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