Re: [pygccxml-development] problem with private classes

[Roman Y. <rom...@gm...>]

On Tue, Jul 8, 2008 at 5:03 AM, Gordon Wrigley <gor...@gm...> wrote:
> I think I found another bug, but I'm not sure who's bug it is. This:
>
> class Alpha
> {
> private:
>   class Omega
>   {
>     <snip>
>   }
>
> public:
>   Omega *pOmega;
> }
>
> produces:
>
> static ::Alpha::Omega * get_pOmega(Alpha const & inst ){
>   return inst.pOmega;
> }
>
> which leads to:
>
> extending.cpp(634) : error C2248: 'Alpha::Omega' : cannot access private
> class declared in class 'Alpha'
>         c:\program
> files\boost\boost_1_35_0\libs\python\example\bobit.h(1458) : see declaration
> of 'Alpha::Omega'
>         c:\program
> files\boost\boost_1_35_0\libs\python\example\bobit.h(1223) : see declaration
> of 'Alpha'

The example you posted could not be compiled with gccxml: The error is:

Error occured during code generation process!
Error:
Error occured while running GCC-XML: d:\tmp\yyy.h: In function
'Alpha::Omega* get_pOmega(const Alpha&)':
d:\tmp\yyy.h:5: error: 'class Alpha::Omega' is private
d:\tmp\yyy.h:11: error: within this context

I guess the actual code looks like:

class Alpha
{
private:
  class Omega
  {};
public:
    typedef Omega Om;

public:
  Omega *pOmega;
};

static ::Alpha::Om * get_pOmega(Alpha const & inst ){
  return inst.pOmega;
}


Now these are the warning I've got during the code generation process:

> warning W1025: Py++ will generate class wrapper - class contains
> "pOmega" - T* member variable

WARNING: Alpha::Omega * get_pOmega(Alpha const & inst) [free function]
> compilation error W1005: Py++ cannot expose function that takes as
> argument/returns instance of non-public class. Generated code will not
> compile.


WARNING: Alpha::Omega * get_pOmega(Alpha const & inst) [free function]
> compilation error W1050: The function returns "Alpha::Omega *" type.
> You have to specify a call policies.Be sure to take a look on Py++
> defined call policies: http://language-
> binding.net/pyplusplus/documentation/functions/call_policies.html#py-
> defined-call-policies


WARNING: Alpha::Omega [class]
> execution error W1040: The declaration is unexposed, but there are
> other declarations, which refer to it. This could cause "no to_python
> converter found" run time error. Declarations:    Alpha::pOmega
> [variable]


The last warning warns you about that. Now you can decide what you
want to do. In my opinion this is just a mistake in the code, but I
could be wrong.

Anyway if you want to exclude declarations, based on warnings they
produce, you can do this too:

http://language-binding.net/pyplusplus/documentation/warnings.html

HTH

-- 
Roman Yakovenko
C++ Python language binding
http://www.language-binding.net/