libstdc++-v3/testsuite/20_util/allocator/void.cc

   1 // Copyright (C) 2016-2021 Free Software Foundation, Inc.
   2 //
   3 // This file is part of the GNU ISO C++ Library.  This library is free
   4 // software; you can redistribute it and/or modify it under the
   5 // terms of the GNU General Public License as published by the
   6 // Free Software Foundation; either version 3, or (at your option)
   7 // any later version.
   8
   9 // This library is distributed in the hope that it will be useful,
  10 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 // GNU General Public License for more details.
  13
  14 // You should have received a copy of the GNU General Public License along
  15 // with this library; see the file COPYING3.  If not see
  16 // <http://www.gnu.org/licenses/>.
  17
  18 // { dg-do run { target c++11 } }
  19
  20 #include <memory>
  21 #include <testsuite_hooks.h>
  22
  23 template class std::allocator<void>;
  24
  25 void
  26 test01()
  27 {
  28   int i;
  29   using alloc_type = std::allocator<void>;
  30   alloc_type a;
  31   std::allocator_traits<alloc_type>::construct(a, &i, 42);
  32   VERIFY( i == 42 );
  33   std::allocator_traits<alloc_type>::destroy(a, &i);
  34 }
  35
  36 // These properties are formally unspecified, but have always been true for
  37 // the libstdc++ definition of allocator<void>.
  38 static_assert(
  39     std::is_trivially_default_constructible<std::allocator<void>>::value,
  40     "explicit specialization has trivial default constructor");
  41 static_assert(
  42     std::is_trivially_copy_constructible<std::allocator<void>>::value,
  43     "explicit specialization has trivial copy constructor");
  44 static_assert(
  45     std::is_trivially_move_constructible<std::allocator<void>>::value,
  46     "explicit specialization has trivial move constructor");
  47 static_assert(
  48     std::is_trivially_destructible<std::allocator<void>>::value,
  49     "explicit specialization has trivial destructor");
  50
  51 #if __cplusplus > 201703L
  52 // C++20 removes the allocator<void> explicit specialization, so it can now be
  53 // constructed using the converting constructor from other specializations.
  54 static_assert( std::is_constructible_v<std::allocator<void>,
  55                                        std::allocator<int>> );
  56 #endif
  57
  58 int
  59 main()
  60 {
  61   test01();
  62 }