Re: [Boost-users] [Boost 1.44][BGL] Compiling error with MinGW

Subject: Re: [Boost-users] [Boost 1.44][BGL] Compiling error with MinGW
From: Jeremiah Willcock (jewillco_at_[hidden])
Date: 2010-11-09 11:41:10

On Tue, 9 Nov 2010, Florian.PONROY_at_[hidden] wrote:

> 
> Hi folks,
> 
> My C++ Windows/Linux project used to compile properly using the following items:
>
>  *  Boost 1.33.1, using BGL, Serialization, Thread ;
>  *  GNU g++ 4.1.2 under Linux ;
>  *  MinGW 3.4.5 under Linux (cross-compiling).
> 
> I recently updated my Boost distribution to version 1.44. Unfortunately, I now have the following BGL/linking error
> compiling with MinGW :
> 
> /path/to/liblocd_topology_manager.a(locTopology.o):locTopology.cpp:(.rdata$_ZZN5boost3putINS_26vec_adj_list_vertex_
> id_mapINS_8propertyINS_13vertex_root_tEiNS_11no_propertyEEEjEEEEvRKNS_17two_bit_color_mapIT_EENS_15property_traitsI
> S8_E8key_typeENS_18two_bit_color_typeEE17elements_per_char+0x0): multiple definition of `_elements_per_char'
> 
> /path/to/liblocd_topology_manager.a(locTopology.o):locTopology.cpp:(.rdata$_ZZN5boost3putINS_26vec_adj_list_vertex_
> id_mapINS_8propertyINS_13vertex_root_tEiNS_11no_propertyEEEjEEEEvRKNS_17two_bit_color_mapIT_EENS_15property_traitsI
> S8_E8key_typeENS_18two_bit_color_typeEE17elements_per_char+0x0): first defined here
> 
> I've checked the //www.boost.org/doc/libs/1_44_0/libs/graph/doc/trouble_shooting.html webpage, but I haven't seen
> any answer related to my problem.
> 
> For sure, the MinGW compiler version we use is pretty old. Since updating it would be very cumbersome in our case, I
> would like to be sure it's actually a compiler issue.
> 
> Thanks in advance for your advice.

This looks like a compiler issue -- elements_per_char is a static constant 
(using BOOST_STATIC_CONSTANT), so it should not have any linkage problems 
like what you're having.  I'm not an expert on MinGW, so I don't know the 
cause of the issue; it looks similar to 
<URL:http://efreedom.com/Question/1-1974077/Vector-Multiple-Definition-Link-Errors>, 
though.

-- Jeremiah Willcock