mutex_try_to_lock.pass.cpp (1794B)
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++98, c++03, c++11 12 13 // FLAKY_TEST 14 15 // <shared_mutex> 16 17 // template <class Mutex> class shared_lock; 18 19 // shared_lock(mutex_type& m, try_to_lock_t); 20 21 #include <shared_mutex> 22 #include <thread> 23 #include <vector> 24 #include <cstdlib> 25 #include <cassert> 26 27 std::shared_timed_mutex m; 28 29 typedef std::chrono::system_clock Clock; 30 typedef Clock::time_point time_point; 31 typedef Clock::duration duration; 32 typedef std::chrono::milliseconds ms; 33 typedef std::chrono::nanoseconds ns; 34 35 void f() 36 { 37 time_point t0 = Clock::now(); 38 { 39 std::shared_lock<std::shared_timed_mutex> lk(m, std::try_to_lock); 40 assert(lk.owns_lock() == false); 41 } 42 { 43 std::shared_lock<std::shared_timed_mutex> lk(m, std::try_to_lock); 44 assert(lk.owns_lock() == false); 45 } 46 { 47 std::shared_lock<std::shared_timed_mutex> lk(m, std::try_to_lock); 48 assert(lk.owns_lock() == false); 49 } 50 while (true) 51 { 52 std::shared_lock<std::shared_timed_mutex> lk(m, std::try_to_lock); 53 if (lk.owns_lock()) 54 break; 55 } 56 time_point t1 = Clock::now(); 57 ns d = t1 - t0 - ms(250); 58 assert(d < ms(200)); // within 200ms 59 } 60 61 int main() 62 { 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 }