forked from OSchip/llvm-project
50 lines
1.1 KiB
C++
50 lines
1.1 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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// <mutex>
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// template <class Mutex> class lock_guard;
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// lock_guard(mutex_type& m, adopt_lock_t);
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#include <mutex>
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#include <thread>
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#include <cstdlib>
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#include <cassert>
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std::mutex m;
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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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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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m.lock();
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std::lock_guard<std::mutex> lg(m, std::adopt_lock);
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t1 = Clock::now();
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}
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ns d = t1 - t0 - ms(250);
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assert(d < ns(2500000)); // within 2.5ms
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}
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int main()
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{
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m.lock();
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std::thread t(f);
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std::this_thread::sleep_for(ms(250));
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m.unlock();
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t.join();
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}
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