Re: C++ constant expressions in __attribute__

[Gabriel Dos Reis <gdr at integrable-solutions dot net>]

On Sat, Mar 7, 2009 at 4:45 PM, Joseph S. Myers <joseph@codesourcery.com> wrote:
> On Sat, 7 Mar 2009, Gabriel Dos Reis wrote:
>
>> May I forward your message to the CCC++ CWG?
>
> Certainly, it is a public message, as are all the previous discussions it
> references. ?I have not tried to engage with the C++ committee directly
> since I am not a C++ expert and keeping up with C development and pointing
> out (on the reflector and as needed in WG14 papers) when mistakes appear
> to be being made there is quite enough.
>
> (Also, the points I make are influenced by the general acceptance in WG14
> that a major mistake C99 made was inventing new features and standardising
> existing ones in ways that were *similar but different* to existing
> implementations, through lack of understanding of the existing features,
> so causing very slow adoption of C99 and compatibility problems down the
> line, e.g. C99 versus GNU inline. ?This was accepted in writing the C1x
> charter, but C++ may have different views on invention and compatibility.
> The choice of [[]] syntax does at least mean that __attribute__ can do one
> thing compatible with GNU practice and [[]] can do another thing as
> described in C++0x, but such a difference is bound to be confusing to
> users compared to making sure that attributes placed in the common subset
> of positions in the syntax have standard semantics that accord with
> existing practice.)

OK.  I believe semantics differences matter a lot.
My understanding is that the __attribute__ is found yucky
for some people, hence the [[]] syntax.

-- Gaby