libstdc++-v3/testsuite/23_containers/array/element_access/constexpr_c++17.cc

   1 // { dg-do compile { target c++17 } }
   2 // { dg-add-options no_pch }
   3
   4 // Copyright (C) 2011-2024 Free Software Foundation, Inc.
   5 //
   6 // This file is part of the GNU ISO C++ Library.  This library is free
   7 // software; you can redistribute it and/or modify it under the
   8 // terms of the GNU General Public License as published by the
   9 // Free Software Foundation; either version 3, or (at your option)
  10 // any later version.
  11
  12 // This library is distributed in the hope that it will be useful,
  13 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 // GNU General Public License for more details.
  16
  17 // You should have received a copy of the GNU General Public License along
  18 // with this library; see the file COPYING3.  If not see
  19 // <http://www.gnu.org/licenses/>.
  20
  21 #include <array>
  22
  23 #ifndef __cpp_lib_array_constexpr
  24 # error "Feature test macro for array constexpr is missing in <array>"
  25 #elif __cpp_lib_array_constexpr < 201603L
  26 # error "Feature test macro for array constexpr has wrong value in <array>"
  27 #endif
  28
  29 constexpr std::size_t test01()
  30 {
  31   // array
  32   typedef std::array<std::size_t, 6> array_type;
  33   array_type a = { { 0, 55, 66, 99, 4115, 2 } };
  34   auto v1  = a[1];
  35   auto v2  = a.at(2);
  36   auto v3  = a.front();
  37   auto v4  = a.back();
  38   auto v5 = *a.data();
  39   return v1 + v2 + v3 + v4 + v5;
  40 }
  41
  42 static_assert( test01() == (55 + 66 + 0 + 2) );
  43
  44 constexpr std::size_t test02()
  45 {
  46   // const array
  47   typedef std::array<std::size_t, 6> array_type;
  48   const array_type a = { { 0, 55, 66, 99, 4115, 2 } };
  49   auto v1  = a[1];
  50   auto v2  = a.at(2);
  51   auto v3  = a.front();
  52   auto v4  = a.back();
  53   auto v5 = *a.data();
  54   return v1 + v2 + v3 + v4 + v5;
  55 }
  56
  57 static_assert( test02() == (55 + 66 + 0 + 2) );
  58
  59 constexpr bool test_zero()
  60 {
  61   // zero-sized array (PR libstdc++/108258)
  62   std::array<int, 0> a{};
  63   auto v4 = a.data();
  64   // The standard says this is unspecified, it's null for our implementation:
  65   return a.data() == nullptr;
  66 }
  67
  68 static_assert( test_zero() );