Re: autoconf check for AF_UNIX sockets

I wrote:

> > can our autoconf guru create a test for checking the availability of AF_UNIX
> > sockets? It could be defined in config.h as HAVE_UNIX_SOCKET or similar. It
> > will enable to use them in the newest cygwin where are this sockets
> > implemented.
> 
> I'll check into it.

A classical Autoconf test is impractical. First of all there's no reliable
compile-time evidence regarding these Unix sockets so we'd have to run a
program from configure. That's already a semi-no-no because it will break
cross-compilation and it also sounds a bit like a security concern.
Moreover, it's still doubtful whether you could learn a lot this way,
perhaps the user that runs configure cannot create these sockets or not
where configure is trying to create it, etc.

I have added a HAVE_UNIX_SOCKETS symbol into config.h.in that currently
checks !defined(__CYGWIN__) && !defined(__QNX__) in the accustomed manner.
You could extend it with specific Cygwin version checks.


-- 
Peter Eisentraut                  Sernanders väg 10:115
peter_e@gmx.net                   75262 Uppsala
http://yi.org/peter-e/            Sweden