Re: Re: Best bikeshed ever (feature test macros)

[Rich Felker <dalias@aerifal.cx>]

On Wed, Aug 29, 2012 at 07:34:42AM +0200, philomath wrote:
> On Fri, 24 Aug 2012 17:41:38 -0400
> Rich Felker <dalias@aerifal.cx> wrote:
> 
> 
> > 1. Leaving everything as it is.
> 
> > 2. Making the kitchen sink (_GNU_SOURCE) available by default.
> 
> > 3. Making only some limited subset (e.g. POSIX base) available by
> > default.
> 
> The bikeshed should definitely not be colored black.
> 
> I'd lean towards 3, 1 is fine too. but please not 2, musl's
> correctness is one of it's unique features...
> 
> Thanks.

Thanks for the input. What correctness aspect is important to you? I
conceptually like the minimal-by-default namespace, but ISO C does not
specify how to invoke the compiler, so even implementations that
require you to use obscure options to get a clean plain-C namespace
are "correct". In practice, any of the options 1-3 would give the
clean namespace as long as -std=c* is used with no feature test
macros.

With that said, I do tend to agree that option 2 is ugly, mainly since
it exposes not just useful modern extensions but all kinds of ugly
legacy things, like sys/sysmacros.h junk getting pulled in from
standard headers... So far the most reasonable proposals I've seen are
along the lines of "XSI plus some extensions" where the latter would
correspond to _BSD_SOURCE or some analogue of _SVID_SOURCE (which is
not supported by musl at this time).

Rich