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 12 13 // FLAKY_TEST. 14 15 // <shared_mutex> 16 17 // class shared_timed_mutex; 18 19 // void lock_shared(); 20 21 #include <shared_mutex> 22 #include <thread> 23 #include <vector> 24 #include <cstdlib> 25 #include <cassert> 26 27 #include "test_macros.h" 28 29 std::shared_timed_mutex m; 30 31 typedef std::chrono::system_clock Clock; 32 typedef Clock::time_point time_point; 33 typedef Clock::duration duration; 34 typedef std::chrono::milliseconds ms; 35 typedef std::chrono::nanoseconds ns; 36 37 38 ms WaitTime = ms(250); 39 40 // Thread sanitizer causes more overhead and will sometimes cause this test 41 // to fail. To prevent this we give Thread sanitizer more time to complete the 42 // test. 43 #if !defined(TEST_HAS_SANITIZERS) 44 ms Tolerance = ms(50); 45 #else 46 ms Tolerance = ms(50 * 5); 47 #endif 48 49 50 void f() 51 { 52 time_point t0 = Clock::now(); 53 m.lock_shared(); 54 time_point t1 = Clock::now(); 55 m.unlock_shared(); 56 ns d = t1 - t0 - WaitTime; 57 assert(d < Tolerance); // within tolerance 58 } 59 60 void g() 61 { 62 time_point t0 = Clock::now(); 63 m.lock_shared(); 64 time_point t1 = Clock::now(); 65 m.unlock_shared(); 66 ns d = t1 - t0; 67 assert(d < Tolerance); // within tolerance 68 } 69 70 71 int main() 72 { 73 m.lock(); 74 std::vector<std::thread> v; 75 for (int i = 0; i < 5; ++i) 76 v.push_back(std::thread(f)); 77 std::this_thread::sleep_for(WaitTime); 78 m.unlock(); 79 for (auto& t : v) 80 t.join(); 81 m.lock_shared(); 82 for (auto& t : v) 83 t = std::thread(g); 84 std::thread q(f); 85 std::this_thread::sleep_for(WaitTime); 86 m.unlock_shared(); 87 for (auto& t : v) 88 t.join(); 89 q.join(); 90 } 91
