glibmm n-ary tree example

#include <glibmm.h>
#include <iostream>

struct Vec2
{
    long x;
    long y;

    Vec2(long x, long y)
        : x(x), y(y)
    {}
};

struct Entity
{
    Vec2 position;
    Vec2 velocity;
    Vec2 acceleration;
    const char *name;

    Entity(const char *name)
        : position(0, 0),
          velocity(0, 0),
          acceleration(0, 0),
          name(name)
    {}

    ~Entity()
    {
        std::cout << "Entity " << name << " says goodbye\n";
    }
};

typedef Glib::NodeTree<Entity> ENode;

bool travFun(ENode &node)
{
    std::cout << "Traversing node: " << node.data().name << "\n";

    return false;
}

int main(int, char**)
{
    Entity root("Root");
    root.position = Vec2(10, 20);

    ENode tree(root);

    tree.append_data("child");

    tree.append_data("child2");

    tree.traverse(sigc::ptr_fun(&travFun), Glib::TRAVERSE_POST_ORDER);

    return 0;
}