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 // <shared_mutex> 11 12 // template <class Mutex> class shared_lock; 13 14 // explicit shared_lock(mutex_type& m); 15 16 #include <shared_mutex> 17 #include <thread> 18 #include <vector> 19 #include <cstdlib> 20 #include <cassert> 21 22 #if _LIBCPP_STD_VER > 11 23 24 std::shared_timed_mutex m; 25 26 typedef std::chrono::system_clock Clock; 27 typedef Clock::time_point time_point; 28 typedef Clock::duration duration; 29 typedef std::chrono::milliseconds ms; 30 typedef std::chrono::nanoseconds ns; 31 32 void f() 33 { 34 time_point t0 = Clock::now(); 35 time_point t1; 36 { 37 std::shared_lock<std::shared_timed_mutex> ul(m); 38 t1 = Clock::now(); 39 } 40 ns d = t1 - t0 - ms(250); 41 assert(d < ms(50)); // within 50ms 42 } 43 44 void g() 45 { 46 time_point t0 = Clock::now(); 47 time_point t1; 48 { 49 std::shared_lock<std::shared_timed_mutex> ul(m); 50 t1 = Clock::now(); 51 } 52 ns d = t1 - t0; 53 assert(d < ms(50)); // within 50ms 54 } 55 56 #endif // _LIBCPP_STD_VER > 11 57 58 int main() 59 { 60 #if _LIBCPP_STD_VER > 11 61 m.lock(); 62 std::vector<std::thread> v; 63 for (int i = 0; i < 5; ++i) 64 v.push_back(std::thread(f)); 65 std::this_thread::sleep_for(ms(250)); 66 m.unlock(); 67 for (auto& t : v) 68 t.join(); 69 m.lock_shared(); 70 for (auto& t : v) 71 t = std::thread(g); 72 std::thread q(f); 73 std::this_thread::sleep_for(ms(250)); 74 m.unlock_shared(); 75 for (auto& t : v) 76 t.join(); 77 q.join(); 78 #endif // _LIBCPP_STD_VER > 11 79 } 80
