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 // shared_lock(mutex_type& m, try_to_lock_t); 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 { 38 std::shared_lock<std::shared_timed_mutex> lk(m, std::try_to_lock); 39 assert(lk.owns_lock() == false); 40 } 41 { 42 std::shared_lock<std::shared_timed_mutex> lk(m, std::try_to_lock); 43 assert(lk.owns_lock() == false); 44 } 45 { 46 std::shared_lock<std::shared_timed_mutex> lk(m, std::try_to_lock); 47 assert(lk.owns_lock() == false); 48 } 49 while (true) 50 { 51 std::shared_lock<std::shared_timed_mutex> lk(m, std::try_to_lock); 52 if (lk.owns_lock()) 53 break; 54 } 55 time_point t1 = Clock::now(); 56 ns d = t1 - t0 - ms(250); 57 assert(d < ms(200)); // within 200ms 58 } 59 60 #endif // _LIBCPP_STD_VER > 11 61 62 int main() 63 { 64 #if _LIBCPP_STD_VER > 11 65 m.lock(); 66 std::vector<std::thread> v; 67 for (int i = 0; i < 5; ++i) 68 v.push_back(std::thread(f)); 69 std::this_thread::sleep_for(ms(250)); 70 m.unlock(); 71 for (auto& t : v) 72 t.join(); 73 #endif // _LIBCPP_STD_VER > 11 74 } 75
