On Mon, 19 Apr 2004 09:52:13 -0700, Robert Ramey wrote

Jeff Garland wrote:

...

I believe that Matthew has now demonstrated that archive extension is possible, which I believe is one of the major changes from the first review. That said, any documentation of this process would clearly be a plus. In a typical proprietary archives writing of the version and type numbers will need to be shut off. So I can imagine documenting these sorts of issues.

As it turns out, type id, and object id are really required only for pointers and version is in fact optional.

It would be possible to make an archive which:

a) trapped (BOOST_STATIC_ASSERT) attempts to serialize a pointer b) trapped attempt to save/load object id and class id c) implemented null serialization of version numbers and trapped attempts to use version number != 0

This would work only on serializations that had implementation attributes of no versioning, and no object tracking. If used on other types, it would trap at compiler time.

Excellent -- that's a clear advantage of this design over the typical virtual function based approach.

I believe that you would have what you wanted. In general, the part of the library which saves/loads the preamble is invoked only for pointers. An easy way to check this is to generate XML archive and find that there are not attributes for this types.

I suspected that this was the case -- nice to know the details :-) Jeff