47 lines · 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-exception6//7//===----------------------------------------------------------------------===//8 9// UNSUPPORTED: c++03, c++11, c++1410 11// <variant>12 13// template <class T> struct variant_size; // undefined14// template <class T> struct variant_size<const T>;15// template <class T> struct variant_size<volatile T>;16// template <class T> struct variant_size<const volatile T>;17// template <class T> constexpr size_t variant_size_v18// = variant_size<T>::value;19 20#include <memory>21#include <type_traits>22#include <variant>23 24#include "test_macros.h"25 26template <class V, std::size_t E> void test() {27 static_assert(std::variant_size<V>::value == E, "");28 static_assert(std::variant_size<const V>::value == E, "");29 static_assert(std::variant_size<volatile V>::value == E, "");30 static_assert(std::variant_size<const volatile V>::value == E, "");31 static_assert(std::variant_size_v<V> == E, "");32 static_assert(std::variant_size_v<const V> == E, "");33 static_assert(std::variant_size_v<volatile V> == E, "");34 static_assert(std::variant_size_v<const volatile V> == E, "");35 static_assert(std::is_base_of<std::integral_constant<std::size_t, E>,36 std::variant_size<V>>::value,37 "");38};39 40int main(int, char**) {41 test<std::variant<>, 0>();42 test<std::variant<void *>, 1>();43 test<std::variant<long, long, void *, double>, 4>();44 45 return 0;46}47