can 4.2 and 4.3 be mixed

[Janne Blomqvist]

On 6/25/07, Kamaraju S Kusumanchi <kamaraju@bluebottle.com> wrote:
> I have a very basic question. Till recently I was using gcc 4.2, gfortran
> 4.2. I have compiled lot of libraries (fftw3, mpich2, lapack, blas etc.,)
> with these. Now of late, I discovered a problem with gfortran 4.2 (
> http://gcc.gnu.org/ml/fortran/2007-06/msg00381.html ) but was fixed in
> gfortran 4.3 . So I am now using gcc 4.3, gfortran 4.3.
>
> My question is that, can I use gcc 4.3, gfortran 4.3 etc., and link the
> executables with libraries compiled using gcc 4.2, gfortran 4.2?

Official answer: no.

> It seems
> to be working for now. But I am not sure if it will give me problems in the
> long run. Any ideas?

In principle there are no guarantees about compatibility. However, if
you're lucky it might work just fine. At the moment 4.3 is not too
different than 4.2, but likely you will start seeing more problems as
4.3 diverges from 4.2.

> There are lot of libraries and I wish to avoid recompiling all these if I
> can get away with it. Any ideas/suggestions/pointers are very welcome.

Well, as of 4.3 the library uses symbol versioning, so hopefully we'll
do better in the future. That being said, ABI compatibility can be
somewhat tricky, so IMHO the safest option is always to have
everything compiled with the same compiler and version.

-- 
Janne Blomqvist