[C++-sig] Boost Python loss of values

[Jay Riley]

Self is indeed a PyObject* 

this is a bit confusing

> Date: Fri, 26 Aug 2011 13:00:11 -0700
> From: talljimbo at gmail.com
> To: cplusplus-sig at python.org
> Subject: Re: [C++-sig] Boost Python loss of values
> 
> On 08/26/2011 08:27 AM, Jay Riley wrote:
> > Hi Jim,
> >
> > Thanks for the suggestion, unfortunately it didn't work. It really feels
> > like it's making a copy for some reason as once I return to the
> >
> > int AttackWrapper::CalculateDamage(const
> > std::vector<Game::Battles::BattleCharacter*>& users,
> > Game::Battles::BattleCharacter* target, const
> > std::vector<Actions::ActionTarget>& targets, Game::Battles::BattleField
> > *field)
> > {
> > return call_method<int>(self, "CalculateDamage", users, ptr(target),
> > targets, ptr(field));
> > }
> >
> > function, the value are back to their expected value. Slicing wouldn't
> > be a problem here would it, since Hit is a member of the base class anyways?
> >
> 
> Yes, that's right.  What exactly is "self", above?  I assume it's a data 
> member of AttackWrapper of type PyObject *, which shouldn't produce a 
> copy, but if it's something else, well, that could be a factor.
> 
> Jim
> 
> 
> 
> >  > Date: Thu, 25 Aug 2011 13:18:04 -0700
> >  > From: talljimbo at gmail.com
> >  > To: cplusplus-sig at python.org
> >  > CC: super24bitsound at hotmail.com
> >  > Subject: Re: [C++-sig] Boost Python loss of values
> >  >
> >  > On 08/25/2011 04:17 AM, Jay Riley wrote:
> >  >
> >  > >
> >  > > And the python exposing is done as follows:
> >  > >
> >  > > class_<Attack, AttackWrapper, boost::shared_ptr<Attack>, bases<Action>
> >  > > >("Attack")
> >  > > .def("CalculateDamage", &AttackWrapper::CalculateDamageDefault);
> >  > >
> >  >
> >  > This bit looks a little suspect, and I'm surprised that it compiles -
> >  > class_ should only take 4 arguments if one of them is boost::noncopyable.
> >  >
> >  > I think you mean:
> >  >
> >  > class_< Attack, boost::shared_ptr<AttackWrapper>, bases<Action> >
> >  > (...)
> >  >
> >  > See
> >  >
> >  > http://www.boost.org/doc/libs/1_47_0/libs/python/doc/v2/class.html
> >  >
> >  > for details of the arguments to class_.
> >  >
> >  > I don't have a good idea as to why this would cause the problem you're
> >  > seeing (maybe you're slicing your AttackWrapper instances into Attack
> >  > instances?) but I'd recommend fixing it first.
> >  >
> >  > Good Luck!
> >  >
> >  > Jim Bosch
> >
> >
> > _______________________________________________
> > Cplusplus-sig mailing list
> > Cplusplus-sig at python.org
> > http://mail.python.org/mailman/listinfo/cplusplus-sig
> 
> _______________________________________________
> Cplusplus-sig mailing list
> Cplusplus-sig at python.org
> http://mail.python.org/mailman/listinfo/cplusplus-sig
 		 	   		  
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.python.org/pipermail/cplusplus-sig/attachments/20110830/faf24350/attachment.html>