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Subject: Re: [boost] [parameter] Boost.Graph program not responding at run-time
From: Lorenzo Caminiti (lorcaminiti_at_[hidden])
Date: 2011-12-03 15:11:44

On Sat, Dec 3, 2011 at 2:28 PM, Jeremiah Willcock <jewillco_at_[hidden]> wrote:
> On Sat, 3 Dec 2011, Lorenzo Caminiti wrote:
>> If I move the call to boost::depth_first_search into a template
>> depth_first_search_impl and out of the Boost.Parameter function body,
>> the code compiles (both MSVC and GCC with latest Boost from trunk) but
>> the executable runs forever and prints nothing to cout... What am I
>> doing wrong?
> I tried your code with GCC 4.6.0 and it worked just fine as you pasted it
> below.  I get:
> order of discovery: u v y x w z
> order of finish: x y v u z w
> as the result.  You are returning an invalid pointer from
> default_color_map(), though; &colors[0] becomes invalid when colors is
> destroyed at the end of the function.

Oops... thanks, that was actually the issue, after I fixed the invalid
pointer the code runs fine.

BTW, what's the best way to generate a default_color_map for
Boost.Graph like the one below?

template< typename Size, typename IndexMap >
boost::iterator_property_map<boost::default_color_type*, IndexMap,
        boost::default_color_type, boost::default_color_type&>
default_color_map ( Size const& num_vertices, IndexMap const& index_map )
    std::vector<boost::default_color_type> colors(num_vertices);
    return &colors[0]; // *** Error: invalid ptr... ***


        (graph, *(is_incidence_and_vertex_list_graph<boost::mpl::_>))
        (visitor, *, boost::dfs_visitor<>())
                *(is_integral_property_map_of_key< boost::mpl::_,
                        vertex_descriptor<tag::graph::_> >),
                boost::get(boost::vertex_index, graph))
                *(is_property_map_of_key< boost::mpl::_,
                        vertex_descriptor<tag::graph::_> >),
index_map)) // *** Note: color map used here ***
) {
    return depth_first_search_impl<graph_type, visitor_type, root_vertex_type,
            index_map_type, color_map_type>(graph, visitor, root_vertex,
            index_map, color_map);


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