1//===----------------------------------------------------------------------===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is dual licensed under the MIT and the University of Illinois Open 6// Source Licenses. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9 10// <mutex> 11 12// template <class Mutex> class lock_guard; 13 14// lock_guard(mutex_type& m, adopt_lock_t); 15 16#include <mutex> 17#include <thread> 18#include <cstdlib> 19#include <cassert> 20 21std::mutex m; 22 23typedef std::chrono::system_clock Clock; 24typedef Clock::time_point time_point; 25typedef Clock::duration duration; 26typedef std::chrono::milliseconds ms; 27typedef std::chrono::nanoseconds ns; 28 29void f() 30{ 31 time_point t0 = Clock::now(); 32 time_point t1; 33 { 34 m.lock(); 35 std::lock_guard<std::mutex> lg(m, std::adopt_lock); 36 t1 = Clock::now(); 37 } 38 ns d = t1 - t0 - ms(250); 39 assert(d < ms(50)); // within 50ms 40} 41 42int main() 43{ 44 m.lock(); 45 std::thread t(f); 46 std::this_thread::sleep_for(ms(250)); 47 m.unlock(); 48 t.join(); 49} 50