Documenting common C/C++ options

[Florian Weimer]

* Richard Earnshaw:

> On 10/10/2023 11:46, Richard Earnshaw (lists) via Gcc wrote:
>> On 10/10/2023 10:47, Florian Weimer via Gcc wrote:
>>> Currently, -fsigned-char and -funsigned-char are only documented as C
>>> language options, although they work for C++ as well (and Objective-C
>>> and Objective-C++, I assume, but I have not tested this).  There does
>>> not seem to be a place for this kind of options in the manual.
>>>
>>> The options -fshort-enums and -fshort-wchar are documented under
>>> code-generation options, but this seems to be a bit of a stretch because
>>> (at least for -fshort-wchar), these too seem to be more about front-end
>>> behavior.
>>>
>>> What would be a good way to address this?
>>>
>>> Thanks,
>>> Florian
>>>
>> 
>> 
>> All of these are ABI; so where ever it goes, it should be documented
>> that changing them will potentially cause issues with any
>> pre-compiled object files having different settings.

> And you can add -f[un]signed-bitfield to that list as well.

There's already a section for those ABI options that are like
-fshort-enums:

@node Code Gen Options
@section Options for Code Generation Conventions

Maybe we should move them over there.

But that wasn't really the direction of my question.  I was wondering
where we should document a future C version of -fpermissive.

Thanks,
Florian