custom_graph_usage.cpp

struct UserDerivedType : 
  public IUserType
{
  // ...
};

void CreateCustomGraph(IProject& proj)
{
  // create a uniform graph; no customization at this point
  IUserGraphNode* first_node = proj.CreateUserGraph();
  
  for(int i=0; i<10; ++i)
  {
    // create custom data object
    UserDerivedType* new_custom_data = new UserDerivedType(...);
    // create a uniform node; make it point to custom data
    IUserGraphNode* new_node = first_node->AddNeighbor(new_custom_data));
  }
}

void UseCustomGraph(IUserGraphNode* some_node)
{
  // check whether it is a compatible node
  IUserType* node_data = some_node->GetLabel();
  UserDerivedType* node_checked_data;
  CHECK_INHERITANCE_SOMEHOW(node_data, node_checked_data); // how to to that? is static_cast safe?
  
  // use the node data
  //node_checked_data->...
}