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 // basic_string() noexcept(is_nothrow_default_constructible<allocator_type>::value); // constexpr since C++20 12 13 #include <cassert> 14 #include <string> 15 16 #include "test_macros.h" 17 #include "test_allocator.h" 18 19 #if TEST_STD_VER >= 11 20 // Test the noexcept specification, which is a conforming extension 21 LIBCPP_STATIC_ASSERT(std::is_nothrow_default_constructible<std::string>::value, ""); 22 LIBCPP_STATIC_ASSERT(std::is_nothrow_default_constructible< 23 std::basic_string<char, std::char_traits<char>, test_allocator<char>>>::value, 24 ""); 25 LIBCPP_STATIC_ASSERT(!std::is_nothrow_default_constructible< 26 std::basic_string<char, std::char_traits<char>, limited_allocator<char, 10>>>::value, 27 ""); 28 #endif 29 30 TEST_CONSTEXPR_CXX20 bool test() { 31 std::string str; 32 assert(str.empty()); 33 34 return true; 35 } 36 37 int main(int, char**) { 38 test(); 39 #if TEST_STD_VER > 17 40 static_assert(test()); 41 #endif 42 43 return 0; 44 } 45