xref: /llvm-project/libcxx/test/std/atomics/atomics.ref/assign.pass.cpp (revision 2e43a304f10fd801f068d0f9831f01f2c5b0b2e2)
1 //
2 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
3 // See https://llvm.org/LICENSE.txt for license information.
4 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
5 //
6 //===----------------------------------------------------------------------===//
7 
8 // UNSUPPORTED: c++03, c++11, c++14, c++17
9 // XFAIL: !has-64-bit-atomics
10 // XFAIL: !has-1024-bit-atomics
11 
12 // T operator=(T) const noexcept;
13 
14 #include <atomic>
15 #include <cassert>
16 #include <concepts>
17 #include <type_traits>
18 
19 #include "atomic_helpers.h"
20 #include "test_helper.h"
21 #include "test_macros.h"
22 
23 template <typename T>
24 struct TestAssign {
25   void operator()() const {
26     {
27       T x(T(1));
28       std::atomic_ref<T> const a(x);
29 
30       std::same_as<T> decltype(auto) y = (a = T(2));
31       assert(y == T(2));
32       assert(x == T(2));
33 
34       ASSERT_NOEXCEPT(a = T(0));
35       static_assert(std::is_nothrow_assignable_v<std::atomic_ref<T>, T>);
36 
37       static_assert(!std::is_copy_assignable_v<std::atomic_ref<T>>);
38     }
39 
40     {
41       auto assign = [](std::atomic_ref<T> const& y, T, T new_val) { y = new_val; };
42       auto load   = [](std::atomic_ref<T> const& y) { return y.load(); };
43       test_seq_cst<T>(assign, load);
44     }
45   }
46 };
47 
48 int main(int, char**) {
49   TestEachAtomicType<TestAssign>()();
50   return 0;
51 }
52