noalias macro bug [was: Linux and aliasing?]

[Jamie Lokier]

Mark, thank you.

> No.  There's *no* conformant way to do the kind of thing Linus wants,
> except to use memcpy, or other means of copying through a char*.

>     Jamie> I still don't get the wording.  Do you mean "permitted to
>     Jamie> access *any objects with the same type* as the unionized
>     Jamie> fields"
> 
> Yes.

So we are talking about `noalias' using a GCC-specific extension then.
Namely, the type-aliasing behaviour of access through unions.

>     Jamie> I'm worried when you say `noalias' is outside standard
>     Jamie> behaviour, since it means we're depending on undocumented
>     Jamie> GCC-specific behaviour.  Clearly we don't want to do that.
> 
> Then you have to use memcpy.

Or document the GCC-specific behaviour.

-- Jamie