Re: [Swig-user] Gotcha with returning a const reference to an object

[Josh C. <jc...@nc...>]

On Wed, 16 Dec 2009, Robert Lupton the Good wrote:

> If I use return-by-const-reference in C++ the recipient cannot modify
> the underlying data (she can end up with a dangling reference, but
> that's a different problem).  If I swig the code, the user *can*
> modify the underlying object --- swig has cast away the const.
>
> This is hinted at in the manual:
>> In Python, there is no detailed distinction like this--specifically,
>> there are only "objects". There are no pointers, references, arrays,
>> and so forth. Because of this, SWIG unifies all of these types
>> together in the wrapper code
>
> In this case the "BBox" is small, so I can modify the class to return
> it by value but it'd be nice if swig generated a warning (and there
> was a note in the manual).

The manual does discuss this explicitly: 
http://www.swig.org/Doc1.3/SWIGPlus.html#SWIGPlus_nn37

I would like to see const supported.  I imagine that it can be done 
without inordinate effort, but that's easy to say when you're not a 
developer.

Josh