Re: libstdc++ compatibility frustrations under linux x86


You didn't describe what the problem is; not even its symptoms.
All we have is "acts weird"; not much help could be provided with
that problem description :-(


I didn't even realise myself at the time of writing what the problem
actually was.
Sorry for not being precise.

However now I'm a little smarter.

It turns out so far to be a problem with libgcc.
Currently libgcc is not being relinked with the library. This means that it
depends on the libgcc version running with the compiler used to link the
library.
In the current case the library it self is compiled with gcc 3.4.6 and being
linked with 3.3.6.

When end-users are using the final application with libgcc.so of version
3.3.6 then the library fails deep inside.
When they use a newer version of libgcc then it works.
So you ask what does "not work" mean? Essentially the library is doing wrong
computations which results in a wrong result.
It is running a sequence with known input giving a known output. When a
newer version of libgcc is used then it works. If version 3.3.6 is used then
it fails.

My suspecion is that the different versions of libgcc doesn't have binary
compatibility even though the symbols are the same. After all the
application is linked without problems.

The next step is to work with the users to re-link libgcc and see if it does
a difference. However that has not yet happend.

I didn't consider that it was necessary to relink libgcc though.
This seems to be the only logical explanation though (as far as the reports
I've received from users so far).

Thanks.

-- Henrik


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