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 // <condition_variable> 11 12 // class condition_variable; 13 14 // template <class Rep, class Period, class Predicate> 15 // bool 16 // wait_for(unique_lock<mutex>& lock, 17 // const chrono::duration<Rep, Period>& rel_time, 18 // Predicate pred); 19 20 #include <condition_variable> 21 #include <mutex> 22 #include <thread> 23 #include <chrono> 24 #include <cassert> 25 26 class Pred 27 { 28 int& i_; 29 public: Pred(int & i)30 explicit Pred(int& i) : i_(i) {} 31 operator ()()32 bool operator()() {return i_ != 0;} 33 }; 34 35 std::condition_variable cv; 36 std::mutex mut; 37 38 int test1 = 0; 39 int test2 = 0; 40 41 int runs = 0; 42 f()43void f() 44 { 45 typedef std::chrono::system_clock Clock; 46 typedef std::chrono::milliseconds milliseconds; 47 std::unique_lock<std::mutex> lk(mut); 48 assert(test2 == 0); 49 test1 = 1; 50 cv.notify_one(); 51 Clock::time_point t0 = Clock::now(); 52 bool r = cv.wait_for(lk, milliseconds(250), Pred(test2)); 53 Clock::time_point t1 = Clock::now(); 54 if (runs == 0) 55 { 56 assert(t1 - t0 < milliseconds(250)); 57 assert(test2 != 0); 58 } 59 else 60 { 61 assert(t1 - t0 - milliseconds(250) < milliseconds(50)); 62 assert(test2 == 0); 63 } 64 ++runs; 65 } 66 main()67int main() 68 { 69 { 70 std::unique_lock<std::mutex>lk(mut); 71 std::thread t(f); 72 assert(test1 == 0); 73 while (test1 == 0) 74 cv.wait(lk); 75 assert(test1 != 0); 76 test2 = 1; 77 lk.unlock(); 78 cv.notify_one(); 79 t.join(); 80 } 81 test1 = 0; 82 test2 = 0; 83 { 84 std::unique_lock<std::mutex>lk(mut); 85 std::thread t(f); 86 assert(test1 == 0); 87 while (test1 == 0) 88 cv.wait(lk); 89 assert(test1 != 0); 90 lk.unlock(); 91 t.join(); 92 } 93 } 94