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Re: libc versioning question

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Lusotec <nomail@nomail.not> writes:
> Rainer Weikusat wrote:
>> Lusotec writes:
>>> Cat22 wrote:
>>>> I have a (precompiled) program that requires libc 2.11 but i only
>>>> have libc 2.10. Is it practical or even possible to put the 2.11 files
>>>> in some directory then run the program using the LD_LIBRARY_PATH
>>>> environment variable so it would use the 2.11 versions? I dont think you
>>>> can just upgrade libc and libstdc++ on my system without wreaking havoc
>>>> can you? I do some C programming from time to to time, but I have not
>>>> had to really ever consider the versions of these libs in the past so I
>>>> just dont know what can or cant be done there.
>>>> Thanks
>>>> Cat22
>>>
>>> Upgrading libc 2.10 to libc 2.11 (a minor version upgrade) should not
>>> cause any issues.
>> 
>> The problem with this is that the outcome of such an experiment isn't
>> known until after it was conducted and it is not usually reversible.
>
> If Cat22 only points the symlink /lib64/libc.so.6 to the new library, it 
> should be easy to reverse. I don't foresee any issues. On the Mandriva 
> systems I use and administer, the libcs have been updated many times without 
> any issues.

I had the mispleasure to deal with botched C library updates twice in
my life so far. One I did on an ancient, private RedHat or SuSE system
myself. A reinstall was required afterwards. And one a particularly
obtuse former colleague of mine tried to do on a production machine
serving as content-filtering appliance for a customer of the company I
worked for at that time. This time, the customer had to do the
reinstall according to directions I gave him on the phone. Needless to
say this company didn't remain a customer for much longer
afterwards. That was also already at a time when 'symbol versioning'
was supposed to have solved 'C library update issues' once and for
all. I'm not in the mood for Russian Roulette, no matter how much the
odds should be in my favor. This means that if I need a newer (or
different) version of the C library on some system (which occasionally
happens), I compile it myself and ensure that only the programs which
need it get linked with it.

NB: The major version of glibc was 'fixed forever' at 2 for political
reasons around 1998.

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libc versioning question Cat22 <cat22@invalid.org> - 2012-02-26 15:51 -0800
  Re: libc versioning question Lusotec <nomail@nomail.not> - 2012-02-27 12:31 +0000
    Re: libc versioning question Rainer Weikusat <rweikusat@mssgmbh.com> - 2012-02-27 16:15 +0000
      Re: libc versioning question Lusotec <nomail@nomail.not> - 2012-02-27 17:23 +0000
        Re: libc versioning question Cat22 <cat22@invalid.org> - 2012-02-28 00:49 -0800
        Re: libc versioning question Richard Kettlewell <rjk@greenend.org.uk> - 2012-02-28 09:24 +0000
        Re: libc versioning question Rainer Weikusat <rweikusat@mssgmbh.com> - 2012-02-28 14:47 +0000
  Re: libc versioning question John Reiser <jreiserfl@comcast.net> - 2012-02-28 08:06 -0800

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