Re: AX_CXX_COMPILE_STDCXX fails to select default C++ standard automatically

Yuri <[email protected]> writes:
> Expected behavior:

>   * |AX_CXX_COMPILE_STDCXX| should automatically detect and use the
>     highest supported standard if the user does not provide any flags.

Is "highest supported standard" really the right decision rule?
I would personally have expected "use the compiler's default",
if no other guide is available.

The reason I'm leery of highest-supported-standard is that it carries
a nontrivial risk of breaking the build, when the package hasn't yet
been ported to -std=c++-latest-and-greatest.  If the compiler maker
isn't defaulting to that version yet, that's probably because they
are afraid it will break too much stuff.  I'd prefer to see autoconf
respecting that hopefully-well-chosen default, rather than blindly
forcing the latest thing.

			regards, tom lane