Re: [Boost-users] [system] symbol visibility and GCC vs. Clang

Subject: Re: [Boost-users] [system] symbol visibility and GCC vs. Clang
From: James Walker (jamesw_at_[hidden])
Date: 2012-10-23 13:40:42

On 10/23/2012 4:39 AM, Mathias Gaunard wrote:
> On 22/10/12 23:29, James Walker wrote:
>> When trying to link a bunch of libraries on OS X, I got this linker
>> warning:
>>
>> ld: warning: direct access in
>> boost::system::system_error::~system_error() to global weak symbol
>> vtable for boost::system::system_error means the weak symbol cannot be
>> overridden at runtime. This was likely caused by different translation
>> units being compiled with different visibility settings.
>>
>> As far as I can tell, everything is compiled using the flags
>> -fvisibility=hidden -fvisibility-inlines-hidden.
>>
>> I'm wondering whether the problem is that some of the libraries were
>> built using gcc and some were built using Clang.  In
>> boost/system/system_error.hpp, the declaration of
>> boost::system::system_error is decorated with BOOST_SYMBOL_VISIBLE.  In
>> boost/config/compiler/gcc.hpp, BOOST_SYMBOL_VISIBLE is defined to be
>> __attribute__((visibility("default"))), whereas
>> boost/config/compiler/clang.hpp does not define BOOST_SYMBOL_VISIBLE.
>
> This looks like a significant bug, POSIX-style symbol visibility doesn't
> work with Clang.
> Please file a ticket.

OK, thanks.  <https://svn.boost.org/trac/boost/ticket/7559>

-- 
   James W. Walker, Innoventive Software LLC
   <http://www.frameforge3d.com/>