Re: preparing for GCC 5, especially libstdc++6
On 06/25/2015 11:23 AM, Emilio Pozuelo Monfort wrote:
> Thanks for the report. I have looked at the wiki page, but it's not entirely
> clear to me how the libstdc++ transition will go, so I have a few questions to
> better understand it.
> - You suggest that some libraries may need to be renamed due to the ABI breaks.
> Do you have a list of affected libraries?
No. Getting this list is a bit difficult. Candidates for these packages are the
GCC 5 build failures due to mismatched symbols files. However there may be more
packages which successfully build, but have additional symbols (this may be an
empty set, because usually some symbol names should be just replaced by new ones).
> - Will those libraries need to migrate all at the same time with libstdc++, or
> could libstdc++/gcc-5 migrate first, and then the libraries can slowly migrate
libstdc++/gcc-5 can migrate first (and it already is). the dual ABI build only
adds an ABI, doesn't remove one). Depending on which packages really depend on
catching the std::system_error exception, and adding these to libstdc++6:Breaks,
you have a small set which may need transitioning at the same time. I was
talking with the boost maintainers to do a boost version bump at the same time.
> My main concern with all this is if we'll have a huge transition with lots of
> libraries been renamed and having to migrate at the same time with their rdeps.
yes, but I can't see a good way around it. What I heard from other distros is
that they handle this just with a rebuild. Of course Debian can do this as
well, but it probably will make partial upgrades not working.