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Re: is the whole unstable still broken by gcc-5?

On 13/09/15 10:34, Samuel Thibault wrote:
> Svante Signell, le Sun 13 Sep 2015 11:33:31 +0200, a écrit :
>>> That's what Sid/Unstable is used for. You'll have to live with that :)
>>> This transition was IMHO a monster compared to the usual transitions
>>> and it might happen again. Se at the end we probably should discuss,
>>> what to improve next time.
>> What about transition to glibc-2.21?
> glibc has been systematically using compat symbols since a looong time
> (the libc5 -> libc6 transition).

The problem with the g++-5 transition is not libstdc++ itself -
libstdc++ has various tricks to be compatible with both ABIs.

The unusual problems with the g++-5 transition are:

* merely recompiling some other library with the new compiler, without
  making any source changes in that library, changes its ABI;
* it isn't immediately obvious whether a library is using the old or
  new ABI;
* it isn't immediately obvious whether the new ABI even makes any
  difference for a particular library;
* the packages whose ABI does change include apt and schroot, which
  are key development tools;
* hundreds of packages' ABIs changed;
* the new compiler makes some things FTBFS;
* and the transition is entangled with moving to a new version of Boost
  which also makes some things FTBFS.

Ordinary library transitions are easy by comparison.


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