Re: Re: [alpine-devel] Non-standard C library

[Rich Felker <dalias@libc.org>]

On Tue, Jan 31, 2017 at 01:08:07PM -0600, A. Wilcox wrote:
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> On 31/01/17 12:50, William Pitcock wrote:
> > On Tue, Jan 31, 2017 at 12:22 PM, Harald Arnesen 
> > <harald@skogtun.org> wrote:
> >> musl defines "IPPORT_RESERVED" in "netdb.h", while both GNU libc 
> >> and BSD libc define it in "netinet/in.h". And I can't find an 
> >> e-mail address for a musl developer without subscribing to their 
> >> mailing list.
> 
> 
> POSIX.1-2008 clearly says IPPORT_RESERVED shall be defined in <netdb.h>:
> http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/netdb.h.html
> 
> .....
> 
> 
> > I checked on both a Debian and FreeBSD machine and indeed, they 
> > both have it in netinet/in.h.
> 
> .....
> 
> however, POSIX.1-2008 also clearly says <netdb.h> "may also make visible
> all symbols from <netinet/in.h>".
> 
> 
> > What shall we do?
> 
> 
> Theoretically, the code they are compiling is wrong; POSIX only
> guarantees the definition in <netdb.h>.  However, there is a bit of
> leeway in the standard since <netdb.h> may include all symbols from
> <netinet/in.h>; if it's defined there, <netdb.h> can pull that header
> in providing the definition.
> 
> I would say that the best thing to do in the interests of
> compatibility would be to put the definition in <netinet/in.h> *and*
> fix whatever broken project that is (Snobol?) to include <netdb.h>.
> This is what FreeBSD and glibc both do; define it in <netinet/in.h>
> and include that header in <netdb.h>.

The name IPPORT_RESERVED is not reserved in the namespace for
netinet/in.h, so it can't be added there unless it's conditional on
nonstandard feature profile. That might be justifiable if lots of
applications had the wrong expectation here, but being that this is
the first time we've heard of the issue, it seems there are just a few
(or only one) applications which are doing this wrong, and they should
just be fixed.

Rich