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//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// UNSUPPORTED: no-threads
// UNSUPPORTED: libcpp-has-no-experimental-stop_token
// UNSUPPORTED: c++03, c++11, c++14, c++17
// XFAIL: availability-synchronization_library-missing
// [[nodiscard]] bool stop_requested() const noexcept;
// Returns: true if *this has ownership of a stop state that has received a stop request; otherwise, false.
#include <cassert>
#include <chrono>
#include <concepts>
#include <optional>
#include <stop_token>
#include <type_traits>
#include "make_test_thread.h"
#include "test_macros.h"
template <class T>
concept IsStopRequestedNoexcept = requires(const T& t) {
{ t.stop_requested() } noexcept;
};
static_assert(IsStopRequestedNoexcept<std::stop_token>);
int main(int, char**) {
// no state
{
const std::stop_token st;
assert(!st.stop_requested());
}
// has state
{
std::stop_source ss;
const auto st = ss.get_token();
assert(!st.stop_requested());
ss.request_stop();
assert(st.stop_requested());
}
// already requested before constructor
{
std::stop_source ss;
ss.request_stop();
const auto st = ss.get_token();
assert(st.stop_requested());
}
// stop_token should share the state
{
std::optional<std::stop_source> ss{std::in_place};
ss->request_stop();
const auto st = ss->get_token();
ss.reset();
assert(st.stop_requested());
}
// single stop_source, multiple stop_token
{
std::stop_source ss;
const auto st1 = ss.get_token();
const auto st2 = ss.get_token();
assert(!st1.stop_requested());
assert(!st2.stop_requested());
ss.request_stop();
assert(st1.stop_requested());
assert(st2.stop_requested());
}
// multiple stop_source, multiple stop_token
{
std::stop_source ss1;
std::stop_source ss2;
const auto st1 = ss1.get_token();
const auto st2 = ss2.get_token();
assert(!st1.stop_requested());
assert(!st2.stop_requested());
ss1.request_stop();
assert(st1.stop_requested());
assert(!st2.stop_requested());
}
// multiple threads
{
std::stop_source ss;
const auto st = ss.get_token();
assert(!st.stop_requested());
std::thread t = support::make_test_thread([&]() { ss.request_stop(); });
t.join();
assert(st.stop_requested());
}
// maybe concurrent calls
{
std::stop_source ss;
const auto st = ss.get_token();
assert(!st.stop_requested());
std::thread t = support::make_test_thread([&]() { ss.request_stop(); });
while (!st.stop_requested()) {
// should eventually exit the loop
std::this_thread::yield();
}
t.join();
}
// [thread.stoptoken.intro] A call to request_stop that returns true
// synchronizes with a call to stop_requested on an associated stop_token
// or stop_source object that returns true.
{
std::stop_source ss;
const auto st = ss.get_token();
assert(!st.stop_requested());
bool flag = false;
std::thread t = support::make_test_thread([&]() {
using namespace std::chrono_literals;
std::this_thread::sleep_for(1ms);
// happens-before request_stop
flag = true;
auto b = ss.request_stop();
assert(b);
});
while (!st.stop_requested()) {
std::this_thread::yield();
}
// write should be visible to the current thread
assert(flag == true);
t.join();
}
return 0;
}
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