[Bug c++/81239] std::__cxx11::string& visible in gcc warning output

[jg at jguk dot org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81239

--- Comment #8 from Jonny Grant <jg at jguk dot org> ---
(In reply to Jonathan Wakely from comment #7)
> (In reply to Jonny Grant from comment #5)
> > (In reply to Jonathan Wakely from comment #4)
> > > I fixed the std::__cxx11::string case on trunk, the output is now:
> > 
> > Great!
> > 
> > I wonder how this looks now with  -std=c++14    or -std=c++17 
> 
> Identical.
>  
> > (not sure why I still saw __cxx11 with both of these with my g++ 8.2.0
> 
> Because that namespace has absolutely nothing to do with any -std flag.
> 
> https://gcc.gnu.org/onlinedocs/libstdc++/manual/using_dual_abi.html

Ah ok, that makes sense now. I wonder how many people also confused by that. It
is a shame the GCC team did not give the namespace the name __abi11 instead, as
__cxx11 is just too similar to the C/C++ std names and gives an opportunity for
confusion.  If it happens again, would __abi be considered please.

Jonny