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 // UNSUPPORTED: libcpp-has-no-threads 11 12 // <mutex> 13 14 // template <class Mutex> class lock_guard; 15 16 // explicit lock_guard(mutex_type& m); 17 18 // template<class _Mutex> lock_guard(lock_guard<_Mutex>) 19 // -> lock_guard<_Mutex>; // C++17 20 21 #include <mutex> 22 #include <thread> 23 #include <cstdlib> 24 #include <cassert> 25 26 #include "test_macros.h" 27 28 std::mutex m; 29 30 typedef std::chrono::system_clock Clock; 31 typedef Clock::time_point time_point; 32 typedef Clock::duration duration; 33 typedef std::chrono::milliseconds ms; 34 typedef std::chrono::nanoseconds ns; 35 36 void f() 37 { 38 time_point t0 = Clock::now(); 39 time_point t1; 40 { 41 std::lock_guard<std::mutex> lg(m); 42 t1 = Clock::now(); 43 } 44 ns d = t1 - t0 - ms(250); 45 assert(d < ms(200)); // within 200ms 46 } 47 48 int main() 49 { 50 m.lock(); 51 std::thread t(f); 52 std::this_thread::sleep_for(ms(250)); 53 m.unlock(); 54 t.join(); 55 56 #ifdef __cpp_deduction_guides 57 std::lock_guard lg(m); 58 static_assert((std::is_same<decltype(lg), std::lock_guard<decltype(m)>>::value), "" ); 59 #endif 60 } 61
