Re: Selecting a C++ standard

[Harlan Stenn]

Adrian Bunk writes:
> On Sat, Oct 27, 2012 at 10:47:50PM +0100, Roger Leigh wrote:
> > Maybe have an optional argument to AC_PROG_CC_STDC to select
> > the standard e.g.
> >   AC_PROG_CC_STDC([C99])
> > ?

I like this idea.

> Latest discussion result was that there is no downside of setting the
> compiler to the highest mode possible.

Then that discussion was incomplete.

If I must ensure that a package requires a given "level" of STDC, then
configure MUST NOT decide any other "level" is OK.

> And as said above, feature testing is a separate issue.

that doesn't mean it is by definition OK to ignore this point.

> > I originally wrote AC_PROC_CC_C99 because it was several years
> > since GCC supported C99, but there was no portable way to use
> > C99 features with projects using autoconf unless you added
> > horrible hacks.  We still have this situation for C++, and it
> > would be nice to solve it in a similar way to C.  I'm happy to
> > go with the new approach of a single macro, but I would be
> > interested to understand how the issues I outlined above square
> > with this.
> 
> The main worry would actually be whether a compiler in C++11 mode might 
> reject any existing C++03 code.

I submit you are still ignoring the other side of the problem, which
says "Make sure I am using a C++03 compiler so I can be sure that the
package builds with a C++03 compiler if that is all *somebody else* has."

H