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 // <string> 10 11 // const_reverse_iterator crbegin() const; // constexpr since C++20 12 13 #include <string> 14 #include <cassert> 15 16 #include "test_macros.h" 17 #include "min_allocator.h" 18 19 template <class S> 20 TEST_CONSTEXPR_CXX20 void test(const S& s) { 21 typename S::const_reverse_iterator cb = s.crbegin(); 22 if (!s.empty()) { 23 assert(*cb == s.back()); 24 } 25 assert(cb == s.rbegin()); 26 } 27 28 TEST_CONSTEXPR_CXX20 bool test() { 29 { 30 typedef std::string S; 31 test(S()); 32 test(S("123")); 33 } 34 #if TEST_STD_VER >= 11 35 { 36 typedef std::basic_string<char, std::char_traits<char>, min_allocator<char>> S; 37 test(S()); 38 test(S("123")); 39 } 40 #endif 41 42 return true; 43 } 44 45 int main(int, char**) { 46 test(); 47 #if TEST_STD_VER > 17 48 static_assert(test()); 49 #endif 50 51 return 0; 52 } 53