libcxx/test/std/strings/basic.string/string.cons/default.pass.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-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 }