[cfe-dev] How to control C++0x adoption in a large codebase?

[John McCall]

On Oct 5, 2011, at 3:35 PM, Jeffrey Yasskin wrote:
> I'm working on migrating a certain large codebase to C++0x, and we're
> looking for a way to turn on C++0x mode but make sure people don't use
> C++0x features before we're ready for them.
> 
> * We need to turn on -std=gnu++0x for the whole codebase at once
> because C++98 and C++0x have different ABIs.

As far as I'm aware, this is not really true, and I actually put a lot of
effort into fighting a few committee proposals that would have forced
ABI changes.  There are a few things like name mangling which have been
changed/clarified in the Itanium ABI, and obviously the standard library
has to export more symbols in '0x, but I don't know of well-formed '03
programs that have changed.

Now, obviously you can break binary compatibility with macro
metaprogramming, but that's quite different.

Anyway, I'm not opposed to an extension warning for using '0x features.

John.