Re: [Boost-users] Serialization: crash at launch of program(duetoboost::serialization::base_object)

From: Robert Ramey (ramey_at_[hidden])
Date: 2006-04-06 11:19:57

I would be wiling to look at a small example which demonstrates the problem.

Robert Ramey

RIVASSEAU Jean Noel wrote:
> I have tried to use versioning. Exact same problem.
>
> More explanations: if I use the version facility,  and at load I
> switch the boost::serialization::base_object<MyBaseClass> depending
> on the version, the same crash will happen.
>
> Eg: this code:
>
> if (version == 0)
> {
> boost::serialization::base_object<MyBaseClass_1>
> }
> Else
> {
> boost::serialization::base_object<MyBaseClass_2>
> }
>
> Will cause the same crash.
>
> So, could you look at the code, because currently there is no way to
> change the base class of an object appearing in serialized archives,
> if you want to be able to read old archives.
>
> It seems like there is a bug, if the base_object is used several
> times with different classes, the crash will appear.
>
> Thanks
>
> Jean-Noël
>
>
> -----Message d'origine-----
> De : boost-users-bounces_at_[hidden]
> [mailto:boost-users-bounces_at_[hidden]] De la part de Robert
> Ramey
> Envoyé : mercredi 5 avril 2006 17:15
> À : boost-users_at_[hidden]
> Objet : Re: [Boost-users] Serialization: crash at launch of program
> (duetoboost::serialization::base_object)
>
> The "version" facility is provided for maintaining the ability to
> read old
> archives.  It doesn't sound like you're using this and its sounds
> like you
> should be.
>
> Robert Ramey
>
>
> "RIVASSEAU Jean Noel" <JN.RIVASSEAU_at_[hidden]> wrote in message
> news:87F60F7FA02FF749AFB02BD9FCAA6B0401074928_at_naserv31.nanterre.oberthurcs.com...
> Hello,
>
> My program crashes at launch (not even a exit(0) as the first line of
> main(int argc, char *argv[]) will stop it from crashing), due to the
> BSL.
>
> What I am trying to do is: I have a class, whose serialization is
> split (eg,
> save and load functions are provided, and they are different). Now
> this
> class had a parent class, so I used to call
> boost::serialization::base_object<MObject>() on the base class
> MObject.
>
> However I want to change the parent of my class to a different class.
> I also
> want to update my old archives, so I decided to leave the load
> function of
> my class untouched, while I would change the save function, to update
> the
> call to base_object to the new parent class (not MObject anymore). I
> thought
> it would work, since it would load the old archive using the same
> method,
> but save it using the new, so I would have ran only one time the
> program and
> the archive would be updated (then, of course, before running it
> again I
> would have to recompile it one more time with the correct changes to
> the
> load function).
>
> But it does not work as expected, since it seems the BSL does not
> like the
> fact that save and load functions calls to
> boost::serialization::base_object
> do not specify the same base class. It does not complain at compile
> time but
> crashes at run time before even entering main and certainly before
> loading
> any archive. The crash is due to a NULL pointer, I have tried to
> debug with
> gdb but the crash apparently occurs on the _libkernel32_a_iname () so
> I do
> not not know where it is (too low level for me).
>
> Robert, do you have an idea what is going on? I suspect a bug -
> however if
> it is "normal" behaviour (I think it should then throw an exception
> rather
> than crash),
>
> ***
> Tell that to the author of _libkernel32_a_iname ()
>
> do you have an idea how could I update my archives? I need to change
> the
> parent of this class, but need to be able to read my old archives -
> and
> changing them "by hand" by looking into the XML archive code is tool
> hard.
>
> Thank you, regards
>
> Jean-Noël Rivasseau
>
>
>
> _______________________________________________
> Boost-users mailing list
> Boost-users_at_[hidden]
> http://lists.boost.org/mailman/listinfo.cgi/boost-users =