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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;
// 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_source>);
int main(int, char**) {
// no state
{
const std::stop_source ss{std::nostopstate};
assert(!ss.stop_requested());
}
// has state
{
std::stop_source ss;
assert(!ss.stop_requested());
ss.request_stop();
assert(ss.stop_requested());
}
// request from another instance with same state
{
std::stop_source ss1;
auto ss2 = ss1;
ss2.request_stop();
assert(ss1.stop_requested());
}
// request from another instance with different state
{
std::stop_source ss1;
std::stop_source ss2;
ss2.request_stop();
assert(!ss1.stop_requested());
}
// multiple threads
{
std::stop_source ss;
std::thread t = support::make_test_thread([&]() { ss.request_stop(); });
t.join();
assert(ss.stop_requested());
}
// [thread.stopsource.intro] A call to request_stop that returns true
// synchronizes with a call to stop_requested on an associated stop_source
// or stop_source object that returns true.
{
std::stop_source ss;
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 (!ss.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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