Re: [boost] support for gcc hidden visibility in shared libraries

Subject: Re: [boost] support for gcc hidden visibility in shared libraries
From: Stjepan Rajko (stjepan.rajko_at_[hidden])
Date: 2008-12-05 08:56:51

On Fri, Dec 5, 2008 at 5:23 AM, Alexander Arhipenko <arhipjan_at_[hidden]> wrote:
> On Thu, Dec 4, 2008 at 10:39 PM, Stjepan Rajko <stjepan.rajko_at_[hidden]> wrote:
>>
>> Many (almost all?) linked boost libraries don't work as shared
>> libraries when compiled with the -fvisibility=hidden switch on gcc
>> version>=4.  I am wondering whether there is interest in making them
>> work under these circumstances, as it might not be too hard to do, and
>> there seems to be some benefit to it.
>>
>> [snip]
>
> Hi, Stjepan.
>
> There was thread on this topic some time ago, see:
> http://thread.gmane.org/gmane.comp.lib.boost.devel/177304
>

Ah, cool.

>
> I had even booked trac ticket and attached a patch (that provide gcc
> visibility facilities )
> to it, see:
> https://svn.boost.org/trac/boost/ticket/2114
>

The ticket has no owner - perhaps that is the problem?  To quote David
Abrahams from the thread above:

On Fri, Jul 11, 2008 at 5:11 PM, David Abrahams <dave <at> boostpro.com> wrote:
>
> patches tend to be more impactful when attached to Trac
> tickets: http://svn.boost.org ;-)
>

Perhaps Dave would like to take over the patch and make his statement
tend to be more true? ;-)

>
> I would really love to see such functionality in boost, but it was silence from
> the moment of ticket creation (~5 months ago) so I've became silent too ;).
>

Me too.  That ticket would have saved me 5 months of being baffled as
to why shared boost libraries don't work on one of my systems.

> Regards
>
> P.S. Comments on patch will be really appreciated

I think it's great, and I appreciate the extra bold step of actually
changing the compilation of affected libraries to build with hidden
visibility (had I made the patch, which I probably never would have
gotten to, I would have stopped short of that because of being afraid
of breaking something, but you probably know a lot more about all this
than me).  Three comments:
* the darwin toolset is affected the same way as gcc
* will the added -fvisibility=hidden cause a problem with gcc<4?
* I would prefer the slightly more descriptive macro names discussed
in the thread (I think BOOST_SYMBOL_EXPORT is my favorite)

Best,

Stjepan