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I see it decently often in embedded code for memory mapped IO registers. Other than that, I don't think I've ever seen it either. I'm not sure portability is t

I see it decently often in embedded code for memory mapped IO registers. Other than that, I don't think I've ever seen it either. I'm not sure portability is the reason though. I've seen it in places that have no problem spamming #define __GNU_SOURCE

nomel 1y ago
This is the only place I've seen it used, and the only placed I've used it. It's absolutely wonderful for IO.
mort96 1y ago
I would be scared of using it for IO... With a struct bit field, I don't know what bit offset a field ends up with, I don't know how it gets padded, and I don't know how large the generated load and store becomes. I'd rather do the bit operations and store myself.
- gizmo686 1y ago
  __attribute__((packed)) is pretty much required for this use case.
  - mort96 1y ago
    That gets rid of the padding issue, but still does little to tell me which bit corresponds to which field.