[oi-dev] gcc 5.3 testing

[Bob Friesenhahn]

On Fri, 13 May 2016, Alexander Pyhalov wrote:

> On 05/11/2016 22:22, Alexander Pyhalov wrote:
>> Hi.
>> I'm trying to build several components in oi-userland with gcc 5.3 to
>> find out which ones need fixing.
>> 
>
> One more issue we have to discuss... Updating gcc to 5.3 significantly breaks 
> C++ ABI - 
> https://gcc.gnu.org/onlinedocs/libstdc++/manual/using_dual_abi.html.
>
> As I understand, this means, C++ libraries should be recompiled to be used 
> with new code. What are we going to do with this? Mass recompilation and 
> message to the users "hey, we've broken ABI again..."? Do I understand this 
> correctly?

The way I read this, the old ABI is still supported by the 5.1+ 
library, GCC defaults to use the new ABI, but can be requested (or 
configured/hacked) to use the old ABI.

I also read that both ABIs can be supported simultaneously at the 
module level.  This assumes that ABIs can interoperate and it assumes 
that C++ code already built with an older GCC will continue to work 
without re-compilation with code compiled by GCC 5.1+.

If GCC 5.1+ is told to use the old ABI, it seems doubtful that C++ 
programs built with the new GCC will run with the standard C++ 
libraries supplied by earlier GCCs.

OmniOS has already introduced GCC 5.1 starting with r151016.

Bob
-- 
Bob Friesenhahn
bfriesen at simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer,    http://www.GraphicsMagick.org/