libcxx/test/std/containers/sequences/list/list.special/swap_noexcept.pass.cpp

   1 //===----------------------------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 // UNSUPPORTED: c++03
  10
  11 // <list>
  12
  13 // void swap(list& c)
  14 //     noexcept(!allocator_type::propagate_on_container_swap::value ||
  15 //              __is_nothrow_swappable<allocator_type>::value);
  16 //
  17 //  In C++17, the standard says that swap shall have:
  18 //     noexcept(allocator_traits<Allocator>::is_always_equal::value);
  19
  20 // This tests a conforming extension
  21
  22 #include <list>
  23 #include <utility>
  24 #include <cassert>
  25
  26 #include "test_macros.h"
  27 #include "MoveOnly.h"
  28 #include "test_allocator.h"
  29
  30 template <class T>
  31 struct some_alloc
  32 {
  33     typedef T value_type;
  34
  35     some_alloc() {}
  36     some_alloc(const some_alloc&);
  37     void allocate(std::size_t);
  38     void deallocate(void*, unsigned) {}
  39
  40     typedef std::true_type propagate_on_container_swap;
  41 };
  42
  43 template <class T>
  44 struct some_alloc2
  45 {
  46     typedef T value_type;
  47
  48     some_alloc2() {}
  49     some_alloc2(const some_alloc2&);
  50     void allocate(std::size_t);
  51     void deallocate(void*, unsigned) {}
  52
  53     typedef std::false_type propagate_on_container_swap;
  54     typedef std::true_type is_always_equal;
  55 };
  56
  57 int main(int, char**)
  58 {
  59     {
  60         typedef std::list<MoveOnly> C;
  61         static_assert(noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
  62     }
  63 #if defined(_LIBCPP_VERSION)
  64     {
  65         typedef std::list<MoveOnly, test_allocator<MoveOnly>> C;
  66         static_assert(noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
  67     }
  68     {
  69         typedef std::list<MoveOnly, other_allocator<MoveOnly>> C;
  70         static_assert(noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
  71     }
  72 #endif // _LIBCPP_VERSION
  73     {
  74         typedef std::list<MoveOnly, some_alloc<MoveOnly>> C;
  75 #if TEST_STD_VER >= 14
  76     //  In C++14, if POCS is set, swapping the allocator is required not to throw
  77         static_assert( noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
  78 #else
  79         static_assert(!noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
  80 #endif
  81     }
  82 #if TEST_STD_VER >= 14
  83     {
  84         typedef std::list<MoveOnly, some_alloc2<MoveOnly>> C;
  85     //  if the allocators are always equal, then the swap can be noexcept
  86         static_assert( noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
  87     }
  88 #endif
  89
  90
  91   return 0;
  92 }