forked from OSchip/llvm-project
96 lines
2.1 KiB
C++
96 lines
2.1 KiB
C++
//===----------------------------------------------------------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is dual licensed under the MIT and the University of Illinois Open
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// Source Licenses. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// UNSUPPORTED: libcpp-has-no-threads
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// UNSUPPORTED: c++98, c++03, c++11
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// FLAKY_TEST
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// <shared_mutex>
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// template <class Mutex> class shared_lock;
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// explicit shared_lock(mutex_type& m);
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#include <shared_mutex>
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#include <thread>
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#include <vector>
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#include <cstdlib>
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#include <cassert>
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#include "test_macros.h"
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typedef std::chrono::system_clock Clock;
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typedef Clock::time_point time_point;
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typedef Clock::duration duration;
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typedef std::chrono::milliseconds ms;
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typedef std::chrono::nanoseconds ns;
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ms WaitTime = ms(250);
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// Thread sanitizer causes more overhead and will sometimes cause this test
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// to fail. To prevent this we give Thread sanitizer more time to complete the
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// test.
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#if !defined(TEST_HAS_SANITIZERS)
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ms Tolerance = ms(50);
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#else
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ms Tolerance = ms(50 * 5);
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#endif
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std::shared_timed_mutex m;
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void f()
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{
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time_point t0 = Clock::now();
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time_point t1;
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{
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std::shared_lock<std::shared_timed_mutex> ul(m);
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t1 = Clock::now();
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}
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ns d = t1 - t0 - WaitTime;
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assert(d < Tolerance); // within tolerance
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}
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void g()
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{
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time_point t0 = Clock::now();
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time_point t1;
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{
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std::shared_lock<std::shared_timed_mutex> ul(m);
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t1 = Clock::now();
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}
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ns d = t1 - t0;
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assert(d < Tolerance); // within tolerance
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}
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int main()
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{
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std::vector<std::thread> v;
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{
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m.lock();
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for (int i = 0; i < 5; ++i)
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v.push_back(std::thread(f));
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std::this_thread::sleep_for(WaitTime);
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m.unlock();
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for (auto& t : v)
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t.join();
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}
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{
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m.lock_shared();
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for (auto& t : v)
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t = std::thread(g);
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std::thread q(f);
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std::this_thread::sleep_for(WaitTime);
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m.unlock_shared();
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for (auto& t : v)
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t.join();
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q.join();
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}
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}
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