Re: missing libstdc++.6 symbol on the trunk

[Jonathan Wakely <jwakely dot gcc at gmail dot com>]

On 2 December 2010 12:55, Paolo Carlini wrote:
> On 12/02/2010 01:53 PM, Jonathan Wakely wrote:
>> http://gcc.gnu.org/viewcvs?view=revision&revision=166171
>> N3092 changed the definition of future_category, but IIRC I had
>> intentionally not changed our version because of the ABI implications.
>> ?We should probably do a backwards-compatibility fix so that
>> _ZSt15future_category is still exported with the correct symver.
>>
> Right, I just came to the same conclusion (and I don't see why the new
> symbol can't just be versioned @GLIBCXX_3.4.15). Are you willing to work
> on it?

Seems to be fixed by the attached patch, but I'd appreciate a review
from someone who understands the .symver directive better than me.

I used the @@@ form of .symver so that the symbol is renamed.  With
the @ or @@ forms the missing std::future_category symbol gets
exported, but it's a null pointer so programs using it can link but
crash if they dereference the pointer.  With @@@ we get the desired
behaviour and no crash (at least in my brief tests.)

        * src/future.cc (future_category): Export compatibility symbol.
        * config/abi/pre/gnu.ver: Move _ZSt15future_categoryv to 3.4.15
        version.

Tested x86_64-linux, committed to trunk.

Attachment: abi.txt
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