[boost] boost::bind, problem with result type deduction and calling conventions

Subject: [boost] boost::bind, problem with result type deduction and calling conventions
From: Ingo.Loehken_at_[hidden]
Date: 2009-02-25 03:41:37

hi,
anybody able to explain, why the code for the result type,
related to special calling conventions defines an void
return type ?

template< class R, class T >
struct add_cref< R (T::*) (), 1 >
{
    typedef void type;
};

so that code like

  class A
  {
  public:
    int __stdcall x()
    {
      return 0;
    }

    void const y() {}

    explicit A()
    {
      typedef boost::function<int()> fun_t;

      fun_t const f(boost::bind(&A::x,this));
    }
  };

ends up with an warning at bind

1>G:\boost\boost_1_37_0\boost/bind.hpp(1643) : warning C4180: qualifier 
applied to function type has no meaning; ignored
1>        G:\boost\boost_1_37_0\boost/bind.hpp(1682) : see reference to 
class template instantiation 'boost::_bi::add_cref<Pm,I>' being compiled
1>        with
1>        [
1>            Pm=int (__stdcall Ado::A::* )(void),
1>            I=1
1>        ]
1>        G:\dev\workspace\files\ado\ado_bind.hxx(36) : see reference to 
class template instantiation 'boost::_bi::dm_result<Pm,A1>' being compiled
1>        with
1>        [
1>            Pm=int (__stdcall Ado::A::* )(void),
1>            A1=Ado::A *
1>        ]

because the proposed specialization is not choosen by the compiler.
Adding an __stdcall to the function signature type in add_cref fixes
that problem, but still i do no understand, why the defintion is not
like

template< class M, class T > struct add_cref< M (__stdcall T::*) (), 1 >
{
    typedef M const& type;
};

and of course that fix is only applicable for __stdcall, where 
specialzations
for other calling conventions can easily be generated, like for mem_fn_cc 
in
respect to requested support for calling conventions.

Thanks for your help, ILo.

compiler : msvc 8.0
library :  boost 1.38