Re: [Boost-users] Removing a vertex and adding another one with the same id causes segmentation fault?

Subject: Re: [Boost-users] Removing a vertex and adding another one with the same id causes segmentation fault?
From: Alper Aydemir (alperaydemir_at_[hidden])
Date: 2011-12-14 12:50:21

The formatting went bad with the previous email. Sorry about that.
Here it is once again.

Hello,

I'm using a labeled graph

typedef boost::labeled_graph<boost::adjacency_list<boost::listS,
boost::listS, boost::undirectedS, Room, RoomEdge>,std::string>
MyGraph;

which lets me access vertices with string ids.

I add a vertex and set it's relevant fields this way:

MyVertex u = boost::add_vertex(id, g);
g[id].category = category; //crashes here
g[id].vertex_id = id;

Here id is an std::string. And remove them like so:

// First we remove all edges from this vertex
BGL_FORALL_VERTICES(v, g, MyGraph){
    if (QString(g.graph()[v].vertex_id.c_str()).compare(roomIdToBeRemoved)
== 0){
        ve = v;
        BGL_FORALL_OUTEDGES(v, e, g, MyGraph) {
            ev.push_back(e);
        }
    }
}

foreach(MyEdge e, ev){
    remove_edge(e,g);
}

// Then we remove the vertex itself
remove_vertex(roomIdToBeRemoved.toStdString().c_str(),g);

This so far seems to work. The trouble is, if I want to add a removed
vertex once again with the same id, I get the following:

Exception Type:  EXC_BAD_ACCESS (SIGSEGV)
while setting the fields of the newly added vertex (above commented
"crashes here").

What might be the reason? I'm using boost functions for removing/adding things.