Re: Cross-platform availability of header files

[Ralf Corsepius]

On 03/15/2013 11:13 AM, Thomas Jahns wrote:
> On 03/15/2013 02:19 AM, Zack Weinberg wrote:
> > I've been doing research into the cross-platform availability of
> > header files that are commonly probed for in Autoconf scripts.
> > Results so far are here:
> > http://www.owlfolio.org/possibly-useful/notes-on-the-cross-platform-availability-of-header-files/
> >   Based on what I've learned, I have some questions for y'all:
>
> although you didn't ask: aio.h does not need to be probed for: unistd.h defines
> _POSIX_ASYNCHRONOUS_IO when it's available.
>
> See <http://pubs.opengroup.org/onlinepubs/007904875/basedefs/unistd.h.html> for
> some other features that don't require autoconf to check for, sys/mman.h is in
> the same category.

This is the description of an ideal world - Reality is a bit different.

aio.h and sys/mman.h are not available everywhere, nor are the _POSIX_* 
defines always correct, nor are the features these are supposed to 
provide available everywhere.

Ralf