The recommended way is to throw an exception from within the visitor: http://www.boost.org/doc/libs/1_59_0/libs/graph/doc/faq.html e.g. create a termination struct: struct all_done_signal{}; and then throw it in the visitor: throw all_done_signal{}; and wrap the algorithm in a try-catch block: try { graph_algorithm(my_visitor); } catch(const all_done_signal&) { /* early termination */ } Now, I don't understand why you need a depth-first-search for enumerating all vertices with zero input edges. What about: boost::for_each(vertices(graph), check_no_in_edges); with a check_no_in_edges lambda that counts the each vertex' in_edges? (Note: instead of for_each you might want to use accumulate, or similar) Cheers, Daniel J H On 11/25/2015 01:13 AM, Isaac Lascasas wrote:

Hello I want to enumerate all vertices with zero input edge count in a graph, I am using DFS right now:

struct vertex_visitor : public boost::default_dfs_visitor { std::vector Output;

void discover_vertex(vertex_t v, graph_t const& g) { graph_t::in_edge_iterator edgeIt, edgeEnd; tie(edgeIt, edgeEnd) = boost::in_edges(v, g); if (edgeIt==edgeEnd) Output.push_back(v); } };

vertex_visitor vis; boost::depth_first_search(g, boost::visitor(v));

However I don't know how to cleanly stop execution after depth 0 inside my visitor and I can't figure out a better way to archieve this. Since I am fairly new to boost graph I supose that I'm missing something.

Thanks.

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