Re: [Boost-users] [serialization] serializing a pointer withoutcausingobject tracking

Subject: Re: [Boost-users] [serialization] serializing a pointer withoutcausingobject tracking
From: Robert Ramey (ramey_at_[hidden])
Date: 2013-04-01 19:51:06

Robert Ramey wrote:
> Stefan Strasser wrote:
>> Am 30.03.2013 19:03, schrieb Robert Ramey:
>>>> is there a solution to this? is there a serialization wrapper that
>>>> says "don't track this type just because of this pointer"?
>>>
>>> so you want "don't track this particular save - but leave others as
>>> normal" Try something like
>>>
>>> class A ....
>>>
>>> class UntrackedA : public A {
>>> ...
>>> };
>>>
>>> BOOST_SERIALIZATION_TRACK(UntrackedA, track_never);
>>
>> interesting idea. does this eventually track the object if the base
>> class of UntrackedA is track_selectively and saved through a pointer
>> anywhere else?
>>
>> for example, an object graph that stores a pointer to its own root
>> (through intermediaries in practice):
>>
>> class A{ //tracking level: selectively
>>   void serialize(...){ ar & a; }
>>   A *a; //==this
>> };
>>
>> class UntrackedA : A{ //tracking level: never
>>   void serialize(...){ ar & base_object<A>(*this); }
>> }
>>
>> void save(UntrackedA *a){ ar << a; }
>>
>> is "a" serialized twice, or tracked because of track_selectively and
>> the pointer serialization in A::serialize?
>
> lol - I didn't think about this when I responded though I'm sure I
> did it when I made the code.  I'm going to speculate since it's
> easier than doing any work.
>
> class UntrackedA : public A {
>    // instead of this:
>    void serialize(Archive & ar, unsigned int file_version){
>        boost::serialization:base_object<A>(*this);
>    }
>    // consider this
>    void serialize(Archive & ar, unsigned int file_version){
>        ar & m_a; // where m_a is a member of a
>        ar & m_b; // other member of a etc ...
>    }
>   ...
>

better yet try this:

class UntrackedA : public A {
};

just use the base class implementation of serialize function via inheritance

Robert Ramey

>
> Robert Ramey