backwards incompatibility

[Dave Love]

Jerry DeLisle <jvdelisle@charter.net> writes:

> It would be an order of magnitude easier and take less time if you
> just recompiled all of your sources.  I hope you use make or cmake or
> at least some build scripting and let it run overnight.  Or, does it
> take a week or two?
>
> Regards,
>
> Jerry

[I saw this late on gmane as I'm not subscribed to the list.]

This isn't necessarily about "my" sources (stuff on local systems).  I
go with the engineering trades-off in packaging and late binding (in
this context) rather than combinatorial rebuild-the-world and distribute
packaging.

I'm specifically interested in RHEL (EPEL) packages, and concerned by
the lack of information on ABI compatibility of, say, gfortran 4.8 (the
system version) and gfortran 6 (the latest with the same libgfortan,
distributed for RHEL-like systems and necessary for several things like
proper MPI support and avx512).  Can someone say if 6 is (in)compatible
with 4.8 apart from the module format, assuming the same language
features?