////////////////////////////////////////
// test2 -- uses boost::enable_if<>
// and boost::is_convertible<>
////////////////////////////////////////

#include <iostream>
#include <boost/utility/enable_if.hpp>
#include <boost/type_traits/is_convertible.hpp>

using namespace std;

struct Foo
{
  Foo() {}
  
  Foo(Foo const & f)
  {
    cout << "Copy Constructor." << endl;
  }

  template <typename T>
  Foo(T const & src,
      typename boost::enable_if<
      boost::is_convertible<T,Foo>, void >::type * dummy = 0)
  {
    cout << "Convertible." << endl;
  }

  template <typename T>
  Foo(T const & src,
      typename boost::disable_if<
      boost::is_convertible<T,Foo>, void >::type * dummy = 0)
  {
    cout << "Not Convertible." << endl;
  }

};

int main()
{
   Foo f;
   Foo f2(f);
   Foo f3(1);

   return 0;
};