Re: [Boost-users] [serialization] [units] class_id and class_name to describe quantity dimension in serilization archive

Subject: Re: [Boost-users] [serialization] [units] class_id and class_name to describe quantity dimension in serilization archive
From: alfC (alfredo.correa_at_[hidden])
Date: 2011-09-24 02:40:04

Hi, 

On Friday, September 23, 2011 7:10:48 PM UTC-7, Bob Dean wrote:
>
> The BOOST_SERIALIZATION_NVP macro is shorthand for the 
> boost::serialization::make_nvp(string name,object) template function. 
> Easiest thing would be to call it directly:
>
> oa << boost::serialization::make_nvp("quantity_si_length",q);
>
sorry if my question was not understood. It is fine (and necessary to have 
the element named "q"), what I want is that in the class description some 
information about the type itself, instead of class_id = 0. Such to produce:

<*q* class_id="0" class_name = "*quantity_si_length*" tracking_level="1" 
version="0" object_id="_0">
    <value>5</value>
</*q*>

note that I am fine with the "q" name (either using BOOST_..._NV or 
make_nvp), I want some (automatic) description of the type not the element.

Thank you,
Alfredo

On Sep 23, 2011, at 8:50 PM, alfC <alfredo..._at_[hidden]> wrote:
>
> > Hi, 
> > I am serializing a bunch of object that contains boost.units quantities. 
> Boost.Units provides serialization for quantities already.
> > By default, the output file looks ok but I would like to add a class name 
> to the object description.
> > 
> > Current, serializing quantity<si::length> q produces:
> > 
> > <q class_id="0" tracking_level="1" version="0" object_id="_0">
> >     <value>5</value>
> > </q>
> > 
> > Which doesn't give any information about the quantity at hand, not even 
> for the human reading it. So, I tried to use BOOST_CLASS_EXPORT_GUID to 
> register a name for the serialized class, but it is ignored.  Ideally I 
> would like to have something like this, with a class_name description for 
> example:
> > 
> > <q class_id="0" class_name = "quantity_si_length" tracking_level="1" 
> version="0" object_id="_0">
> >     <value>5</value>
> > </q>
> > 
> > Is something like this possible? Below is the working code:
> > 
> > #include <fstream>
> > #include <boost/serialization/export.hpp>
> > #include <boost/archive/text_oarchive.hpp>
> > #include <boost/archive/xml_oarchive.hpp>
> > #include <boost/units/systems/si/io.hpp>
> > using namespace boost::units;
> > BOOST_CLASS_EXPORT_GUID(quantity<si::length>, "quantity_si_length") 
> //ignored
> > 
> > int main(int argc, char *argv[]) {
> >     std::ofstream ofs("filename.xml");
> >     boost::archive::xml_oarchive oa(ofs);
> > 
> >     quantity<si::length> q = 5.*si::meter;
> > 
> >     oa << BOOST_SERIALIZATION_NVP(q);
> > 
> >     return 0;
> > }
> > 
> > _______________________________________________
> > Boost-users mailing list
> > Boost..._at_[hidden]
> > http://lists.boost.org/mailman/listinfo.cgi/boost-users
> _______________________________________________
> Boost-users mailing list
> Boost..._at_[hidden]
> http://lists.boost.org/mailman/listinfo.cgi/boost-users
>
>