libcxx/test/std/utilities/charconv/charconv.syn/from_chars_result.operator_bool.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 // UNSUPPORTED: c++03, c++11, c++14, c++17, c++20, c++23
  10
  11 // <charconv>
  12
  13 // struct from_chars_result
  14 //   constexpr explicit operator bool() const noexcept { return ec == errc{}; }
  15
  16 #include <charconv>
  17
  18 #include <cassert>
  19 #include <system_error>
  20 #include <type_traits>
  21
  22 #include "test_macros.h"
  23
  24 static_assert(!std::is_convertible_v<std::from_chars_result, bool>);
  25 static_assert(std::is_constructible_v<bool, std::from_chars_result>);
  26
  27 constexpr bool test() {
  28   // True
  29   {
  30     std::from_chars_result value{nullptr, std::errc{}};
  31     assert(bool(value) == true);
  32     static_assert(noexcept(bool(value)) == true);
  33   }
  34   // False
  35   {
  36     std::from_chars_result value{nullptr, std::errc::value_too_large};
  37     assert(bool(value) == false);
  38     static_assert(noexcept(bool(value)) == true);
  39   }
  40
  41   return true;
  42 }
  43
  44 int main(int, char**) {
  45   assert(test());
  46   static_assert(test());
  47
  48   return 0;
  49 }