[ub] [c++std-ext-14555] Sized integer types and char bits

Xavier Leroy Xavier.Leroy at inria.fr
Mon Oct 21 13:49:32 CEST 2013


On 2013-10-20 19:36, Gabriel Dos Reis wrote:
> b. It is not clear that the support for one's complement or sign-magnitude
>    adds a substantial complication, or that a substantial simplification
>    of the standards specification is to be gained from introducing that
>    requirement.  For example, I don't think support for these binary
>    representation would stop us from modifying the specification of
>    signed integer arithmetic overflow -- my take-away from the Chicago
>    meeting was that defining that be wrapping will be a very terrible idea
>    would meet opposition.

I understand that signed integer overflow is a hot issue and wasn't
expecting drastic changes in this department.

The kind of simplifications I had in mind is, for instance, the
specification of bitwise operators (~ & | ^ and shifts) over signed
integers, which is both complicated and imprecise in the current
standards, and would become simpler and fully specified if two's
complement was mandated.

- Xavier


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