Mark Russell <mrussell8081@[...].net>  writes:

>  Hi Dave,

Hi Mark. Please post Boost.Python questions to the C++-sig:

    http://www.python.org/sigs/c++-sig

>  I am using Boost Python to wrap DirectX and have run into a problem
>  I can't seem to get around.  Def seems to have trouble with
>  __stdcall this works ok for me when I call bind directly so I'm not
>  sure where to go from here.  I have attached a short test example
>  cloned from the bind tests to show you where the problem is.  I am
>  using msvc 6.5 and have tried both boost 1.29 and the latest from
>  CVS.  Thanks in advance -- great library!  I am very excited to be
>  working with it.

Thanks, I'm excited that so many people are using it!
> 
>  Test Code:
> 
>  #define BOOST_BIND_ENABLE_STDCALL
>  #define BOOST_MEM_FN_ENABLE_STDCALL
> 
>  #include <boost/python.hpp>
>  using namespace boost::python;
> 
>  long __stdcall f_0()
>  {
>      return 17041L;
>  }
> 
> 
>  BOOST_PYTHON_MODULE_INIT(test_std_call)
>  {
>      def("f_0", f_0);
> 
>  }
> 
>  Error Message:
> 
>  Compiling...
>  stdcall.cpp
>  c:\boost\boost\python\detail\arg_tuple_size.hpp(61) : error C2664: 'struct
>  boost::python::detail::char_array<0> __cdecl
>  boost::python::detail::arg_tuple_size_helper(long (__cdecl *)(void))' :
>  cannot convert parameter 1 from 'long (__stdcall *)(void)
>  ' to 'long (__cdecl *)(void)'
>          This conversion requires a reinterpret_cast, a C-style cast or
>  function-style cast

Right. The problem is that there are lots of Boost.Python components
which don't account for the presence of "extralegal" constructs like
__stdcall and __fastcall. In order to handle these automatically we'd
need, at the very least, to extend
boost/python/detail/arg_tuple_size.hpp to handle these cases, and I'm
guessing that there are a quite a few other places like that in the
code as well (e.g. boost/python/detail/returning.hpp). Here are your
choices:

1. Implement the extensions yourself and submit a patch. We'd really
   love that!

2. Write "thin wrapper" functions around all the functions you want to
   wrap, and wrap the wrappers:

   long f_0_aux() { return f_0(); }
   ...
      def("f_0", f_0_aux);

3. Wait for us to get around to extending Boost.Python to deal with
   __stdcall. Joel may be working on an ActiveX project soon himself,
   so it's not an impossibility that it will happen. However, this is
   still somewhat of a long shot.

-- 
                       David Abrahams
   dave@[...].com * http://www.boost-consulting.com
Boost support, enhancements, training, and commercial distribution


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