Re: [boost] [serialization] Regressions?

From: David Abrahams (dave_at_[hidden])
Date: 2005-06-24 08:24:47

Vladimir Prus <ghost_at_[hidden]> writes:

>    > 
>    > Its very easy to write
>    > for(...{
>    >     X x = *it; // create a copy of
>    >     ar << x
>    > }
>    > 
>    > all the x's are at the same address so if they happen to be tracked   
>    > because 
>    > a pointer to some X in serialized somewhere in the program, then the
>    > subsequent copies would be supprsed by tracking. 
>
> What does "the subsequence copies would be supressed by tracking"? Are you
> saing that only one 'X' will be stored in archive? 

Yes, if (as is highly likely) the x happens to have the same address
in each iteration of the loop.  To reconstruct object graphs correctly
(that's what tracking is for), you need to do it that way.

> And what will happen duing deserialization. Will you load just one
> 'X' object, and then for each iteration of deserialization loop,
> make a copy of it?

Surely it depends what the deserialization loop looks like, but the
serialization library itself won't make any copies: it will return a
reference or pointer to that same object each time.

-- 
Dave Abrahams
Boost Consulting
www.boost-consulting.com