Re: tail question

[Paul Eggert]

address@hidden (Paul Jarc) writes:

> This is unclear to me.  It sounds like what you mean is that the
> *spec* change predates 4.5.1, but the actually-exhibited *behavior*
> change is only a few months old.  Is that right?

I meant that the coreutils code itself introduced these changes before
4.5.1.  The actually-exhibited behavior therefore changed before then.
I've been using the new behavior for a couple of years myself, as the
default way that I use the standard utilities, because I set
_POSIX2_VERSION=200112 in my environment.

The only thing that's changed recently is the choice of the default
behavior if neither the installer nor the user specifies a preference.
In this case, coreutils looks at <unistd.h>'s _POSIX2_VERSION to
determine the system default.  Some implementations have recently
claimed (typically incorrectly, I guess) to conform to the POSIX
1003.1-2001 standard for utilities and have therefore set <unistd.h>'s
_POSIX2_VERSION to 200112L.  The coreutils build process by default
takes them at their word.

I typically use the latest Debian stable distribution (3.0r1).
It doesn't have this problem since its <unistd.h> says that
_POSIX2_VERSION is 199209L, which corresponds to POSIX 1003.2-1992.
But I gather that other, more bleeding-edge distributions claim
conformance to the newer POSIX standard.