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 // <shared_mutex> 13 14 // template <class Mutex> class shared_lock; 15 16 // explicit shared_lock(mutex_type& m); 17 18 #include <shared_mutex> 19 #include <thread> 20 #include <vector> 21 #include <cstdlib> 22 #include <cassert> 23 24 #if _LIBCPP_STD_VER > 11 25 26 std::shared_timed_mutex m; 27 28 typedef std::chrono::system_clock Clock; 29 typedef Clock::time_point time_point; 30 typedef Clock::duration duration; 31 typedef std::chrono::milliseconds ms; 32 typedef std::chrono::nanoseconds ns; 33 34 void f() 35 { 36 time_point t0 = Clock::now(); 37 time_point t1; 38 { 39 std::shared_lock<std::shared_timed_mutex> ul(m); 40 t1 = Clock::now(); 41 } 42 ns d = t1 - t0 - ms(250); 43 assert(d < ms(50)); // within 50ms 44 } 45 46 void g() 47 { 48 time_point t0 = Clock::now(); 49 time_point t1; 50 { 51 std::shared_lock<std::shared_timed_mutex> ul(m); 52 t1 = Clock::now(); 53 } 54 ns d = t1 - t0; 55 assert(d < ms(50)); // within 50ms 56 } 57 58 #endif // _LIBCPP_STD_VER > 11 59 60 int main() 61 { 62 #if _LIBCPP_STD_VER > 11 63 m.lock(); 64 std::vector<std::thread> v; 65 for (int i = 0; i < 5; ++i) 66 v.push_back(std::thread(f)); 67 std::this_thread::sleep_for(ms(250)); 68 m.unlock(); 69 for (auto& t : v) 70 t.join(); 71 m.lock_shared(); 72 for (auto& t : v) 73 t = std::thread(g); 74 std::thread q(f); 75 std::this_thread::sleep_for(ms(250)); 76 m.unlock_shared(); 77 for (auto& t : v) 78 t.join(); 79 q.join(); 80 #endif // _LIBCPP_STD_VER > 11 81 } 82
