Re: [gentoo-dev] How to support C++11 in libraries?

[Jan Kundrát]

On Friday, 20 December 2013 12:56:43 CEST, Sven Eden wrote:
> And no, the languages are _not_ "source-incompatible". That would be a
> scandal!

You might argue about this, but that doesn't change these facts. This is 
absolutely valid C++98 program:

jkt@svist ~ $ cat foo.cpp 
int main() {
    auto int foo;
    return 0;
}
jkt@svist ~ $ g++ -std=c++98 -pedantic foo.cpp
jkt@svist ~ $ echo $?
0

...which will *not* build under the C++11 mode:

jkt@svist ~ $ g++ -std=c++0x foo.cpp
foo.cpp: In function ‘int main()’:
foo.cpp:2:14: error: two or more data types in declaration of ‘foo’

Yes, -Wc++0x-compat warns about this, yes, it's included in -Wall, but it 
does not change the fact that there *is* code out there which does conform 
to C++98 standard, does *not* try to "outsmart the compiler", and which 
will not build in the C++11 mode. Do we really have to be having this 
discussion?

Cheers,
Jan