Re: [Boost-users] [repost][serialization] version handling in {save|load}_construct_data

Subject: Re: [Boost-users] [repost][serialization] version handling in {save|load}_construct_data
From: OvermindDL1 (overminddl1_at_[hidden])
Date: 2010-01-09 20:01:59

On Sat, Jan 9, 2010 at 11:19 AM, JOAQUIN M. LOPEZ MUÑOZ <joaquin_at_[hidden]> wrote:
> Hello, allow me to repost this message from a couple of
> weeks ago:
>
> I've taken a look at how the version number is dealt with
> in Boost.Serialization collection serialization code:
>
> * The relevant code at saving time is:
>
> Â Â Â  if(3 < ar.get_library_version()){
> Â Â Â Â Â Â Â  const unsigned int item_version = version<
> Â Â Â Â Â Â Â Â Â Â Â  BOOST_DEDUCED_TYPENAME Container::value_type
> Â Â Â Â Â Â Â  >::value;
> Â Â Â Â Â Â Â  ar << BOOST_SERIALIZATION_NVP(item_version);
> Â Â Â  }
>
> * At loading time, the equivalent code is:
> Â Â Â  unsigned int item_version;
> Â Â Â  ar >> BOOST_SERIALIZATION_NVP(count);
> Â Â Â  if(3 < ar.get_library_version())
> Â Â Â Â Â Â Â  ar >> BOOST_SERIALIZATION_NVP(item_version);
> Â Â Â  else
> Â Â Â Â Â Â Â  item_version = 0;
> Can someone (aka Robert :-) ) shed some light on this bit?
> Why the version number has to be given such manual processing
> when this is not needed if, for instance, serializating
> values via the simple ar&value?
> I'm trying to do the equivalent thing in Boost.MultiIndex.
>
> Thank you,
>
> Joaquín M López Muñoz
> Telefónica, Investigación y Desarrollo

For note, your email was a big black blob on my black background.  If
you are going to specify a text color (black in your case), make sure
you specify a background color (transparent in your case, which on my
black background makes your text invisible).  Better to just send as
pure text anyway.