Re: [doc PATCH] update attribute docs for C++

[Sandra Loosemore <sandra@codesourcery.com>]

On 12/4/18 8:13 PM, Martin Sebor wrote:
> On 12/4/18 2:04 PM, Sandra Loosemore wrote:
>> On 12/4/18 9:26 AM, Martin Sebor wrote:
>>>
>>> [snip]
>>>
>>> +The keyword @code{__attribute__} allows you to specify various special
>>> +properties of types.  Some type attributes apply only to structure and
>>> +union types, and in C++, also class types, while others can apply to
>>> +any type defined via a @code{typedef} declaration.  Unless otherwise
>>> +specified, the same restrictions and effects apply to attributes 
>>> regardless
>>> +of whether a type is a trivial structure or a C++ class with 
>>> user-defined
>>> +constructors, destructors, or a copy assignment.
>>
>> And here I would really prefer to use standard terminology than trying 
>> to inaccurately summarize what the terminology means.  E.g.
>>
>> "...whether or not a class is trivial (in the C++11 sense) or POD (in 
>> C++98)."
> 
> This doesn't say what we want to say (nor is it accurate).
> 
> Here are the user's questions again:
> 
>    The documentation should clarify how it handles structs/
>    classes/unions and references.  Does it threat references
>    like pointers? Does it only allow PODs/trivial types to be
>    returned, or does it invoke the copy constructor, when it
>    is used again?
> 
> They were about const/pure but the same questions could be asked
> about other attributes as well.  The simple answer I'm trying to
> give is that it doesn't matter: (unless the manual says otherwise)
> references [to pointers] are treated the same as pointers, and
> there is no difference between functions that take arguments or
> return classes with user-defined ctors and plain old C structs,
> or between attributes applied to such types.  It doesn't help
> to use C++ standard terms when they are subtly or substantially
> different between C++ revisions, and then try to draw
> a distinction between those different terms, when they don't
> matter.

I'm getting even more confused about what you're trying to communicate 
here.  :-(

What is the "it" referenced in the user's questions you quoted?  The 
const/pure attributes?  Those are function attributes.  The text you are 
adding is in the type attribute section, so it seemed like it was trying 
to address a different problem: stating that you can attach type 
attributes to any struct/class type whether or not it is a "trivial" 
class, by some definition of that term.  If that's not the purpose of 
this paragraph, what is it?

-Sandra