Re: Updated: gcc-5.2.0-1 (Test x86/x86_64)

[cyg Simple <cygsimple@gmail.com>]

On 9/30/2015 7:36 PM, David Stacey wrote:
> On 30/09/15 23:34, JonY wrote:
>> On 10/1/2015 00:05, David Stacey wrote:
>>> On 30/09/15 12:15, JonY wrote:
>>>> gcc-5.2.0-1 has been uploaded for 32bit and 64bit Cygwin.
>>>>
>>>> This is the first series of the 5.x releases, and should be considered
>>>> as experimental as such.
>>>
>>> Have you managed to work around the ABI change in gcc-5 [1], or will
>>> this require a mass rebuild at the point gcc-5 becomes 'current'?
>>>
>>> [1] -http://developerblog.redhat.com/2015/02/05/gcc5-and-the-c11-abi/
>> As far as I know, every gcc release will break C++ ABI, so it would mean
>> rebuilding everything C++.
> 
> According to the Red Hat blog above, the last time g++ caused an ABI
> change was back in the 3.x days, so it hasn't happened for a while. Ah
> well, we have maintainers for most packages in Cygwin, so we'll have to
> co-ordinate a rebuild.

Regardless, JonY is correct.  Every C++ release, regardless of the
vendor, causes an ABI break with shared libraries and the naming of the
object elements (mangled names).  It is the nature created by technical
reason.  Not to mention that the first paragraph of the release states
that there is an ABI break.  And then there is this paragraph: "So the
plan for this ABI change has been to leave the soname (and the existing
binary interface) alone, and express the new ABI using different mangled
names."

-- 
cyg Simple

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