Why shared libraries have version numbers

[Steve Langasek]

On Tue, Jul 07, 2009 at 02:59:16PM -0400, David Collier-Brown wrote:
>    I was being humorous: you're English is perfectly fine! 

>    I was suggesting the first thing you do is tell the programmer
> using two versions of the same library to not do that!

There's no reason to think that a programmer is involved at all.  This kind
of thing can happen when half of the reverse-deps of a library have been
rebuilt and the other have not; perhaps because the left hand doesn't know
what the right hand is doing, perhaps because someone didn't realize that
other bits of the system were using the library.  So this is usually the
work of sysadmins and distro packagers, not programmers.

The traditional soname system does a good job, overall, of preventing users
from winding up with broken combinations that give mysterious failures, but
this is one case where the traditional soname isn't enough to do the job.

-- 
Steve Langasek                   Give me a lever long enough and a Free OS
Debian Developer                   to set it on, and I can move the world.
Ubuntu Developer                                    http://www.debian.org/
slangasek at ubuntu.com                                     vorlon at debian.org