[boost] [Serialization] Question about "Back versionning"

Subject: [boost] [Serialization] Question about "Back versionning"
From: Vincent Thomas (v.thomas_at_[hidden])
Date: 2009-10-02 17:14:11

Hi,

    During some testing of boost::serialization features, I tried to do
this :
    Let's say we have a class X, the current version for this class is 5
(BOOST_CLASS_VERSION(X, 5)). Serialize in class X is split into
save/load.What I'd like to do now, is save an object of type X  at
version 3 to make the object loadable by an older version of my
software. that is get ""<X class_id="0" tracking_level="0" version="3">"
in my resulting file instead of "<X class_id="0" tracking_level="0"
version="5">".

    I've gone through the documentation of boost::serialization and I
found only one thing. A TODO speaking about "Back versionning". It's not
clear for me if this part speaks about the archive (like xml_oarchive,
xml_iarchive, ...) or the object I can serialize, in other words does it
concern this line "<boost_serialization
signature="serialization::archive" version="5">" or a line like this one
"<test class_id="0" tracking_level="0" version="2">" in a resulting file
? Maybe it concerns both but that I don't know.

    So apparently If I understand the documentation correctly I can't do
what I describe above at the moment. Does anyone know if it's going to
be implemented soon, or if I can be of any help ?

Vincent