test/std/utilities/memory/pointer.traits/pointer.traits.types/difference_type.pass.cpp

//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

// <memory>

// template <class Ptr>
// struct pointer_traits
// {
//     typedef <details> difference_type;
//     ...
// };

#include <memory>
#include <type_traits>

#include "test_macros.h"

struct A
{
    typedef short element_type;
    typedef char difference_type;
};

struct B
{
    typedef short element_type;
};

template <class T>
struct C {};

template <class T>
struct D
{
    typedef char difference_type;
};

template <class T>
struct E
{
    static int difference_type;
};

template <class T>
struct F {
private:
  typedef int difference_type;
};

int main(int, char**)
{
    static_assert((std::is_same<std::pointer_traits<A>::difference_type, char>::value), "");
    static_assert((std::is_same<std::pointer_traits<B>::difference_type, std::ptrdiff_t>::value), "");
    static_assert((std::is_same<std::pointer_traits<C<double> >::difference_type, std::ptrdiff_t>::value), "");
    static_assert((std::is_same<std::pointer_traits<D<int> >::difference_type, char>::value), "");
    static_assert((std::is_same<std::pointer_traits<E<int> >::difference_type, std::ptrdiff_t>::value), "");
#if TEST_STD_VER >= 11
    static_assert((std::is_same<std::pointer_traits<F<int>>::difference_type, std::ptrdiff_t>::value), "");
#endif

  return 0;
}