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

From: Bill Lear (rael_at_[hidden])
Date: 2006-06-15 08:53:00

On Thursday, June 15, 2006 at 09:56:00 (+0100) Russell Hind writes:
>...
>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?

I think what you mean is: does boost serialization guard against
forward incompatibility?  It does not: that's your job.  For any version
of your code, if you want to guard against forward incompatibility,
you simply need to do this:

#define TEST_CURRENT_VERSION 3 // or, something more sophisticated ..

class test {
    template <typename Archive>
    void serialize(Archive& ar, const unsigned int version) {
        // This code will refuse to try to load serialized archives >= 4
        if (version > CURRENT_VERSION) {
            throw forward_incompatibility_error("...");
        }
    }
};

BOOST_CLASS_VERSION(test, TEST_CURRENT_VERSION);

Of course, you could make an argument that boost should do this
automatically.:-)

Bill