1 // -*- C++ -*- 2 //===----------------------------------------------------------------------===// 3 // 4 // The LLVM Compiler Infrastructure 5 // 6 // This file is dual licensed under the MIT and the University of Illinois Open 7 // Source Licenses. See LICENSE.TXT for details. 8 // 9 //===----------------------------------------------------------------------===// 10 11 // UNSUPPORTED: c++98, c++03, c++11, c++14 12 13 // <variant> 14 15 // template <class T> struct variant_size; // undefined 16 // template <class T> struct variant_size<const T>; 17 // template <class T> struct variant_size<volatile T>; 18 // template <class T> struct variant_size<const volatile T>; 19 // template <class T> constexpr size_t variant_size_v 20 // = variant_size<T>::value; 21 22 #include <memory> 23 #include <type_traits> 24 #include <variant> 25 26 template <class V, 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 40 int main() { 41 test<std::variant<>, 0>(); 42 test<std::variant<void *>, 1>(); 43 test<std::variant<long, long, void *, double>, 4>(); 44 } 45
