58 lines · cpp
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-exception6//7//===----------------------------------------------------------------------===//8 9// UNSUPPORTED: !stdlib=libc++ && (c++03 || c++11 || c++14)10 11// <string_view>12 13// constexpr const _CharT& back();14 15#include <string_view>16#include <cassert>17 18#include "test_macros.h"19 20template <typename CharT>21bool test(const CharT* s, std::size_t len) {22 typedef std::basic_string_view<CharT> SV;23 SV sv(s, len);24 ASSERT_SAME_TYPE(decltype(sv.front()), typename SV::const_reference);25 LIBCPP_ASSERT_NOEXCEPT(sv.front());26 assert(sv.length() == len);27 assert(sv.front() == s[0]);28 return &sv.front() == s;29}30 31int main(int, char**) {32 assert(test("ABCDE", 5));33 assert(test("a", 1));34 35#ifndef TEST_HAS_NO_WIDE_CHARACTERS36 assert(test(L"ABCDE", 5));37 assert(test(L"a", 1));38#endif39 40#if TEST_STD_VER >= 1141 assert(test(u"ABCDE", 5));42 assert(test(u"a", 1));43 44 assert(test(U"ABCDE", 5));45 assert(test(U"a", 1));46#endif47 48#if TEST_STD_VER >= 1149 {50 constexpr std::basic_string_view<char> sv("ABC", 2);51 static_assert(sv.length() == 2, "");52 static_assert(sv.front() == 'A', "");53 }54#endif55 56 return 0;57}58