[Boost-users] [serialization] Private default constructors

Subject: [Boost-users] [serialization] Private default constructors
From: Robert Dailey (rcdailey_at_[hidden])
Date: 2009-04-02 20:11:11

I have a class that can be constructed statically in code, or constructed by
data (this is where boost::serialization comes in).

For example:

class foo
{
public:
    foo() {}
    foo( std::string text )
        : m_text( text )
    {}

private:
    template< class Archive >
    void serialize( Archive& archive, unsigned int version )
    {
        archive & m_text;
    }

    std::string m_text;

    friend class boost::serialization::access;
};

There is one problem with this, though. It is possible for a user of this
class to create a "foo" with the default constructor, thus enabling them to
have "zombie" objects. The only thing I want using the default constructor
is boost::serialization, not the user. Is there a way I can make the default
constructor private and still have boost::serialization access it? Keep in
mind that this must work polymorphically too.