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 // UNSUPPORTED: c++03, c++98, c++11, c++14 12 13 // <shared_mutex> 14 15 // class shared_mutex; 16 17 // bool try_lock_shared(); 18 19 #include <shared_mutex> 20 #include <thread> 21 #include <vector> 22 #include <cstdlib> 23 #include <cassert> 24 25 std::shared_mutex m; 26 27 typedef std::chrono::system_clock Clock; 28 typedef Clock::time_point time_point; 29 typedef Clock::duration duration; 30 typedef std::chrono::milliseconds ms; 31 typedef std::chrono::nanoseconds ns; 32 33 void f() 34 { 35 time_point t0 = Clock::now(); 36 assert(!m.try_lock_shared()); 37 assert(!m.try_lock_shared()); 38 assert(!m.try_lock_shared()); 39 while(!m.try_lock_shared()) 40 ; 41 time_point t1 = Clock::now(); 42 m.unlock_shared(); 43 ns d = t1 - t0 - ms(250); 44 assert(d < ms(200)); // within 200ms 45 } 46 47 48 int main() 49 { 50 m.lock(); 51 std::vector<std::thread> v; 52 for (int i = 0; i < 5; ++i) 53 v.push_back(std::thread(f)); 54 std::this_thread::sleep_for(ms(250)); 55 m.unlock(); 56 for (auto& t : v) 57 t.join(); 58 } 59
