// compile with:
// g++ -std=c++11 -Wall -Wextra -pedantic -Wno-ignored-qualifiers -g3 -O0 -I${BOOST_INCLUDE} unlink-header.cpp -o unlink-header

#include <iostream>
#include <cassert>
#include <vector>
#include <boost/intrusive/list.hpp>
#include <boost/intrusive/trivial_value_traits.hpp>

namespace bi = boost::intrusive;

struct A
{
    A(int val = 42) 
        : val_(val), prev_(nullptr), next_(nullptr)
    {
        std::cout << "constructing element with val_=" << val << "\n";
    }
    ~A()
    {
        std::cout << "destroying element with val_=" << val_ << "\n";
        assert(is_unlinked());
    }
    bool is_unlinked() const { return not(prev_ or next_); }
    int val_;
    A* prev_;
    A* next_;
};

struct Node_Traits
{
   typedef A node;
   typedef A* node_ptr;
   typedef const A* const_node_ptr;
   static node *get_next(const node *n)            { return n->next_; }
   static void set_next(node *n, node *next)       { n->next_ = next; }
   static node *get_previous(const node *n)        { return n->prev_; }
   static void set_previous(node *n, node *prev)   { n->prev_ = prev; }
};

typedef bi::trivial_value_traits< Node_Traits, bi::safe_link > Value_Traits;
typedef bi::list< A, bi::value_traits< Value_Traits > > list_t;

int main()
{
    std::cout << "constructing vector\n";
    std::vector< A > a_cont;
    a_cont.reserve(3);
    a_cont.emplace_back(0);
    a_cont.emplace_back(1);
    a_cont.emplace_back(2);
    {
        std::cout << "constructing list\n";
        list_t l(a_cont.begin(), a_cont.end());
        std::cout << "clearing list\n";
        l.clear();
        std::cout << "clearing vector\n";
        a_cont.clear();
        std::cout << "destroying list\n";
    }
    std::cout << "done\n"; // never reached
}