Opened 6 years ago

#12272 new Bugs

vertex_iterator dereference has odd return value

Reported by: ich.freak@… Owned by: Jeremiah Willcock
Milestone: To Be Determined Component: graph
Version: Boost 1.61.0 Severity: Problem
Keywords: Cc:

Description

graph_traits::vertex_iterator::operator* seems to not return Value& as it should. This not only differs from STL iterators but can and does easily cause segfaults.

Code highlighting: 

#include<list>
#include<boost/graph/adjacency_list.hpp>

typedef boost::adjacency_list<boost::vecS,boost::vecS> Graph;
typedef boost::graph_traits<Graph>::vertex_descriptor Vertex;
typedef boost::graph_traits<Graph>::vertex_iterator VIter;

const Vertex& deref(const VIter& it){
  return *it; // warning: returning reference to temporary [-Wreturn-local-addr]
}

const Vertex& deref(const std::list<Vertex>::iterator& it){
  return *it; // no warning, works fine
}


int main(){
  Graph g;
  Vertex u = boost::add_vertex(g);
  Vertex v = deref(boost::vertices(g).first);

  std::list<Vertex> vl(1, u);
  Vertex w = deref(vl.begin());

  return 0;
}

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