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Re: C++ constant expressions in __attribute__
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.)
--
Joseph S. Myers
joseph@codesourcery.com