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: libcpp-has-no-threads
10 
11 // <atomic>
12 
13 // struct atomic_flag
14 
15 // void atomic_flag_clear_explicit(volatile atomic_flag*, memory_order);
16 // void atomic_flag_clear_explicit(atomic_flag*, memory_order);
17 
18 #include <atomic>
19 #include <cassert>
20 
21 int main(int, char**)
22 {
23     {
24         std::atomic_flag f; // uninitialized first
25         atomic_flag_clear_explicit(&f, std::memory_order_relaxed);
26         assert(f.test_and_set() == 0);
27         atomic_flag_clear_explicit(&f, std::memory_order_relaxed);
28         assert(f.test_and_set() == 0);
29     }
30     {
31         std::atomic_flag f;
32         atomic_flag_clear_explicit(&f, std::memory_order_release);
33         assert(f.test_and_set() == 0);
34         atomic_flag_clear_explicit(&f, std::memory_order_release);
35         assert(f.test_and_set() == 0);
36     }
37     {
38         std::atomic_flag f;
39         atomic_flag_clear_explicit(&f, std::memory_order_seq_cst);
40         assert(f.test_and_set() == 0);
41         atomic_flag_clear_explicit(&f, std::memory_order_seq_cst);
42         assert(f.test_and_set() == 0);
43     }
44     {
45         volatile std::atomic_flag f;
46         atomic_flag_clear_explicit(&f, std::memory_order_relaxed);
47         assert(f.test_and_set() == 0);
48         atomic_flag_clear_explicit(&f, std::memory_order_relaxed);
49         assert(f.test_and_set() == 0);
50     }
51     {
52         volatile std::atomic_flag f;
53         atomic_flag_clear_explicit(&f, std::memory_order_release);
54         assert(f.test_and_set() == 0);
55         atomic_flag_clear_explicit(&f, std::memory_order_release);
56         assert(f.test_and_set() == 0);
57     }
58     {
59         volatile std::atomic_flag f;
60         atomic_flag_clear_explicit(&f, std::memory_order_seq_cst);
61         assert(f.test_and_set() == 0);
62         atomic_flag_clear_explicit(&f, std::memory_order_seq_cst);
63         assert(f.test_and_set() == 0);
64     }
65 
66   return 0;
67 }
68