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_possible() const noexcept;
14// Returns: false if:
15// - *this does not have ownership of a stop state, or
16// - a stop request was not made and there are no associated stop_source objects;
17// otherwise, true.
18
19#include <cassert>
20#include <concepts>
21#include <optional>
22#include <stop_token>
23#include <type_traits>
24
25#include "make_test_thread.h"
26#include "test_macros.h"
27
28template <class T>
29concept IsStopPossibleNoexcept = requires(const T& t) {
30 { t.stop_possible() } noexcept;
31};
32
33static_assert(IsStopPossibleNoexcept<std::stop_token>);
34
35int main(int, char**) {
36 // no state
37 {
38 const std::stop_token st;
39 assert(!st.stop_possible());
40 }
41
42 // a stop request was not made and there are no associated stop_source objects
43 {
44 std::optional<std::stop_source> ss{std::in_place};
45 const auto st = ss->get_token();
46 ss.reset();
47
48 assert(!st.stop_possible());
49 }
50
51 // a stop request was not made, but there is an associated stop_source objects
52 {
53 std::stop_source ss;
54 const auto st = ss.get_token();
55 assert(st.stop_possible());
56 }
57
58 // a stop request was made and there are no associated stop_source objects
59 {
60 std::optional<std::stop_source> ss{std::in_place};
61 const auto st = ss->get_token();
62 ss->request_stop();
63 ss.reset();
64
65 assert(st.stop_possible());
66 }
67
68 // a stop request was made and there is an associated stop_source objects
69 {
70 std::stop_source ss;
71 const auto st = ss.get_token();
72 ss.request_stop();
73 assert(st.stop_possible());
74 }
75
76 // a stop request was made on a different thread and
77 // there are no associated stop_source objects
78 {
79 std::optional<std::stop_source> ss{std::in_place};
80 const auto st = ss->get_token();
81
82 std::thread t = support::make_test_thread([&]() {
83 ss->request_stop();
84 ss.reset();
85 });
86
87 assert(st.stop_possible());
88 t.join();
89 assert(st.stop_possible());
90
91 }
92
93 return 0;
94}
95

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