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

Subject: Re: [Boost-users] 'Multiply defined' errors in Boost 1.38.
From: Dyer, Nigel (N.P.Dyer_at_[hidden])
Date: 2009-02-24 03:31:40

Hi Volodya

Apologies...  I now see that the boost documentation says that the gcc
compiler prior to 4.2 does not support anonymous namespaces in
precompiled headers.  I am using the Darwin compiler that comes with the
Apple Servers, and had rather assumed it was based on a current gcc, but
I see that it is still based on gcc 4.0.1.  The simple workaround is to
not use precompiled headers.  I have also showed that the problem can be
fixed by removing the boost libraries from the pre-compiled headers that
use anonymous namespaces, either directly or indirectly.

Your other comments were very useful, although I am still looking into
why the <use>/boost/filesystem//boost_filesystem is needed in the pch
definition on the mac, when it does not appear to be necessary on other
platforms.

I have found a number of other problems mainly relating to dependency
checking that occur on the mac and not on the other platform, so I am
going to install a later version of gcc, which will hopefully bring the
mac server platform in line with the linux and windows platforms where
everything works just fine.

Nigel

-----Original Message-----
From: boost-users-bounces_at_[hidden]
[mailto:boost-users-bounces_at_[hidden]] On Behalf Of Vladimir Prus
Sent: 22 February 2009 16:54
To: boost-users_at_[hidden]
Subject: Re: [Boost-users] 'Multiply defined' errors in Boost 1.38.

Dyer, Nigel wrote:

> 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.

So, you have a workaround?

> 
> 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.

Well, you can add <use>/boost/filesystem//boost_filesystem to the
requirements
of our pch target so that the PCH is built withe the same defines as the
your executable.

> I assume that this 
> means that precompiled headers are incompatible with dynamic link
> builds, although this does not appear to be mentioned.

No, this means that PCH should be built with *exactly* the same compiler
options, including defines.

> 
> 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

There's no such variant as 'static', FWIW. There's <link>static

- Volodya

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