[boost] Re: graph/subgraph: end iterator dereferenced

From: Guillaume Melquiond (guillaume.melquiond_at_[hidden])
Date: 2004-07-17 11:05:31

Le sam 17/07/2004 à 17:19, Doug Gregor a écrit :
> On Jul 17, 2004, at 4:15 AM, Guillaume Melquiond wrote:
> 
> > Hi,
> >
> > Line 189 of subgraph.hpp is:
> >
> >   return std::make_pair((*i).second, i != m_local_vertex.end());
> >
> > Consequently iterator i is dereferenced even when it is equal to
> > m_local_vertex.end(). So here comes a patch. When *i is not valid, the
> > patch simply returns u_global (the closest vertex_descriptor available
> > to the code), another value may make better sense (but since the value
> > is not supposed to be used).
> 
> You could use graph_traits<Graph>::null_vertex() to get a real "null" 
> vertex. Thanks for the patches! I'm hitting the road right now, but 
> I'll get to them tomorrow night if nobody gets there first.

I replaced u_global by null_vertex() and committed the first patch. I
also committed the second patch. However, the second one may require a
bit of review: the problem was obvious, but I'm not sure my solution
does what should be done (even if the subgraph.cpp test program is
happy).

Regards,

Guillaume