[Development] abi breakage for qtwebengine libraries in 5.9

[Michal Klocek]

Thanks Thiago for the hint, I only tried to make symbols as weak alias, but that did not do the job. Now when you mentioned about default version I checked and symbols indeed were exported as 'default', I will try later today to see if this can be fixed as you suggested.


Br


Michal

________________________________
From: Development <development-bounces+michal.klocek=qt.io at qt-project.org> on behalf of Thiago Macieira <thiago.macieira at intel.com>
Sent: Monday, May 8, 2017 9:03 AM
To: development at qt-project.org
Subject: Re: [Development] abi breakage for qtwebengine libraries in 5.9

On Sunday, 7 May 2017 23:38:33 PDT Lars Knoll wrote:
> Hi,
>
> why can't we just keep these symbols around without exporting them through a
> header file and make them simply forward to the global new/delete
> operators? If we don't export them in a header at least newly compiled code
> would stop using them, and old code would continue working like that.

The problem is not related to compilation and thus headers.

The problem is that the symbols *exist*. Since they exist, the linker will
link to them.

Now, the problem is that they exist under an ELF version, so when we remove
them, the dynamic linker will no longer find the plain unversioned ones in
libstdc++.so.6. I *think* it's possible to provide them under as special type
of version that allows the previous uses to be found, but no longer allow new
linking to them (non-default version). But since I don't have qtwebengine
around, I need information:

Does _Znwm appear with one or two @ ?

--
Thiago Macieira - thiago.macieira (AT) intel.com
  Software Architect - Intel Open Source Technology Center

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