Ben Artin wrote:

I am using boost 1.32. When I serialize a string, no metadata is written, as implementation_level<string> is set to primitive_type in serialization/string.hpp. However, when I serialize a vector<string>, I end up with metadata, because implementation_level<vector<string> > is not set anywhere and therefore defaults to object_class_info.

Every other primitive type appears to be covered by BOOST_SERIALIZATION_COLLECTION_TRAITS and therefore implementation_level<vector<T> > is object_serializable for every other primitive type.

I suppose I didn't think about this when I did it. Setting implementation_level to object_serializable rather than the default it really just a tiny optimization. If I had thought about it more I would have added vector<string> to the list. For now I'm not inclined to change it for fear of creating compatibility problems with existing archives - though "downgrading" should work fine - I just don't want to risk it now.

My question: is this an omission; that is, should implementation_level<vector<string> > be object_serializable? (And similarly for other collections of strings.)

I suppose they should have been. Robert Ramey