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Borland C++Builder lost+found #6 See Also:  C++Builder Papers and Columns

Friends near and far
One of the gotcha's in the new C++ standard is the lookup of friend functions. The 'Standard' stipulates that friends must be in the same namespace as the class that wants to befriend either a clas or a function. This may lead to some trouble. Consider:

namespace MyNameSpace
{
  class Foo
  {
    public:
      Foo();
    virtual ~Foo();
      friend ostream& operator<<(ostream& ostr, const Foo& object);
    };
  };

namespace MyFoo
{
  class Foo
  {
  public:
    Foo();
    virtual ~Foo();

  friend std::ostream& operator<<(std::ostream& ostr, const Foo& object);
  protected:
    virtual void PrintOn(std::ostream& ostr) const;
  };
};

MyFoo::Foo::Foo()
{}

MyFoo::Foo::~Foo()
{}

std::ostream& MyFoo::operator<<(std::ostream& ostr, const MyFoo::Foo& object)
{
  ostr << object << std::endl;
  return ostr;
}

void MyFoo::Foo::PrintOn(std::ostream& ostr) const
{
  ostr << "Foo";
}