text: 
  //  (C) Copyright John Maddock 2005.  
  //  Use, modification and distribution are 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).
  //
  //  See http://www.boost.org/libs/type_traits for most recent version including documentation.
  
  
  #ifndef BOOST_TT_IS_SIGNED_HPP_INCLUDED
  #define BOOST_TT_IS_SIGNED_HPP_INCLUDED
  
  #include <boost/type_traits/is_integral.hpp>
  #include <boost/type_traits/remove_cv.hpp>
  #include <boost/type_traits/is_enum.hpp>
  #include <climits>
  
  namespace boost {
  
  #if !defined( __CODEGEARC__ )
  
  #if !(defined(BOOST_MSVC) && BOOST_MSVC <= 1310) && \
      !(defined(__EDG_VERSION__) && __EDG_VERSION__ <= 238) &&\
      !defined(BOOST_NO_INCLASS_MEMBER_INITIALIZATION)
  
  namespace detail{
  
  template <class T>
  struct is_signed_values
  {
     //
     // Note that we cannot use BOOST_STATIC_CONSTANT here, using enum's
     // rather than "real" static constants simply doesn't work or give
     // the correct answer.
     //
     typedef typename remove_cv<T>::type no_cv_t;
     static const no_cv_t minus_one = (static_cast<no_cv_t>(-1));
     static const no_cv_t zero = (static_cast<no_cv_t>(0));
  };
  
  template <class T>
  struct is_signed_helper
  {
     typedef typename remove_cv<T>::type no_cv_t;
     BOOST_STATIC_CONSTANT(bool, value = (!(::boost::detail::is_signed_values<T>::minus_one  > boost::detail::is_signed_values<T>::zero)));
  };
  
  template <bool integral_type>
  struct is_signed_select_helper
  {
     template <class T>
     struct rebind
     {
        typedef is_signed_helper<T> type;
     };
  };
  
  template <>
  struct is_signed_select_helper<false>
  {
     template <class T>
     struct rebind
     {
        typedef false_type type;
     };
  };
  
  template <class T>
  struct is_signed_impl
  {
     typedef ::boost::detail::is_signed_select_helper< ::boost::is_integral<T>::value || ::boost::is_enum<T>::value> selector;
     typedef typename selector::template rebind<T> binder;
     typedef typename binder::type type;
     BOOST_STATIC_CONSTANT(bool, value = type::value);
  };
  
  }
  
  template <class T> struct is_signed : public integral_constant<bool, boost::detail::is_signed_impl<T>::value> {};
  
  #else
  
  template <class T> struct is_signed : public false_type{};
  
  #endif
  
  #else //defined( __CODEGEARC__ )
     template <class T> struct is_signed : public integral_constant<bool, __is_signed(T)>{};
  #endif
  
  template <> struct is_signed<signed char> : public true_type{};
  template <> struct is_signed<const signed char> : public true_type{};
  template <> struct is_signed<volatile signed char> : public true_type{};
  template <> struct is_signed<const volatile signed char> : public true_type{};
  template <> struct is_signed<short> : public true_type{};
  template <> struct is_signed<const short> : public true_type{};
  template <> struct is_signed<volatile short> : public true_type{};
  template <> struct is_signed<const volatile short> : public true_type{};
  template <> struct is_signed<int> : public true_type{};
  template <> struct is_signed<const int> : public true_type{};
  template <> struct is_signed<volatile int> : public true_type{};
  template <> struct is_signed<const volatile int> : public true_type{};
  template <> struct is_signed<long> : public true_type{};
  template <> struct is_signed<const long> : public true_type{};
  template <> struct is_signed<volatile long> : public true_type{};
  template <> struct is_signed<const volatile long> : public true_type{};
  
  template <> struct is_signed<unsigned char> : public false_type{};
  template <> struct is_signed<const unsigned char> : public false_type{};
  template <> struct is_signed<volatile unsigned char> : public false_type{};
  template <> struct is_signed<const volatile unsigned char> : public false_type{};
  template <> struct is_signed<unsigned short> : public false_type{};
  template <> struct is_signed<const unsigned short> : public false_type{};
  template <> struct is_signed<volatile unsigned short> : public false_type{};
  template <> struct is_signed<const volatile unsigned short> : public false_type{};
  template <> struct is_signed<unsigned int> : public false_type{};
  template <> struct is_signed<const unsigned int> : public false_type{};
  template <> struct is_signed<volatile unsigned int> : public false_type{};
  template <> struct is_signed<const volatile unsigned int> : public false_type{};
  template <> struct is_signed<unsigned long> : public false_type{};
  template <> struct is_signed<const unsigned long> : public false_type{};
  template <> struct is_signed<volatile unsigned long> : public false_type{};
  template <> struct is_signed<const volatile unsigned long> : public false_type{};
  #ifdef BOOST_HAS_LONG_LONG
  template <> struct is_signed< ::boost::long_long_type> : public true_type{};
  template <> struct is_signed<const ::boost::long_long_type> : public true_type{};
  template <> struct is_signed<volatile ::boost::long_long_type> : public true_type{};
  template <> struct is_signed<const volatile ::boost::long_long_type> : public true_type{};
  
  template <> struct is_signed< ::boost::ulong_long_type> : public false_type{};
  template <> struct is_signed<const ::boost::ulong_long_type> : public false_type{};
  template <> struct is_signed<volatile ::boost::ulong_long_type> : public false_type{};
  template <> struct is_signed<const volatile ::boost::ulong_long_type> : public false_type{};
  #endif
  #if defined(CHAR_MIN) 
  #if CHAR_MIN != 0
  template <> struct is_signed<char> : public true_type{};
  template <> struct is_signed<const char> : public true_type{};
  template <> struct is_signed<volatile char> : public true_type{};
  template <> struct is_signed<const volatile char> : public true_type{};
  #else
  template <> struct is_signed<char> : public false_type{};
  template <> struct is_signed<const char> : public false_type{};
  template <> struct is_signed<volatile char> : public false_type{};
  template <> struct is_signed<const volatile char> : public false_type{};
  #endif
  #endif
  #if defined(WCHAR_MIN) && !defined(BOOST_NO_INTRINSIC_WCHAR_T)
  #if WCHAR_MIN != 0
  template <> struct is_signed<wchar_t> : public true_type{};
  template <> struct is_signed<const wchar_t> : public true_type{};
  template <> struct is_signed<volatile wchar_t> : public true_type{};
  template <> struct is_signed<const volatile wchar_t> : public true_type{};
  #else
  template <> struct is_signed<wchar_t> : public false_type{};
  template <> struct is_signed<const wchar_t> : public false_type{};
  template <> struct is_signed<volatile wchar_t> : public false_type{};
  template <> struct is_signed<const volatile wchar_t> : public false_type{};
  #endif
  #endif
  } // namespace boost
  
  #endif // BOOST_TT_IS_MEMBER_FUNCTION_POINTER_HPP_INCLUDED
  