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Subject: [boost] Fwd: Re: [system] symbol visibility and GCC vs. Clang
From: Mathias Gaunard (mathias.gaunard_at_[hidden])
Date: 2012-10-25 08:19:29

-------- Original Message --------
Subject: Re: [system] symbol visibility and GCC vs. Clang
Date: Tue, 23 Oct 2012 10:40:42 -0700
From: James Walker <jamesw_at_[hidden]>
Reply-To: boost-users_at_[hidden]
To: boost-users_at_[hidden]
CC: Mathias Gaunard <mathias.gaunard_at_[hidden]>
Newsgroups: gmane.comp.lib.boost.user
References: <5085BABE.9030609_at_[hidden]>

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. <>

   James W. Walker, Innoventive Software LLC

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