// Copyright David Abrahams 2004. Use, modification and distribution is

 // subject to the Boost Software License, Version 1.0. (See accompanying

 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)

 #ifndef IS_INCREMENTABLE_DWA200415_HPP

 # define IS_INCREMENTABLE_DWA200415_HPP

 # include <boost/type_traits/detail/template_arity_spec.hpp>

 # include <boost/type_traits/remove_cv.hpp>

 # include <boost/mpl/aux_/lambda_support.hpp>

 # include <boost/mpl/bool.hpp>

 # include <boost/detail/workaround.hpp>

 // Must be the last include

 # include <boost/type_traits/detail/bool_trait_def.hpp>

 namespace boost { namespace detail { 

 // is_incrementable<T> metafunction

 //

 // Requires: Given x of type T&, if the expression ++x is well-formed

 // it must have complete type; otherwise, it must neither be ambiguous

 // nor violate access.

 // This namespace ensures that ADL doesn't mess things up.

 namespace is_incrementable_

 {

   // a type returned from operator++ when no increment is found in the

   // type's own namespace

   struct tag {};

   // any soaks up implicit conversions and makes the following

   // operator++ less-preferred than any other such operator that

   // might be found via ADL.

   struct any { template <class T> any(T const&); };

   // This is a last-resort operator++ for when none other is found

 # if BOOST_WORKAROUND(__GNUC__, == 4) && __GNUC_MINOR__ == 0 && __GNUC_PATCHLEVEL__ == 2

 }

 namespace is_incrementable_2

 {

   is_incrementable_::tag operator++(is_incrementable_::any const&);

   is_incrementable_::tag operator++(is_incrementable_::any const&,int);

 }

 using namespace is_incrementable_2;

 namespace is_incrementable_

 {

 # else

   tag operator++(any const&);

   tag operator++(any const&,int);

 # endif 

 # if BOOST_WORKAROUND(__MWERKS__, BOOST_TESTED_AT(0x3202)) \

     || BOOST_WORKAROUND(BOOST_MSVC, <= 1300)

 #  define BOOST_comma(a,b) (a)

 # else 

   // In case an operator++ is found that returns void, we'll use ++x,0

   tag operator,(tag,int);  

 #  define BOOST_comma(a,b) (a,b)

 # endif 

   // two check overloads help us identify which operator++ was picked

   char (& check(tag) )[2];

   template <class T>

   char check(T const&);

   template <class T>

   struct impl

   {

       static typename boost::remove_cv<T>::type& x;

       BOOST_STATIC_CONSTANT(

           bool

         , value = sizeof(is_incrementable_::check(BOOST_comma(++x,0))) == 1

       );

   };

   template <class T>

   struct postfix_impl

   {

       static typename boost::remove_cv<T>::type& x;

       BOOST_STATIC_CONSTANT(

           bool

         , value = sizeof(is_incrementable_::check(BOOST_comma(x++,0))) == 1

       );

   };

 }

 # undef BOOST_comma

 template<typename T> 

 struct is_incrementable 

 BOOST_TT_AUX_BOOL_C_BASE(::boost::detail::is_incrementable_::impl<T>::value)

 { 

     BOOST_TT_AUX_BOOL_TRAIT_VALUE_DECL(::boost::detail::is_incrementable_::impl<T>::value)

     BOOST_MPL_AUX_LAMBDA_SUPPORT(1,is_incrementable,(T))

 };

 template<typename T> 

 struct is_postfix_incrementable 

 BOOST_TT_AUX_BOOL_C_BASE(::boost::detail::is_incrementable_::impl<T>::value)

 { 

     BOOST_TT_AUX_BOOL_TRAIT_VALUE_DECL(::boost::detail::is_incrementable_::postfix_impl<T>::value)

     BOOST_MPL_AUX_LAMBDA_SUPPORT(1,is_postfix_incrementable,(T))

 };

 } // namespace detail

 BOOST_TT_AUX_TEMPLATE_ARITY_SPEC(1, ::boost::detail::is_incrementable)

 BOOST_TT_AUX_TEMPLATE_ARITY_SPEC(1, ::boost::detail::is_postfix_incrementable)

 } // namespace boost

 # include <boost/type_traits/detail/bool_trait_undef.hpp>

 #endif // IS_INCREMENTABLE_DWA200415_HPP