libcxx/test/std/utilities/variant/variant.variant/variant.status/valueless_by_exception.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
  10
  11 // <variant>
  12
  13 // template <class ...Types> class variant;
  14
  15 // constexpr bool valueless_by_exception() const noexcept;
  16
  17 #include <cassert>
  18 #include <string>
  19 #include <type_traits>
  20 #include <variant>
  21
  22 #include "archetypes.h"
  23 #include "test_macros.h"
  24 #include "variant_test_helpers.h"
  25
  26
  27 int main(int, char**) {
  28   {
  29     using V = std::variant<int, long>;
  30     constexpr V v;
  31     static_assert(!v.valueless_by_exception(), "");
  32   }
  33   {
  34     using V = std::variant<int, long>;
  35     V v;
  36     assert(!v.valueless_by_exception());
  37   }
  38   {
  39     using V = std::variant<int, long, std::string>;
  40     const V v("abc");
  41     assert(!v.valueless_by_exception());
  42   }
  43 #ifndef TEST_HAS_NO_EXCEPTIONS
  44   {
  45     using V = std::variant<int, MakeEmptyT>;
  46     V v;
  47     assert(!v.valueless_by_exception());
  48     makeEmpty(v);
  49     assert(v.valueless_by_exception());
  50   }
  51 #endif
  52
  53   return 0;
  54 }