libcxx/test/std/containers/sequences/vector/vector.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 // <vector>
  12
  13 // void swap(vector& 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>::propagate_on_container_swap::value ||
  19 //              allocator_traits<Allocator>::is_always_equal::value);
  20
  21 // This tests a conforming extension
  22
  23 #include <vector>
  24 #include <utility>
  25 #include <cassert>
  26
  27 #include "test_macros.h"
  28 #include "MoveOnly.h"
  29 #include "test_allocator.h"
  30
  31 template <class T>
  32 struct some_alloc
  33 {
  34     typedef T value_type;
  35
  36     some_alloc() {}
  37     some_alloc(const some_alloc&);
  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 deallocate(void*, unsigned) {}
  51
  52     typedef std::false_type propagate_on_container_swap;
  53     typedef std::true_type is_always_equal;
  54 };
  55
  56 int main(int, char**)
  57 {
  58     {
  59         typedef std::vector<MoveOnly> C;
  60         static_assert(noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
  61     }
  62 #if defined(_LIBCPP_VERSION)
  63     {
  64         typedef std::vector<MoveOnly, test_allocator<MoveOnly>> C;
  65         static_assert(noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
  66     }
  67 #endif // _LIBCPP_VERSION
  68     {
  69         typedef std::vector<MoveOnly, other_allocator<MoveOnly>> C;
  70         static_assert(noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
  71     }
  72     {
  73         typedef std::vector<MoveOnly, some_alloc<MoveOnly>> C;
  74 #if TEST_STD_VER >= 14
  75     //  In C++14, if POCS is set, swapping the allocator is required not to throw
  76         static_assert( noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
  77 #else
  78         static_assert(!noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
  79 #endif
  80     }
  81 #if TEST_STD_VER >= 14
  82     {
  83         typedef std::vector<MoveOnly, some_alloc2<MoveOnly>> C;
  84     //  if the allocators are always equal, then the swap can be noexcept
  85         static_assert( noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
  86     }
  87 #endif
  88
  89   return 0;
  90 }