1 //===----------------------------------------------------------------------===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is dual licensed under the MIT and the University of Illinois Open 6 // Source Licenses. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 10 // <memory> 11 12 // template <class Alloc> 13 // struct allocator_traits 14 // { 15 // typedef Alloc::difference_type 16 // | pointer_traits<pointer>::difference_type difference_type; 17 // ... 18 // }; 19 20 #include <memory> 21 #include <type_traits> 22 23 #include "test_macros.h" 24 25 template <class T> 26 struct A 27 { 28 typedef T value_type; 29 typedef short difference_type; 30 }; 31 32 template <class T> 33 struct B 34 { 35 typedef T value_type; 36 }; 37 38 template <class T> 39 struct C 40 { 41 typedef T value_type; 42 struct pointer {}; 43 struct const_pointer {}; 44 struct void_pointer {}; 45 struct const_void_pointer {}; 46 }; 47 48 49 template <class T> 50 struct D 51 { 52 typedef T value_type; 53 private: 54 typedef void difference_type; 55 }; 56 57 namespace std 58 { 59 60 template <> 61 struct pointer_traits<C<char>::pointer> 62 { 63 typedef C<char>::pointer pointer; 64 typedef char element_type; 65 typedef signed char difference_type; 66 }; 67 68 } 69 70 int main() 71 { 72 static_assert((std::is_same<std::allocator_traits<A<char> >::difference_type, short>::value), ""); 73 static_assert((std::is_same<std::allocator_traits<B<char> >::difference_type, std::ptrdiff_t>::value), ""); 74 static_assert((std::is_same<std::allocator_traits<C<char> >::difference_type, signed char>::value), ""); 75 #if TEST_STD_VER >= 11 76 static_assert((std::is_same<std::allocator_traits<D<char> >::difference_type, std::ptrdiff_t>::value), ""); 77 #endif 78 } 79
