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// Returns: 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_token>);
32
33int main(int, char**) {
34 // no state
35 {
36 const std::stop_token st;
37 assert(!st.stop_requested());
38 }
39
40 // has state
41 {
42 std::stop_source ss;
43 const auto st = ss.get_token();
44 assert(!st.stop_requested());
45
46 ss.request_stop();
47 assert(st.stop_requested());
48 }
49
50 // already requested before constructor
51 {
52 std::stop_source ss;
53 ss.request_stop();
54 const auto st = ss.get_token();
55 assert(st.stop_requested());
56 }
57
58 // stop_token should share the state
59 {
60 std::optional<std::stop_source> ss{std::in_place};
61 ss->request_stop();
62 const auto st = ss->get_token();
63
64 ss.reset();
65 assert(st.stop_requested());
66 }
67
68 // single stop_source, multiple stop_token
69 {
70 std::stop_source ss;
71 const auto st1 = ss.get_token();
72 const auto st2 = ss.get_token();
73 assert(!st1.stop_requested());
74 assert(!st2.stop_requested());
75
76 ss.request_stop();
77 assert(st1.stop_requested());
78 assert(st2.stop_requested());
79 }
80
81 // multiple stop_source, multiple stop_token
82 {
83 std::stop_source ss1;
84 std::stop_source ss2;
85
86 const auto st1 = ss1.get_token();
87 const auto st2 = ss2.get_token();
88 assert(!st1.stop_requested());
89 assert(!st2.stop_requested());
90
91 ss1.request_stop();
92 assert(st1.stop_requested());
93 assert(!st2.stop_requested());
94 }
95
96 // multiple threads
97 {
98 std::stop_source ss;
99 const auto st = ss.get_token();
100 assert(!st.stop_requested());
101
102 std::thread t = support::make_test_thread([&]() { ss.request_stop(); });
103
104 t.join();
105 assert(st.stop_requested());
106 }
107
108 // maybe concurrent calls
109 {
110 std::stop_source ss;
111 const auto st = ss.get_token();
112 assert(!st.stop_requested());
113
114 std::thread t = support::make_test_thread([&]() { ss.request_stop(); });
115
116 while (!st.stop_requested()) {
117 // should eventually exit the loop
118 std::this_thread::yield();
119 }
120
121 t.join();
122 }
123
124 // [thread.stoptoken.intro] A call to request_stop that returns true
125 // synchronizes with a call to stop_requested on an associated stop_token
126 // or stop_source object that returns true.
127 {
128 std::stop_source ss;
129 const auto st = ss.get_token();
130 assert(!st.stop_requested());
131
132 bool flag = false;
133
134 std::thread t = support::make_test_thread([&]() {
135 using namespace std::chrono_literals;
136 std::this_thread::sleep_for(1ms);
137
138 // happens-before request_stop
139 flag = true;
140 auto b = ss.request_stop();
141 assert(b);
142 });
143
144 while (!st.stop_requested()) {
145 std::this_thread::yield();
146 }
147
148 // write should be visible to the current thread
149 assert(flag == true);
150
151 t.join();
152 }
153
154 return 0;
155}
156

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