Re: FYI: POSIX update - SIGWINCH and 'struct winsize' (etc) to be added

[Robert Elz <kre%munnari.OZ.AU@localhost>]

    Date:        Sun, 22 Oct 2017 05:59:41 +0200
    From:        Kamil Rytarowski <n54%gmx.com@localhost>
    Message-ID:  <1fba73e6-6ef5-ae30-4a3d-570db32fb01f%gmx.com@localhost>

  | As far as I can tell, if something defines a namespace like
  | _POSIX_SOURCE, it excludes _NETBSD_SOURCE. I've not researched the
  | source of this mechanism, but this is my observation and common in 3rd
  | party software.

Excludes by default, yes, it is from sys/featuretest.h (which is included
by just about every other standard header file.)

#if !defined(_ANSI_SOURCE) && !defined(_POSIX_C_SOURCE) && \
    !defined(_XOPEN_SOURCE) && !defined(_NETBSD_SOURCE)
#define _NETBSD_SOURCE 1
#endif

That's where the _NETBSD_SOURCE definition normally comes from.

I'm not sure that case is important for the current issue though, as if
something is specifically defining _POSIX_SOURCE (or one of the other 2)
then it certainly should not be using ioctl() and if there are such
applications, and we break them, well, good...

kre