Re: [boost] [BGL] [variant] problem (and perhaps solution?) with strong_components.hpp and variant

Subject: Re: [boost] [BGL] [variant] problem (and perhaps solution?) with strong_components.hpp and variant
From: Nil Geisweiller (ngeiswei_at_[hidden])
Date: 2009-11-02 02:08:07

On Fri, Oct 30, 2009 at 8:46 AM, Jeremiah Willcock <jewillco_at_[hidden]> wrote:
> On Fri, 30 Oct 2009, Nil Geisweiller wrote:
>
>> It is weird, I tried with 2 settings
>>
>> Ubuntu 9.04, gcc-4.3.3, boost 1.40
>> Ubuntu 9.10, gcc-4.4.1, boost 1.40
>>
>> And I get the compiling errors:
>>
>> /usr/include/boost/property_map/property_map.hpp: In instantiation of
>> ‘boost::property_traits<int>’:
>> /usr/include/boost/graph/two_bit_color_map.hpp:46:   instantiated from
>> ‘boost::two_bit_color_map<int>’
>> /home/a-lin/Sources/test/test.cpp:10:   instantiated from here
>> /usr/include/boost/property_map/property_map.hpp:31: error: ‘int’ is
>> not a class, struct, or union type
>> /usr/include/boost/property_map/property_map.hpp:32: error: ‘int’ is
>> not a class, struct, or union type
>> /usr/include/boost/property_map/property_map.hpp:33: error: ‘int’ is
>> not a class, struct, or union type
>> /usr/include/boost/property_map/property_map.hpp:34: error: ‘int’ is
>> not a class, struct, or union type
>>
>> Has anyone experienced problem too?
>>
>> Thanks
>> Nil
>
> I'm surprised that this did not happen in earlier Boost versions.

yes it does not happen in boost 1.35. I've carefully compared some
files from the graph library between 1.35 and 1.40 and I don't see
anything suspect added in 1.40. So like you I am really surprised.

>  I think
> the problem is that two components are using exactly the same function name,
> and Boost.Graph's version (it's not in strong_components.hpp, just included
> from there) does not accept the template argument you are giving it.  As it
> appears that there is no member or other function to get the value out of a
> variant, it might be hard to avoid this error.  The version of get() in
> two_bit_color_map.hpp does not require any explicitly specified template
> arguments, but that is not the version you want anyway.

What do you think is the right way to fix that?

Thanks
Nil