[svlug] Downgrading a package in Debian

[Joey Hess]

Ivan Passos wrote:
> I need to downgrade my glibc from 2.1.3 to 2.0.7 in a Debian 2.2 (Potato)
> system, so that I can compile utilities for LRP (Linux Router Project) in
> it. How can I do that _safely_ using apt-get, dpkg, or the like??

Two options:

1. Build a copy of glibc 2.0 and put it somewhere that is not in the
   normal library search path. Override the normal path for linking and
   testing.
2. Install a chrooted debian system and build in there. You can find
   ready-made debian 2.1 chroots (with libc 2.0.7) at
   ftp://archive.debian.org/debian-archive/dists/Debian-2.1/main/disks-i386/current/base2_1.tgz 
   This is more convenient if you need to downgrade a number of
   libraries, not just libc.

> I'm guessing the answer will be "you can do it, but you'll break other
> glibc-2.1-based applications"... Pls tell me this is not true ... :))

Sorry, it's true. glibc is updards but not downwards compatable. That is
to say, programs built on glibc 2.0 that use only the public interfaces
will work with 2.1, 2.2, etc. But programs linked against 2.1 are not
guarenteed to work with 2.0.

-- 
see shy jo