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++98, 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 "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 deallocate(void*, unsigned) {} 38 39 typedef std::true_type propagate_on_container_swap; 40 }; 41 42 template <class T> 43 struct some_alloc2 44 { 45 typedef T value_type; 46 47 some_alloc2() {} 48 some_alloc2(const some_alloc2&); 49 void deallocate(void*, unsigned) {} 50 51 typedef std::false_type propagate_on_container_swap; 52 typedef std::true_type is_always_equal; 53 }; 54 55 int main() 56 { 57 #if defined(_LIBCPP_VERSION) 58 { 59 typedef std::vector<bool> C; 60 static_assert(noexcept(swap(std::declval<C&>(), std::declval<C&>())), ""); 61 } 62 { 63 typedef std::vector<bool, test_allocator<bool>> C; 64 static_assert(noexcept(swap(std::declval<C&>(), std::declval<C&>())), ""); 65 } 66 { 67 typedef std::vector<bool, other_allocator<bool>> C; 68 static_assert(noexcept(swap(std::declval<C&>(), std::declval<C&>())), ""); 69 } 70 #endif // _LIBCPP_VERSION 71 { 72 #if TEST_STD_VER >= 14 73 #if defined(_LIBCPP_VERSION) 74 // In C++14, if POCS is set, swapping the allocator is required not to throw 75 typedef std::vector<bool, some_alloc<bool>> C; 76 static_assert( noexcept(swap(std::declval<C&>(), std::declval<C&>())), ""); 77 #endif // _LIBCPP_VERSION 78 #else 79 typedef std::vector<bool, some_alloc<bool>> C; 80 static_assert(!noexcept(swap(std::declval<C&>(), std::declval<C&>())), ""); 81 #endif 82 } 83 #if TEST_STD_VER >= 14 84 #if defined(_LIBCPP_VERSION) 85 { 86 typedef std::vector<bool, some_alloc2<bool>> C; 87 // if the allocators are always equal, then the swap can be noexcept 88 static_assert( noexcept(swap(std::declval<C&>(), std::declval<C&>())), ""); 89 } 90 #endif // _LIBCPP_VERSION 91 #endif 92 } 93