1 // Copyright David Abrahams 2004. Distributed under the Boost
2 // Software License, Version 1.0. (See accompanying
3 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
4 #ifndef IS_WRAPPER_DWA2004723_HPP
5 # define IS_WRAPPER_DWA2004723_HPP
6 
7 # include <boost/python/detail/prefix.hpp>
8 # include <boost/mpl/bool.hpp>
9 
10 namespace boost { namespace python {
11 
12 template <class T> class wrapper;
13 
14 namespace detail
15 {
16   typedef char (&is_not_wrapper)[2];
17   is_not_wrapper is_wrapper_helper(...);
18   template <class T>
19   char is_wrapper_helper(wrapper<T> const volatile*);
20 
21   // A metafunction returning true iff T is [derived from] wrapper<U>
22   template <class T>
23   struct is_wrapper
24     : mpl::bool_<(sizeof(detail::is_wrapper_helper((T*)0)) == 1)>
25   {};
26 
27 }}} // namespace boost::python::detail
28 
29 #endif // IS_WRAPPER_DWA2004723_HPP
30