Gentoo Archives: gentoo-dev

From: "vivo75@×××××.com" <vivo75@×××××.com>
To: gentoo-dev@l.g.o
Subject: Re: [gentoo-dev] How to support C++11 in libraries?
Date: Thu, 19 Dec 2013 16:30:30
In Reply to: Re: [gentoo-dev] How to support C++11 in libraries? by "Jan Kundrát"
1 On 12/19/13 16:17, Jan Kundrát wrote:
2 > On Thursday, 19 December 2013 10:18:55 CEST, Michał Górny wrote:
3 >> Would it be possible to have a consistent ABI for both C++03 and C++11?
4 >> The simpler changes like adding new fields can be backported quite
5 >> easily (even if it would mean having dummy fields in C++03), I have no
6 >> idea about the more complex changes.
7 >
8 > I don't know, but from a bystander's point of view, I surely hope that
9 > it will be possible. Otherwise there would be no option but providing
10 > a multilib-like setup for C++11, after all.
11 >
12 > Some messages on gcc's ML indicate that there are software vendors who
13 > are *very* afraid of doing the SONAME change again. Given that C++11
14 > forbids a refcounted std::string while libstdc++ currently use just
15 > that for its implementation, I suspect that the upstream developers
16 > have a very interesting problem to solve. (And there's much more.)
17 >
18 > It is pretty clear to me that even the gcc people have not reach a
19 > consensus on how the ABI of the standard library will look like in
20 > 4.9, so maybe it is premature for us to talk about how to solve this.
21 > The ball is on their side.
22 >
23 >> Well, if they considered the C++11 ABI in gcc-4.9 stable, we could
24 >> consider changing the default to C++11. Then, we could do our
25 >> bump/switch thing as a matter of gcc-4.9 upgrade problem.
26 >
27 > To put things into perspective, *if* the ABI changes and if the new
28 > version is compatible between C++98 and C++11, then we're talking
29 > something very similar to an upgrade from GCC 3.3.
30 >
31 > Cheers,
32 > Jan
33 >
34 just a question, what would do -fabi-version=6 added to CXXFLAGS even
35 w/o C++11?


Subject Author
Re: [gentoo-dev] How to support C++11 in libraries? "Jan Kundrát" <jkt@g.o>