1 #ifndef _LIBCPP_TYPE_TRAITS
2 #define _LIBCPP_TYPE_TRAITS
3 
4 
5 template <class _Tp>
6 struct underlying_type
7 {
8     typedef __underlying_type(_Tp) type;
9 };
10 
11 #endif  // _LIBCPP_TYPE_TRAITS
12 
13 #include "B.h"
14