Re: [Boost-users] [serialization] serialization of pointers toprimitive types?

From: Robert Ramey (ramey_at_[hidden])
Date: 2006-09-16 02:01:38

Serialization of pointers to primitive data types  is prohibited.  I'm 
pretty sure this is mentioned in the documentation. ( don't have the exact 
reference handy) - and it has been noted  a couple of times.  The reason is 
that doing this would result in ALL usages of that type being tracked - 
which is probably a heck of a lot more than the user had in mind.

The way to serialize pointer to primitives (serialization_level::prmitive) 
is to use BOOST_STRONG_TYPEDEF to define a new type and specify 
serialization function for it.  This won't work for std::string so you'll 
have to make a trivial derivation of std::string if you want to serialize a 
pointer to a std::string.

Robert Ramey

Joaquín Mª López Muñoz wrote:
> The following test program:
>
> #include <boost/archive/text_oarchive.hpp>
> #include <sstream>
>
> int main()
> {
>   int x=0;
>   int* const px=&x;
>   std::ostringstream oss;
>   boost::archive::text_oarchive oa(oss);
>   oa<<px;
>
>   return 0;
> }
>
> produces this error in MSVC++ 6.0:
>
> ...boost/serialization/access.hpp(109) : error C2228: left of
> '.serialize' must have
> class/struct/union type
>         ...boost/serialization/serialization.hpp(81) : see reference
> to function template
>         instantiation 'void __cdecl
> boost::serialization::access::serialize(
>          class boost::archive::text_oarchive &,int &,const unsigned
> int)'
>         being compiled
>
> and the following error in GCC 3.2:
>
> ...boost/serialization/access.hpp: In static member
>    function `static void
> boost::serialization::access::serialize(Archive&, T&,
>    unsigned int) [with Archive = boost::archive::text_oarchive, T =
> int]':
> ...
> ...boost/serialization/access.hpp:109: request for member
>    `serialize' in `t', which is of non-aggregate type `int'
>
> I've checked the same snippet against Boost 1.33.1, CVS HEAD and
> RC_1_34_0, using other primitive types like std::string, same problem
> always. Same problem also for the loading counterpart. When the
> pointed-to type is not primitive, though, everything works fine,
> regardless
> of whether the type has intrusive or non intrusive serialization
> support.
>
> I am sure I'm doing something really stupid here, but I've been
> banging my head against this several hours. Some clue greatly
> appreciated.
>
> Thank you,
>
> Joaquín Mª López Muñoz
> Telefónica, Investigación y Desarrollo