Re: [Boost-users] [serialization-1.32.0] de-serializing newer versions that the application can deal with

From: Robert Ramey (ramey_at_[hidden])
Date: 2006-06-15 10:50:41

Russell Hind wrote:
> We have system data written out to an XML archive and being
> de-serialized at application startup.
>
> One object type in the archive we written at version 1 by a newer
> version of the application.  We then ran an older version of the
> software which only understood version 0 of the object.
>
> Does serialization not check the 'BOOST_CLASS_VERSION' of an object
> before attempting to de-serialize it?
>
> If not, how can we access the 'BOOST_CLASS_VERSION' in a serialization
> member function?  I'm looking to do something like this: (this code is
> just written now so probably is incorrect but hopefully gives the
>  idea). How do we check 'version_of_T' below which should correspond
> to the BOOST_CLASS_VERSION for T?
>

boost::serialization::version<T>::value should contain the version of the 
type being used by program.  If you want old programs to check for newer 
versions try

void serialize(Archive &ar, T & t, const unsigned version){
    if(version > boost::serialization::version<T>::value)
        throw exception(....)

It never occured to me to build this into the serialization library itself, 
Now that it has been mentioned, it seems like a worthy idea.  I'll consider 
it.

Robert Ramey