//===----------------------------------------------------------------------===// | |
// | |
// The LLVM Compiler Infrastructure | |
// | |
// This file is dual licensed under the MIT and the University of Illinois Open | |
// Source Licenses. See LICENSE.TXT for details. | |
// | |
//===----------------------------------------------------------------------===// | |
// | |
// UNSUPPORTED: libcpp-has-no-threads | |
// UNSUPPORTED: c++98, c++03 | |
// <future> | |
// class shared_future<R> | |
// template <class Clock, class Duration> | |
// future_status | |
// wait_until(const chrono::time_point<Clock, Duration>& abs_time) const; | |
#include <future> | |
#include <atomic> | |
#include <cassert> | |
enum class WorkerThreadState { Uninitialized, AllowedToRun, Exiting }; | |
typedef std::chrono::milliseconds ms; | |
std::atomic<WorkerThreadState> thread_state(WorkerThreadState::Uninitialized); | |
void set_worker_thread_state(WorkerThreadState state) | |
{ | |
thread_state.store(state, std::memory_order_relaxed); | |
} | |
void wait_for_worker_thread_state(WorkerThreadState state) | |
{ | |
while (thread_state.load(std::memory_order_relaxed) != state); | |
} | |
void func1(std::promise<int> p) | |
{ | |
wait_for_worker_thread_state(WorkerThreadState::AllowedToRun); | |
p.set_value(3); | |
set_worker_thread_state(WorkerThreadState::Exiting); | |
} | |
int j = 0; | |
void func3(std::promise<int&> p) | |
{ | |
wait_for_worker_thread_state(WorkerThreadState::AllowedToRun); | |
j = 5; | |
p.set_value(j); | |
set_worker_thread_state(WorkerThreadState::Exiting); | |
} | |
void func5(std::promise<void> p) | |
{ | |
wait_for_worker_thread_state(WorkerThreadState::AllowedToRun); | |
p.set_value(); | |
set_worker_thread_state(WorkerThreadState::Exiting); | |
} | |
int main() | |
{ | |
typedef std::chrono::high_resolution_clock Clock; | |
{ | |
typedef int T; | |
std::promise<T> p; | |
std::shared_future<T> f = p.get_future(); | |
std::thread(func1, std::move(p)).detach(); | |
assert(f.valid()); | |
assert(f.wait_until(Clock::now() + ms(10)) == std::future_status::timeout); | |
assert(f.valid()); | |
// allow the worker thread to produce the result and wait until the worker is done | |
set_worker_thread_state(WorkerThreadState::AllowedToRun); | |
wait_for_worker_thread_state(WorkerThreadState::Exiting); | |
assert(f.wait_until(Clock::now() + ms(10)) == std::future_status::ready); | |
assert(f.valid()); | |
Clock::time_point t0 = Clock::now(); | |
f.wait(); | |
Clock::time_point t1 = Clock::now(); | |
assert(f.valid()); | |
assert(t1-t0 < ms(5)); | |
} | |
{ | |
typedef int& T; | |
std::promise<T> p; | |
std::shared_future<T> f = p.get_future(); | |
std::thread(func3, std::move(p)).detach(); | |
assert(f.valid()); | |
assert(f.wait_until(Clock::now() + ms(10)) == std::future_status::timeout); | |
assert(f.valid()); | |
// allow the worker thread to produce the result and wait until the worker is done | |
set_worker_thread_state(WorkerThreadState::AllowedToRun); | |
wait_for_worker_thread_state(WorkerThreadState::Exiting); | |
assert(f.wait_until(Clock::now() + ms(10)) == std::future_status::ready); | |
assert(f.valid()); | |
Clock::time_point t0 = Clock::now(); | |
f.wait(); | |
Clock::time_point t1 = Clock::now(); | |
assert(f.valid()); | |
assert(t1-t0 < ms(5)); | |
} | |
{ | |
typedef void T; | |
std::promise<T> p; | |
std::shared_future<T> f = p.get_future(); | |
std::thread(func5, std::move(p)).detach(); | |
assert(f.valid()); | |
assert(f.wait_until(Clock::now() + ms(10)) == std::future_status::timeout); | |
assert(f.valid()); | |
// allow the worker thread to produce the result and wait until the worker is done | |
set_worker_thread_state(WorkerThreadState::AllowedToRun); | |
wait_for_worker_thread_state(WorkerThreadState::Exiting); | |
assert(f.wait_until(Clock::now() + ms(10)) == std::future_status::ready); | |
assert(f.valid()); | |
Clock::time_point t0 = Clock::now(); | |
f.wait(); | |
Clock::time_point t1 = Clock::now(); | |
assert(f.valid()); | |
assert(t1-t0 < ms(5)); | |
} | |
} |