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: no-threads
10// UNSUPPORTED: c++03, c++11, c++14, c++17
11// XFAIL: availability-synchronization_library-missing
12
13// [[nodiscard]] bool stop_requested() const noexcept;
14// true if *this has ownership of a stop state that has received a stop request; otherwise, false.
15
16#include <cassert>
17#include <chrono>
18#include <concepts>
19#include <optional>
20#include <stop_token>
21#include <type_traits>
22
23#include "make_test_thread.h"
24#include "test_macros.h"
25
26template <class T>
27concept IsStopRequestedNoexcept = requires(const T& t) {
28 { t.stop_requested() } noexcept;
29};
30
31static_assert(IsStopRequestedNoexcept<std::stop_source>);
32
33int main(int, char**) {
34 // no state
35 {
36 const std::stop_source ss{std::nostopstate};
37 assert(!ss.stop_requested());
38 }
39
40 // has state
41 {
42 std::stop_source ss;
43 assert(!ss.stop_requested());
44
45 ss.request_stop();
46 assert(ss.stop_requested());
47 }
48
49 // request from another instance with same state
50 {
51 std::stop_source ss1;
52 auto ss2 = ss1;
53 ss2.request_stop();
54 assert(ss1.stop_requested());
55 }
56
57 // request from another instance with different state
58 {
59 std::stop_source ss1;
60 std::stop_source ss2;
61
62 ss2.request_stop();
63 assert(!ss1.stop_requested());
64 }
65
66 // multiple threads
67 {
68 std::stop_source ss;
69
70 std::thread t = support::make_test_thread([&]() { ss.request_stop(); });
71
72 t.join();
73 assert(ss.stop_requested());
74 }
75
76 // [thread.stopsource.intro] A call to request_stop that returns true
77 // synchronizes with a call to stop_requested on an associated stop_source
78 // or stop_source object that returns true.
79 {
80 std::stop_source ss;
81
82 bool flag = false;
83
84 std::thread t = support::make_test_thread([&]() {
85 using namespace std::chrono_literals;
86 std::this_thread::sleep_for(1ms);
87
88 // happens-before request_stop
89 flag = true;
90 auto b = ss.request_stop();
91 assert(b);
92 });
93
94 while (!ss.stop_requested()) {
95 std::this_thread::yield();
96 }
97
98 // write should be visible to the current thread
99 assert(flag == true);
100
101 t.join();
102 }
103
104 return 0;
105}
106

source code of libcxx/test/std/thread/thread.stoptoken/stopsource/stop_requested.pass.cpp