Graph library iterator const-ness

From: Rob Smallshire (robert_at_[hidden])
Date: 2001-07-19 05:20:51

I'm using the Boost graph library at the moment, and just getting the 
hang of the vast number of iterator types I have to play with.

With the boost::graph_traits<>::adjacency_iterator(which is 
dereferencable to a vertex descriptor), what are the const semantics 
(intended and/or implemented) of this iterator ?

Presumably, I can't change the neighbours of a vertex by fiddling 
with what the adjacency_iterators returned by adjacent_vertices() are 
pointing to ?  So is it behaving as a 'const_adjacency_iterator' even 
though it doesn't have this name ?

This is important to me because my class (which contains a Boost 
graph), needs to be able to return a list of neighbours for a given 
vertex. I could copy the list of neighbours into a container and 
return a reference to the container, but it would be nicer to just 
return the adjacency_iterators to the client code for my class, but I 
don't want the client code to be able to modify the data in my class, 
so the iterators should be the equivalent of const_iterators.

Thoughts/comments ?

Rob Smallshire