libstdc++-v3/testsuite/20_util/aligned_union/1.cc

   1 // { dg-do compile { target c++11 } }
   2
   3 // 2014-04-16 Rüdiger Sonderfeld  <ruediger@c-plusplus.de>
   4
   5 // Copyright (C) 2014-2018 Free Software Foundation, Inc.
   6 //
   7 // This file is part of the GNU ISO C++ Library.  This library is free
   8 // software; you can redistribute it and/or modify it under the terms
   9 // of the GNU General Public License as published by the Free Software
  10 // Foundation; either version 3, or (at your option) any later
  11 // version.
  12
  13 // This library is distributed in the hope that it will be useful, but
  14 // WITHOUT ANY WARRANTY; without even the implied warranty of
  15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16 // General Public License for more details.
  17
  18 // You should have received a copy of the GNU General Public License
  19 // along with this library; see the file COPYING3.  If not see
  20 // <http://www.gnu.org/licenses/>.
  21
  22 // C++11 [meta.trans.other] 20.9.7.6: aligned_union
  23
  24 #include <type_traits>
  25 #include <testsuite_tr1.h>
  26
  27 struct MSAlignType { } __attribute__((__aligned__));
  28
  29 template<typename...T>
  30   struct mymax
  31   {
  32     static const std::size_t alignment = 0;
  33     static const std::size_t size = 0;
  34   };
  35
  36 template<typename L,  typename...T>
  37   struct mymax<L, T...>
  38   {
  39     static const std::size_t alignment = alignof(L) > mymax<T...>::alignment
  40       ? alignof(L) : mymax<T...>::alignment;
  41     static const std::size_t size = sizeof(L) > mymax<T...>::size
  42       ? sizeof(L) : mymax<T...>::size;
  43   };
  44
  45 void test01()
  46 {
  47   using std::aligned_union;
  48   using std::alignment_of;
  49   using std::size_t;
  50   using namespace __gnu_test;
  51
  52   const size_t max_a = mymax<char, short, int, double, int[4],
  53                              ClassType, MSAlignType>::alignment;
  54   const size_t max_s = mymax<char, short, int, double, int[4],
  55                              ClassType, MSAlignType>::size;
  56
  57   typedef aligned_union<0, char, short, int, double, int[4],
  58                         ClassType, MSAlignType> au_type;
  59   static_assert(au_type::alignment_value == max_a, "Alignment value");
  60   static_assert(sizeof(au_type::type) >= max_s, "Storage size");
  61
  62   typedef aligned_union<max_s+100, char, short, int, double, int[4],
  63                         ClassType, MSAlignType> au_type2;
  64   static_assert(sizeof(au_type2::type) >= max_s+100,
  65                 "Storage size (at least len)");
  66 }
  67
  68 int main()
  69 {
  70   test01();
  71 }