libstdc++-v3/testsuite/21_strings/char_traits/requirements/constexpr_functions_c++20.cc

   1 // { dg-options "-std=gnu++20" }
   2 // { dg-do compile { target c++20 } }
   3
   4 // Copyright (C) 2017-2022 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 <string>
  22
  23 template<typename CT>
  24   constexpr bool
  25   test_move()
  26   {
  27     using char_type = typename CT::char_type;
  28
  29     // Overlapping strings
  30     char_type s1[3] = {1, 2, 3};
  31     CT::move(s1+1, s1, 2);
  32     if (s1[0] != char_type{1} || s1[1] != char_type{1} || s1[2] != char_type{2})
  33       throw 1;
  34     CT::move(s1, s1+1, 2);
  35     if (s1[0] != char_type{1} || s1[1] != char_type{2} || s1[2] != char_type{2})
  36       throw 2;
  37
  38     // Disjoint strings
  39     char_type why_is_six_scared_of_seven[] = {4, 5, 6};
  40     char_type because789[] = {7, 8, 9};
  41     CT::move(why_is_six_scared_of_seven, because789, 3);
  42     if (why_is_six_scared_of_seven[0] != char_type{7}
  43         || why_is_six_scared_of_seven[1] != char_type{8}
  44         || why_is_six_scared_of_seven[2] != char_type{9})
  45       throw 3;
  46
  47     return true;
  48   }
  49
  50 #ifndef __cpp_lib_constexpr_string
  51 # error Feature-test macro for constexpr char_traits is missing
  52 #elif __cpp_lib_constexpr_string < 201811
  53 # error Feature-test macro for constexpr char_traits has the wrong value
  54 #endif
  55
  56 // We also provide this non-standard macro for P0426R1 and P1032R1.
  57 #ifndef __cpp_lib_constexpr_char_traits
  58 # error Feature-test macro for constexpr char_traits is missing
  59 #elif __cpp_lib_constexpr_char_traits != 201811
  60 # error Feature-test macro for constexpr char_traits has the wrong value
  61 #endif
  62
  63 static_assert( test_move<std::char_traits<char>>() );
  64 static_assert( test_move<std::char_traits<wchar_t>>() );
  65 #ifdef _GLIBCXX_USE_CHAR8_T
  66 static_assert( test_move<std::char_traits<char8_t>>() );
  67 #endif
  68 static_assert( test_move<std::char_traits<char16_t>>() );
  69 static_assert( test_move<std::char_traits<char32_t>>() );
  70
  71 struct C { unsigned char c; };
  72 constexpr bool operator==(const C& c1, const C& c2) { return c1.c == c2.c; }
  73 constexpr bool operator<(const C& c1, const C& c2) { return c1.c < c2.c; }
  74 static_assert( test_move<std::char_traits<C>>() );