Re: [Boost-users] 'Multiply defined' errors in Boost 1.38.

22 Feb 2009

      Hi Volodya

The two boost libraries that cause problems are boost/test and
boost/lambda, and if I remove them all is fine in this example.

The problem only appears with <link>static.  If there is no <link>static
requirement then I get an error message saying that the bio-pch.h.gch is
not used because BOOST_SYSTEM_DYN_LINK us defined.  I assume that this
means that precompiled headers are incompatible with dynamic link
builds, although this does not appear to be mentioned.

If I define the exe as below in a static build the precompiled header
builds with no problems and the code links with no errors.  I suspect
that by not having the pch as a source this means it is not working as a
pch however

exe nigel
        :
                Lexer/BiobaseLexer.cpp
                Lexer/ArrayLexer.cpp
                #/boost/filesystem//boost_filesystem
                main_nigel.cpp
        :
                <variant>static:<source>bio-pch
                <library>/boost/system//boost_system
        ;

And apologies about the misleading header on my first posting.

Nigel Dyer
PhD student
MOAC Doctoral Training Centre
University of Warwick
Coventry
CV4 7AL

-----Original Message-----
From: boost-users-bounces@lists.boost.org
[mailto:boost-users-bounces@lists.boost.org] On Behalf Of Vladimir Prus
Sent: 22 February 2009 09:36
To: boost-users@lists.boost.org
Subject: Re: [Boost-users] 'Multiply defined' errors in Boost 1.38.

Dyer, Nigel wrote:
...
Hi
There is a problem with the 1.38 release of Boost that is preventing
me
from compiling using gcc on a mac some code that compiled correctly in
previous releases.  I now get lots of 'multiply defined' error
messages
when certain boost header files are included in specific ways, e.g.
/usr/libexec/gcc/i686-apple-darwin8/4.0.1/ld: multiple definitions of
symbol boost::test_tools::(anonymous namespace)::check_is_close
bin/darwin-4.0.1/release/link-static/threading-multi/Lexer/BiobaseLexer.
...
o definition of boost::test_tools::(anonymous
namespace)::check_is_close
in section (__DATA,__common)
bin/darwin-4.0.1/release/link-static/threading-multi/Lexer/ArrayLexer.o
...
definition of boost::test_tools::(anonymous namespace)::check_is_close
in section (__DATA,__common)
I have attached minimal example which seems to reproduce the problem.
It seems to be associated with the change that was introduced in svn
release r49800.
(https://svn.boost.org/trac/boost/changeset?new=49800%40trunk&old=49793%
...
40trunk)
I have run bjam -n -a with and without r49800 and also bjam with and
without the r49800 change, which appears to show that the problem
arises
after the change has been introduced:
Hi Nigel,

thanks for a comprehensive bug report. On the first look, it appears
that
Boost.Build change is actually right -- it fixes a previously introduced
bug that made PCHs non-functional. And, then, it appears that including
boost.test in PCH somehow upsets the compiler. Do things improve if you
take all boost.test headers out of bio-pch.h?

Thanks,
Volodya

P.S. Please don't ask new questions by replying to unrelated email,
I've nearly missed this one.

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