined bitwise operators defined for an enum, and presumably atomic<enum> would not invoke them to implement atomic bitwise operations. (Because it is generally not possible to make an arbitrary user's operator implementation atomic, other than to wrap it in a CAS loop, which defeats the point of having a dedicated atomic operation.) Some users may find this surprising. 3. For some operations, there may be multiple reasonable implementations. For example, bitwise complement (operator~) may be inverting all bits in the enum representation or only those bits, for which there are named values. An atomic<enum> could possibly implement the former, but the user's operator~ could implement the latter, which would introduce a discrepancy in behavior. Also, ironically, if atomic<enum> attempted to solve the problem #1 by detecting presence of user-defined bitwise operators for the enum and took it as a sign that the enum is a bit mask, this would only emphasize the problems #2 and #3. So, clearly, on one hand the functionality could be useful in practice, and on the other hand there may be pitfalls and confusion coming from it. I wonder what people think about this. Would you prefer to have the support and deal with the consequences or the status quo? Perhaps, you had your own solutions to this problem? Maybe there are other strong reasons to not have it? Personally, I'm leaning towards having the functionality rather than not. You can always not use what you don't want or need, but not the other way around. Thanks.