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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: libcpp-has-no-threads
// UNSUPPORTED: c++03, c++11
// dylib support for shared_mutex was added in macosx10.12
// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11}}
// <shared_mutex>
// class timed_mutex;
// template <class Rep, class Period>
// shared_lock(mutex_type& m, const chrono::duration<Rep, Period>& rel_time);
#include <thread>
#include <atomic>
#include <cassert>
#include <cstdlib>
#include <shared_mutex>
#include <vector>
#include "make_test_thread.h"
#include "test_macros.h"
std::shared_timed_mutex m;
typedef std::chrono::steady_clock Clock;
typedef Clock::time_point time_point;
typedef Clock::duration duration;
typedef std::chrono::milliseconds ms;
typedef std::chrono::nanoseconds ns;
ms LongTime = ms(5000);
ms ShortTime = ms(50);
static const unsigned Threads = 5;
std::atomic<unsigned> CountDown(Threads);
void f1()
{
// Preemptive scheduling means that one cannot make assumptions about when
// code executes and therefore we cannot assume anthing about when the mutex
// starts waiting relative to code in the main thread. We can however prove
// that a timeout occured and that implies that this code is waiting.
// See f2() below.
//
// Nevertheless, we should at least try to ensure that the mutex waits and
// therefore we use an atomic variable to signal to the main thread that this
// code is just a few instructions away from waiting.
--CountDown;
std::shared_lock<std::shared_timed_mutex> lk(m, LongTime);
assert(lk.owns_lock() == true);
}
void f2()
{
time_point t0 = Clock::now();
std::shared_lock<std::shared_timed_mutex> lk(m, ShortTime);
time_point t1 = Clock::now();
assert(lk.owns_lock() == false);
assert(t1 - t0 >= ShortTime);
}
int main(int, char**)
{
{
m.lock();
std::vector<std::thread> v;
for (unsigned i = 0; i < Threads; ++i)
v.push_back(support::make_test_thread(f1));
while (CountDown > 0)
std::this_thread::yield();
// Give one more chance for threads to block and wait for the mutex.
std::this_thread::yield();
std::this_thread::sleep_for(ShortTime);
m.unlock();
for (auto& t : v)
t.join();
}
{
m.lock();
std::vector<std::thread> v;
for (unsigned i = 0; i < Threads; ++i)
v.push_back(support::make_test_thread(f2));
for (auto& t : v)
t.join();
m.unlock();
}
return 0;
}
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