Re: [PATCH] misra: add R14.4 R21.1 R21.2

[Jan Beulich <jbeulich@xxxxxxxx>]

On 26.10.2023 03:16, Stefano Stabellini wrote:
> On Wed, 25 Oct 2023, Jan Beulich wrote:
>> On 25.10.2023 03:15, Stefano Stabellini wrote:
>>> And if we can find a clear general comment about the usage of leading
>>> underscores in Xen I am happy to add it too (e.g. header guards), but
>>> from MISRA point of view the above is sufficient.
>>
>> But what we need isn't a description of the status quo, but one of
>> what state we want to (slowly) move to. The status quo anyway is
>> "no pattern, as in the past hardly anyone cared".
> 
> I guess you are suggesting something more like the following, but please
> feel free to suggest your favorite wording (it might be easier for me to
> understand what you mean if you provide a short example).
> 
> ---
> All identifiers starting with an underscore are reserved and should not
> be used.

Again, no. Identifiers starting with an underscore followed by another
underscore or an upper-case letter are reserved. Other identifiers are
dedicated for a particular purpose, and are fine to use for (at least)
that purpose.

> Today Xen uses many, such as header guards and bitwise
> manipulation functions. Upon analysis it turns out Xen identifiers do
> not clash with the identifiers used by modern GCC, but that is not a
> guarantee that there won't be a naming clash in the future or with
> another compiler. For these reasons we discourage the introduction of
> new reserved identifiers in Xen, and we see it as positive the reduction
> of reserved identifiers. At the same time, certain identifiers starting
> with an underscore are also commonly used in Linux (e.g. __set_bit) and
> we don't think it would be an improvement to rename them.

Everything else reads okay-ish to me.

Jan