Re: Some question regarding tail and option "-c"

[Jim Meyering]

Robert Milasan wrote:

> On Thu, 04 Oct 2012 10:14:15 +0200
> "Jim Meyering" <address@hidden> wrote:
>
>> You can check by seeing how lib/posixver.c is compiled or by running
>> a command like the following.  Here's what I see on Fedora 17 and
>> newer:
>>
>>     $ gcc -x c -dD -E -include unistd.h /dev/null \
>>       |grep -E 'fine _?_POSIX2_(THIS_)?VERS'
>>     #define __POSIX2_THIS_VERSION 200809L
>>     #define _POSIX2_VERSION __POSIX2_THIS_VERSION
>>
>> When in doubt, you can use gdb to trace through the code, too.
>>
>
> This is the output:
>
> gcc -x c -dD -E -include unistd.h /dev/null |grep -E 
> 'fine_?_POSIX2_(THIS_)?VERS'
> #define __POSIX2_THIS_VERSION 200809L
> #define _POSIX2_VERSION __POSIX2_THIS_VERSION

I suggest you use gdb to see what the posix2_version function
returns, and why.  Suse may have chosen to build coreutils with the
DEFAULT_POSIX2_VERSION envvar set in such a way that tail's obsolete
behavior is the default.