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

Subject: Re: [boost] support for gcc hidden visibility in shared libraries
From: Alexander Arhipenko (arhipjan_at_[hidden])
Date: 2008-12-05 07:23:12

On Thu, Dec 4, 2008 at 10:39 PM, Stjepan Rajko <stjepan.rajko_at_[hidden]> wrote:
> Hello,
>
> 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.
>
> To my limited understanding, making a symbol visible in a shared
> library using, say, __attribute__ ((visibility("default"))) on gcc, is
> analogous to using __declspec(dllexport) on windows.   Many boost
> libraries already use macros that apply  __declspec(dllexport) on
> windows - so these macros could set to expand to __attribute__
> ((visibility("default"))) on gcc.  Even better, a boost-wide macro
> could be added to the config headers.
>
> More information on this can be found here:
> http://gcc.gnu.org/wiki/Visibility
>
> Just to note, I have very limited understanding of compiling/linking
> and I might not have a full grasp of everything involved here.  Also,
> my only reason for thinking that -fvisibility=hidden should be
> supported is that for a long time now, I haven't been able to use
> boost shared libraries on my os x platform, and only now I realized
> that the reason for this is that I had stuck -fvisibility=hidden in my
> user-config.jam a long time ago to suppress some warnings.
> Nonetheless, it seems like there are benefits to supporting it that go
> beyond preventing people like me from accidentally shooting themselves
> in the foot.
>
> Kind regards,
>
> Stjepan
>

Hi, Stjepan.

There was thread on this topic some time ago, see:
http://thread.gmane.org/gmane.comp.lib.boost.devel/177304

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

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 ;).

Regards

P.S. Comments on patch will be really appreciated