misc/156637: sys/types.h can't be included when _XOPEN_SOURCE is defined

[Robert Andersson]

The following reply was made to PR misc/156637; it has been noted by GNATS.

From: Robert Andersson <streambag at streambag.se>
To: Garrett Wollman <wollman at hergotha.csail.mit.edu>
Cc: freebsd-gnats-submit at freebsd.org
Subject: Re: misc/156637: sys/types.h can't be included when _XOPEN_SOURCE
 is defined
Date: Wed, 27 Apr 2011 21:22:55 +0200

 On Mon, 25 Apr 2011 13:51:31 -0400 (EDT)
 Garrett Wollman <wollman at hergotha.csail.mit.edu> wrote:
 
 > >When including <sys/file.h> with _XOPEN_SOURCE defined to 500 or
 > >higher, compila tion will fail with a message similar to this one
 > >(using clang, gcc fails with a
 > > similar message):
 > 
 > Which edition of the standard specifies <sys/file.h>?  It's not in my 
 > copy of Issue 6 (SUSv3) or Issue 7 (SUSv4). 
 >  
 > I'd say it's the application code that is in error.  It should not be
 > defining _XOPEN_SOURCE and then including (implementation private)
 > header files which are not defined in the relevant standard.
 > 
 > Do we seriously need to start writing our headers like:
 > 
 > #include <sys/cdefs.h>
 > #ifndef __BSD_VISIBLE
 > #error "This is a non-standard header, but you have specified strict
 > standard compliance." #endif
 > 
 > ?  This probably goes along with my fix to <sys/cdefs.h> which does:
 > 
 > #ifdef __BSD_VISIBLE
 > #error "Application defined preprocessor macro in the implementation
 > namespace." #endif
 > 
 > -GAWollman 
 > 
 
 I think you are right. I was confused about what _XOPEN_SOURCE meant.
 
 By the way, I solved the problem by making sure that the
 application only uses standardized headers. In this case it meant using
 fcntl instead of flock. Hopefully, I will be able to push that upstream.
 
 As far as I'm concerned, this PR can be closed. Thanks for your help
 and sorry for the noise.
 
 / Robert