At 04:13 AM 11/8/2004, Francis ANDRE wrote:
Hi
In order to serialize a derivative class of boost/filesystem/path, one cannot access the base class member m_path without changing its visibility from private to protected:
I would suggest to change the visibility of this m_path member from private: to protected, or to add an implicit definition of the serialize method into the class boost::filesystem::path.
#include <boost/filesystem/path.hpp> namespace boost { namespace serialization { class access; }}
class OSD : public boost::filesystem::path { private: friend class boost::serialization::access; friend std::ostream & operator<<(std::ostream &os, const OSD&); template<class Archive> void serialize(Archive &ar, const unsigned int version) { ar & m_path; } };
I don't particularly like either of those solutions. * Changing m_path from private to protected effectively adds m_path to the class interface, yet m_path is an implementation artifact that might not be present at all in a different implementation. * Adding a dependency to the serialization library isn't a good idea either. No matter how nice boost.serialization is, some boost.filesystem users will not wish to use it, and will not want the dependency. Class path already has a member, path::string(), which in the current implementation returns a reference to m_path, and in any implementation must return the equivalent of a const reference to m_path. Going the other way, the append function can be used to import a serialized string. I'm not familiar with how boost.serialization works, but wouldn't you be better off to use those already public functions for serialization? If not, I'm willing to make m_path protected, but would like to explore other approaches to the serialization problem first. Thanks, --Beman