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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_possible() const noexcept;
// Returns: false if:
// - *this does not have ownership of a stop state, or
// - a stop request was not made and there are no associated stop_source objects;
// otherwise, true.
#include <cassert>
#include <concepts>
#include <optional>
#include <stop_token>
#include <type_traits>
#include "make_test_thread.h"
#include "test_macros.h"
template <class T>
concept IsStopPossibleNoexcept = requires(const T& t) {
{ t.stop_possible() } noexcept;
};
static_assert(IsStopPossibleNoexcept<std::stop_token>);
int main(int, char**) {
// no state
{
const std::stop_token st;
assert(!st.stop_possible());
}
// a stop request was not made and there are no associated stop_source objects
{
std::optional<std::stop_source> ss{std::in_place};
const auto st = ss->get_token();
ss.reset();
assert(!st.stop_possible());
}
// a stop request was not made, but there is an associated stop_source objects
{
std::stop_source ss;
const auto st = ss.get_token();
assert(st.stop_possible());
}
// a stop request was made and there are no associated stop_source objects
{
std::optional<std::stop_source> ss{std::in_place};
const auto st = ss->get_token();
ss->request_stop();
ss.reset();
assert(st.stop_possible());
}
// a stop request was made and there is an associated stop_source objects
{
std::stop_source ss;
const auto st = ss.get_token();
ss.request_stop();
assert(st.stop_possible());
}
// a stop request was made on a different thread and
// there are no associated stop_source objects
{
std::optional<std::stop_source> ss{std::in_place};
const auto st = ss->get_token();
std::thread t = support::make_test_thread([&]() {
ss->request_stop();
ss.reset();
});
assert(st.stop_possible());
t.join();
assert(st.stop_possible());
}
return 0;
}
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