libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_union.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 // type_traits
  10
  11 // is_union
  12
  13 #include <type_traits>
  14 #include <cstddef>        // for std::nullptr_t
  15 #include "test_macros.h"
  16
  17 template <class T>
  18 void test_is_union()
  19 {
  20     static_assert( std::is_union<T>::value, "");
  21     static_assert( std::is_union<const T>::value, "");
  22     static_assert( std::is_union<volatile T>::value, "");
  23     static_assert( std::is_union<const volatile T>::value, "");
  24 #if TEST_STD_VER > 14
  25     static_assert( std::is_union_v<T>, "");
  26     static_assert( std::is_union_v<const T>, "");
  27     static_assert( std::is_union_v<volatile T>, "");
  28     static_assert( std::is_union_v<const volatile T>, "");
  29 #endif
  30 }
  31
  32 template <class T>
  33 void test_is_not_union()
  34 {
  35     static_assert(!std::is_union<T>::value, "");
  36     static_assert(!std::is_union<const T>::value, "");
  37     static_assert(!std::is_union<volatile T>::value, "");
  38     static_assert(!std::is_union<const volatile T>::value, "");
  39 #if TEST_STD_VER > 14
  40     static_assert(!std::is_union_v<T>, "");
  41     static_assert(!std::is_union_v<const T>, "");
  42     static_assert(!std::is_union_v<volatile T>, "");
  43     static_assert(!std::is_union_v<const volatile T>, "");
  44 #endif
  45 }
  46
  47 class Empty
  48 {
  49 };
  50
  51 class NotEmpty
  52 {
  53     virtual ~NotEmpty();
  54 };
  55
  56 union Union {};
  57
  58 struct bit_zero
  59 {
  60     int :  0;
  61 };
  62
  63 class Abstract
  64 {
  65     virtual ~Abstract() = 0;
  66 };
  67
  68 enum Enum {zero, one};
  69 struct incomplete_type;
  70
  71 typedef void (*FunctionPtr)();
  72
  73 int main(int, char**)
  74 {
  75     test_is_union<Union>();
  76
  77     test_is_not_union<std::nullptr_t>();
  78     test_is_not_union<void>();
  79     test_is_not_union<int>();
  80     test_is_not_union<int&>();
  81     test_is_not_union<int&&>();
  82     test_is_not_union<int*>();
  83     test_is_not_union<double>();
  84     test_is_not_union<const int*>();
  85     test_is_not_union<char[3]>();
  86     test_is_not_union<char[]>();
  87     test_is_not_union<Enum>();
  88     test_is_not_union<FunctionPtr>();
  89     test_is_not_union<Empty>();
  90     test_is_not_union<bit_zero>();
  91     test_is_not_union<NotEmpty>();
  92     test_is_not_union<Abstract>();
  93     test_is_not_union<incomplete_type>();
  94
  95   return 0;
  96 }