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

   1 // { dg-options "-std=gnu++2a" }
   2 // { dg-do compile { target c++2a } }
   3
   4 // Copyright (C) 2017-2021 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     char_type s1[3] = {1, 2, 3};
  29     CT::move(s1+1, s1, 2);
  30     return s1[0]==char_type{1} && s1[1]==char_type{1} && s1[2]==char_type{2};
  31   }
  32
  33 #ifndef __cpp_lib_constexpr_string
  34 # error Feature-test macro for constexpr char_traits is missing
  35 #elif __cpp_lib_constexpr_string < 201811
  36 # error Feature-test macro for constexpr char_traits has the wrong value
  37 #endif
  38
  39 // We also provide this non-standard macro for P0426R1 and P1032R1.
  40 #ifndef __cpp_lib_constexpr_char_traits
  41 # error Feature-test macro for constexpr char_traits is missing
  42 #elif __cpp_lib_constexpr_char_traits != 201811
  43 # error Feature-test macro for constexpr char_traits has the wrong value
  44 #endif
  45
  46 static_assert( test_move<std::char_traits<char>>() );
  47 static_assert( test_move<std::char_traits<wchar_t>>() );
  48 #ifdef _GLIBCXX_USE_CHAR8_T
  49 static_assert( test_move<std::char_traits<char8_t>>() );
  50 #endif
  51 static_assert( test_move<std::char_traits<char16_t>>() );
  52 static_assert( test_move<std::char_traits<char32_t>>() );
  53
  54 struct C { unsigned char c; };
  55 constexpr bool operator==(const C& c1, const C& c2) { return c1.c == c2.c; }
  56 constexpr bool operator<(const C& c1, const C& c2) { return c1.c < c2.c; }
  57 static_assert( test_move<std::char_traits<C>>() );