libcxx/test/std/utilities/variant/variant.get/holds_alternative.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 T, class... Types>
  14 // constexpr bool holds_alternative(const variant<Types...>& v) noexcept;
  15
  16 #include "test_macros.h"
  17 #include <variant>
  18
  19 int main(int, char**) {
  20   {
  21     using V = std::variant<int>;
  22     constexpr V v;
  23     static_assert(std::holds_alternative<int>(v), "");
  24   }
  25   {
  26     using V = std::variant<int, long>;
  27     constexpr V v;
  28     static_assert(std::holds_alternative<int>(v), "");
  29     static_assert(!std::holds_alternative<long>(v), "");
  30   }
  31   { // noexcept test
  32     using V = std::variant<int>;
  33     const V v;
  34     ASSERT_NOEXCEPT(std::holds_alternative<int>(v));
  35   }
  36
  37   return 0;
  38 }