Re: Proposed semantics for attributes in C++ (and in C?)

["Joseph S. Myers" <joseph at codesourcery dot com>]

On Sun, 15 Oct 2006, Mark Mitchell wrote:

> We have a number of C++ PRs open around problems with code like this:
> 
>   struct S {
>     void f();
>     virtual void g();
>   };
> 
>   typedef __attribute__((...)) struct S T;

I was happy with the state before r115086 (i.e. with it being documented 
that such attributes on typedefs are ignored).  But given that we are now 
attempting to honour them, the proposed semantics seem reasonable.

The proposal requires documentation for each (type) attribute of whether 
it is semantic or non-semantic.  In general the documentation of attribute 
semantics needs cleaning up to make clear just when each attribute can be 
used and what exactly it means (and the code needs cleaning up to follow 
sensible documented semantics) - for example, attributes with 
documentation split and duplicated because they apply to more than one of 
functions, variables and types.  (The syntax documentation is cleaner, and 
I think accurate for C, but it does include some speculative future 
possibilities that seemed nice when I first wrote it but I no longer think 
would be a good idea.)

-- 
Joseph S. Myers
joseph@codesourcery.com