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 recursive_mutex; 13 14 // bool try_lock(); 15 16 #include <mutex> 17 #include <thread> 18 #include <cstdlib> 19 #include <cassert> 20 21 std::recursive_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 assert(m.try_lock()); 39 m.unlock(); 40 m.unlock(); 41 ns d = t1 - t0 - ms(250); 42 assert(d < ns(50000000)); // within 50ms 43 } 44 45 int main() 46 { 47 m.lock(); 48 std::thread t(f); 49 std::this_thread::sleep_for(ms(250)); 50 m.unlock(); 51 t.join(); 52 } 53
