[C++-sig] variable argument number and BOOST_PYTHON_MEMBER_FUNCTION_OVERLOADS

[William Ladwig]

I haven't tried this myself, but I think all you need to do to wrap the member function is this:

.def("info", (void(A::*)(int))0, A_info_overloads());

Hope this helps,
Bill

-----Original Message-----
From: cplusplus-sig-bounces+wladwig=wdtinc.com at python.org [mailto:cplusplus-sig-bounces+wladwig=wdtinc.com at python.org] On Behalf Of Hans Roessler
Sent: Thursday, May 21, 2009 8:40 AM
To: cplusplus-sig at python.org
Subject: [C++-sig] variable argument number and BOOST_PYTHON_MEMBER_FUNCTION_OVERLOADS


Hello,
I try to wrap a class with a function info([int arg]) that takes either zero or one argument (exact colde below). For some reason I can't get BOOST_PYTHON_MEMBER_FUNCTION_OVERLOADS to work.

The examples at http://www.boost.org/doc/libs/1_39_0/libs/python/doc/tutorial/doc/html/python/functions.html#python.overloading and
http://www.boost.org/doc/libs/1_39_0/libs/python/doc/v2/overloads.html#BOOST_PYTHON_FUNCTION_OVERLOADS-spec only show the situation where either
- the *member* function has up to three arguments with default values assigned or
- three *free* functions have one to three  arguments.

I don't find an example where a class has several *member* functions with the same name, that take a variable number of (non-default!) arguments.

My attempt below gives the error
"pytest.cpp:17: error: no matching function for call to 'boost::python::class_<A, boost::python::detail::not_specified, boost::python::detail::not_specified, boost::python::detail::not_specified>::def(const char [5], <unresolved overloaded function type>, A_info_overloads)'"

Do I have to replace the ".def("info",&A::info, ..." with something like  ".def("foo", (void(*)(int,int))0, ..." as shown in the Auto-Overloading section in the tutorial? If yes, how must this function signature look like? It doesn't work like this.

Hope someone can help
Hans

=== pytest.py ===
#include <boost/python.hpp>
#include <stdio.h>

using namespace boost::python;

class A{
public:
  void info() {printf("This is an A\n");}
  void info(int arg) {printf("Unnecessary arg.\n");}
};

BOOST_PYTHON_MEMBER_FUNCTION_OVERLOADS(A_info_overloads, info, 0,1)

BOOST_PYTHON_MODULE(test)
{
  class_<A>("A")
      .def("info",&A::info,A_info_overloads()) //line 17
    ;
}



      
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