| 1 | //===----------------------------------------------------------------------===// |
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| 2 | // |
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| 3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
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| 4 | // See https://llvm.org/LICENSE.txt for license information. |
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| 5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
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| 6 | // |
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| 7 | //===----------------------------------------------------------------------===// |
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| 8 | |
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| 9 | // UNSUPPORTED: c++03, c++11, c++14, c++17 |
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| 10 | |
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| 11 | // <iterator> |
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| 12 | |
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| 13 | // template <class T, ptrdiff_t N> |
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| 14 | // constexpr ptrdiff_t ssize(const T (&array)[N]) noexcept; |
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| 15 | // |
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| 16 | // This test checks that the library implements LWG3207 as not-a-defect. |
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| 17 | // `clang -m32` is an example of a configuration where using ptrdiff_t |
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| 18 | // instead of size_t in std::ssize has an observable SFINAE effect. |
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| 19 | // |
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| 20 | // REQUIRES: 32-bit-pointer |
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| 21 | |
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| 22 | #include <iterator> |
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| 23 | #include <climits> |
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| 24 | #include <cstddef> |
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| 25 | |
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| 26 | // Test the test: |
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| 27 | static_assert(sizeof(std::ptrdiff_t) == 4, "Run only on these platforms" ); |
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| 28 | static_assert(sizeof(std::size_t) == 4, "Run only on these platforms" ); |
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| 29 | static_assert(std::size_t(PTRDIFF_MAX) + 1 > std::size_t(PTRDIFF_MAX), "This should always be true" ); |
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| 30 | extern char forming_this_type_must_be_valid_on_this_platform[std::size_t(PTRDIFF_MAX) + 1]; |
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| 31 | |
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| 32 | // The actual test: |
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| 33 | template <class T> |
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| 34 | concept HasSsize = requires(T&& t) { std::ssize(t); }; |
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| 35 | |
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| 36 | static_assert(HasSsize<char[std::size_t(PTRDIFF_MAX)]>); |
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| 37 | static_assert(!HasSsize<char[std::size_t(PTRDIFF_MAX) + 1]>); |
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| 38 | |
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