Thanks a lot, even though I read half of the BGL book I didnt get this difference. I cant say Im good with techniques like that. Best, Tasos

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Message: 1 Date: Thu, 31 Jan 2013 11:12:29 -0500 (EST) From: Jeremiah Willcock To: boost-users@lists.boost.org Subject: Re: [Boost-users] [Graph] visitor dijkstra_shortest_paths Message-ID: Content-Type: text/plain; charset="iso-8859-1"; Format="flowed"

On Thu, 31 Jan 2013, The Maschine wrote:

...

Hi all,

Can someone explain me why I get an error with the first one and not the

second?

...

1)

(error)?boost::dijkstra_shortest_paths(m_ugraph,*vertex_iterator_begin,? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?

...

?boost::distance_map(boost::make_iterator_property_map(dist_map.begin(), boost::get(boost::vertex_index, m_ugraph))),

boost::visitor(dijkstra_vis( *vertex_iterator_begin, superStorage ) ));

The syntax for named parameters in Boost.Graph requires periods, so all named arguments show up as a single argument to C++.

...

2) (good)?boost::dijkstra_shortest_paths(m_ugraph,*vertex_iterator_begin,? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?boost::distance_map(boost::make_iterator_property_map(dist_map.begin(), boost::get(boost::vertex_index, m_ugraph))).visitor(dijkstra_vis( *vertex_iterator_begin, superStorage ))?);

Why I need to "." the visitor on the distance_map?

That's how it was implemented (before Boost.Parameter or variadic templates existed).

...

BFS is ok with it:

(good) boost::breadth_first_search(m_ugraph, *vertex_iterator_begin ,

boost::visitor(bfs_vis(

...

*vertex_iterator_begin, superStorage ) ));

You only have one named argument there; if you had more, you would need to use a period between those as well.

-- Jeremiah Willcock