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 // shared_lock(mutex_type& m, try_to_lock_t); 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 { 36 std::shared_lock<std::shared_timed_mutex> lk(m, std::try_to_lock); 37 assert(lk.owns_lock() == false); 38 } 39 { 40 std::shared_lock<std::shared_timed_mutex> lk(m, std::try_to_lock); 41 assert(lk.owns_lock() == false); 42 } 43 { 44 std::shared_lock<std::shared_timed_mutex> lk(m, std::try_to_lock); 45 assert(lk.owns_lock() == false); 46 } 47 while (true) 48 { 49 std::shared_lock<std::shared_timed_mutex> lk(m, std::try_to_lock); 50 if (lk.owns_lock()) 51 break; 52 } 53 time_point t1 = Clock::now(); 54 ns d = t1 - t0 - ms(250); 55 assert(d < ms(200)); // within 200ms 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 #endif // _LIBCPP_STD_VER > 11 72 } 73
