libstdc++-v3/testsuite/20_util/allocator_traits/members/pointers.cc

   1 // Copyright (C) 2017-2020 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 compile { target c++11 } }
  19
  20 #include <memory>
  21
  22 // Non-type template param means pointer_traits::rebind can't be instantiated.
  23 template<typename T, int = 0>
  24   struct Pointer
  25   {
  26     using element_type = T;
  27     Pointer(T* p = nullptr) : ptr(p) { }
  28     T* ptr;
  29   };
  30
  31 template<typename T>
  32   struct Alloc
  33   {
  34     using value_type = T;
  35     using pointer = Pointer<T>;
  36     using const_pointer = Pointer<const T>;
  37     using void_pointer = Pointer<void>;
  38     using const_void_pointer = Pointer<const void>;
  39
  40     pointer allocate(std::size_t n)
  41     { return std::allocator<T>().allocate(n); }
  42
  43     void allocate(pointer p, std::size_t n)
  44     { return std::allocator<T>().deallocate(p, n); }
  45   };
  46
  47 // The nested pointer types in Alloc should be found without attempting to
  48 // instantiate pointer_traits::rebind (which would fail):
  49 std::allocator_traits<Alloc<int>>::pointer p;
  50 std::allocator_traits<Alloc<int>>::const_pointer cp;
  51 std::allocator_traits<Alloc<int>>::void_pointer vp;
  52 std::allocator_traits<Alloc<int>>::const_void_pointer cvp;