Gentoo Archives: gentoo-dev

From: "Jan Kundrát" <jkt@g.o>
To: gentoo-dev@l.g.o
Subject: Re: [gentoo-dev] How to support C++11 in libraries?
Date: Thu, 19 Dec 2013 15:17:51
In Reply to: Re: [gentoo-dev] How to support C++11 in libraries? by "Michał Górny"
1 On Thursday, 19 December 2013 10:18:55 CEST, Michał Górny wrote:
2 > Would it be possible to have a consistent ABI for both C++03 and C++11?
3 > The simpler changes like adding new fields can be backported quite
4 > easily (even if it would mean having dummy fields in C++03), I have no
5 > idea about the more complex changes.
7 I don't know, but from a bystander's point of view, I surely hope that it
8 will be possible. Otherwise there would be no option but providing a
9 multilib-like setup for C++11, after all.
11 Some messages on gcc's ML indicate that there are software vendors who are
12 *very* afraid of doing the SONAME change again. Given that C++11 forbids a
13 refcounted std::string while libstdc++ currently use just that for its
14 implementation, I suspect that the upstream developers have a very
15 interesting problem to solve. (And there's much more.)
17 It is pretty clear to me that even the gcc people have not reach a
18 consensus on how the ABI of the standard library will look like in 4.9, so
19 maybe it is premature for us to talk about how to solve this. The ball is
20 on their side.
22 > Well, if they considered the C++11 ABI in gcc-4.9 stable, we could
23 > consider changing the default to C++11. Then, we could do our
24 > bump/switch thing as a matter of gcc-4.9 upgrade problem.
26 To put things into perspective, *if* the ABI changes and if the new version
27 is compatible between C++98 and C++11, then we're talking something very
28 similar to an upgrade from GCC 3.3.
30 Cheers,
31 Jan


Subject Author
Re: [gentoo-dev] How to support C++11 in libraries? "vivo75@×××××.com" <vivo75@×××××.com>