src/third_party/libc++/trunk/test/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/mutex_try_to_lock.pass.cpp

   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 // <shared_mutex>
  11
  12 // template <class Mutex> class shared_lock;
  13
  14 // shared_lock(mutex_type& m, try_to_lock_t);
  15
  16 #include <shared_mutex>
  17 #include <thread>
  18 #include <vector>
  19 #include <cstdlib>
  20 #include <cassert>
  21
  22 #if _LIBCPP_STD_VER > 11
  23
  24 std::shared_timed_mutex m;
  25
  26 typedef std::chrono::system_clock Clock;
  27 typedef Clock::time_point time_point;
  28 typedef Clock::duration duration;
  29 typedef std::chrono::milliseconds ms;
  30 typedef std::chrono::nanoseconds ns;
  31
  32 void f()
  33 {
  34     time_point t0 = Clock::now();
  35     {
  36         std::shared_lock<std::shared_timed_mutex> lk(m, std::try_to_lock);
  37         assert(lk.owns_lock() == false);
  38     }
  39     {
  40         std::shared_lock<std::shared_timed_mutex> lk(m, std::try_to_lock);
  41         assert(lk.owns_lock() == false);
  42     }
  43     {
  44         std::shared_lock<std::shared_timed_mutex> lk(m, std::try_to_lock);
  45         assert(lk.owns_lock() == false);
  46     }
  47     while (true)
  48     {
  49         std::shared_lock<std::shared_timed_mutex> lk(m, std::try_to_lock);
  50         if (lk.owns_lock())
  51             break;
  52     }
  53     time_point t1 = Clock::now();
  54     ns d = t1 - t0 - ms(250);
  55     assert(d < ms(200));  // within 200ms
  56 }
  57
  58 #endif  // _LIBCPP_STD_VER > 11
  59
  60 int main()
  61 {
  62 #if _LIBCPP_STD_VER > 11
  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 #endif  // _LIBCPP_STD_VER > 11
  72 }