Re: [gentoo-user] two glibcs with different version

[William Kenworthy]

On Sat, 2010-05-01 at 10:57 +0200, Kraus Philipp wrote:
>
> On 01.05.2010 um 10:32 wrote Volker Armin Hemmann:
>
> > On Samstag 01 Mai 2010, Graham Murray wrote:
> > > Kraus Philipp <philipp.kraus@×××××××××.de> writes:
> > > > Hello,
> > > >
> > > > I must test a software with a older version of the glibc. I run
> > > > the
> > > > 2.11.1 now but for one tool I need a previous version (2.6.1).
> > > > How can I compile the glibc without changing my system glibc. I
> > > > would
> > > > like to set the previous glibc with the LD_PATH.
> > > > Can I run two different versions or is a better solution to
> > > > downgrade
> > > > the system glib?
> > >
> > > I think that the only way you can do this is to create a chroot
> > > jail,
> > > in which you build everything using the old version of glibc (in a
> > > very
> > > similar way to building a new Gentoo system) and run your
> > > application in
> > > that.
> >
> > no, you can install glibc in /usr/local and then tell apps to either
> > use the
> > libs in /usr/local or /usr.
> >
> > It is just not easy because it easily breaks stuff in horrrible to
> > fix ways.
> >
>
>
> Okay, can I downgrade my glibc? My Gentoo isn't a big system, it's a
> server
> installation, so I can recompile the whole system. I had forgotten to
> mask the
> glibc on the last update. I have add a line to the portage.mask but
> emerge says
> that it can't compile the older version, because will damage the
> system.
>
>

Would LD_PRELOAD solve your problem? - worked for me when needing to run
a legacy redhat app in the past on a more up-to-date gentoo system. 

There is also a LD_LIBRARY_PATH variable.  Get a binary copy of the libs
you need and put em somewhere convenient and let the rest of the system
stay as is.

google for LD_PRELOAD.

BillK