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 // class mutex; 13 14 // bool try_lock(); 15 16 #include <mutex> 17 #include <thread> 18 #include <cstdlib> 19 #include <cassert> 20 21 std::mutex m; 22 23 typedef std::chrono::system_clock Clock; 24 typedef Clock::time_point time_point; 25 typedef Clock::duration duration; 26 typedef std::chrono::milliseconds ms; 27 typedef std::chrono::nanoseconds ns; 28 29 void f() 30 { 31 time_point t0 = Clock::now(); 32 assert(!m.try_lock()); 33 assert(!m.try_lock()); 34 assert(!m.try_lock()); 35 while(!m.try_lock()) 36 ; 37 time_point t1 = Clock::now(); 38 m.unlock(); 39 ns d = t1 - t0 - ms(250); 40 assert(d < ns(50000000)); // within 50ms 41 } 42 43 int main() 44 { 45 m.lock(); 46 std::thread t(f); 47 std::this_thread::sleep_for(ms(250)); 48 m.unlock(); 49 t.join(); 50 } 51
