85d4e29fd8
Instead of overloading `__to_address`, let's specialize `pointer_traits`. Function overloads need to be in scope at the point where they're called, whereas template specializations do not. (User code can provide pointer_traits specializations to be used by already-included library code, so obviously `__wrap_iter` can do the same.) `pointer_traits<__wrap_iter<It>>` cannot provide `pointer_to`, because you generally cannot create a `__wrap_iter` without also knowing the identity of the container into which you're trying to create an iterator. I believe this is OK; contiguous iterators are required to provide `to_address` but *not* necessarily `pointer_to`. Differential Revision: https://reviews.llvm.org/D110198
54 lines
1.6 KiB
C++
54 lines
1.6 KiB
C++
//===----------------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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// <memory>
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// template <class T>
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// struct pointer_traits<T*>
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// {
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// static pointer pointer_to(<details>); // constexpr in C++20
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// ...
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// };
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#include <memory>
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#include <cassert>
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#include "test_macros.h"
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TEST_CONSTEXPR_CXX20 bool test()
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{
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{
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int i = 0;
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static_assert(std::is_same<decltype(std::pointer_traits<int*>::pointer_to(i)), int*>::value, "");
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assert(std::pointer_traits<int*>::pointer_to(i) == &i);
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}
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{
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int i = 0;
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static_assert(std::is_same<decltype(std::pointer_traits<const int*>::pointer_to(i)), const int*>::value, "");
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assert(std::pointer_traits<const int*>::pointer_to(i) == &i);
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}
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return true;
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}
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int main(int, char**)
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{
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test();
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#if TEST_STD_VER > 17
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static_assert(test());
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#endif
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{
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// Check that pointer_traits<void*> is still well-formed, even though it has no pointer_to.
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static_assert(std::is_same<std::pointer_traits<void*>::element_type, void>::value, "");
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static_assert(std::is_same<std::pointer_traits<const void*>::element_type, const void>::value, "");
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static_assert(std::is_same<std::pointer_traits<volatile void*>::element_type, volatile void>::value, "");
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}
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return 0;
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}
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