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      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 // <mutex>
     11 
     12 // template <class Mutex> class unique_lock;
     13 
     14 // template <class Rep, class Period>
     15 //   bool try_lock_for(const chrono::duration<Rep, Period>& rel_time);
     16 
     17 #include <mutex>
     18 #include <cassert>
     19 
     20 bool try_lock_for_called = false;
     21 
     22 typedef std::chrono::milliseconds ms;
     23 
     24 struct mutex
     25 {
     26     template <class Rep, class Period>
     27         bool try_lock_for(const std::chrono::duration<Rep, Period>& rel_time)
     28     {
     29         assert(rel_time == ms(5));
     30         try_lock_for_called = !try_lock_for_called;
     31         return try_lock_for_called;
     32     }
     33     void unlock() {}
     34 };
     35 
     36 mutex m;
     37 
     38 int main()
     39 {
     40     std::unique_lock<mutex> lk(m, std::defer_lock);
     41     assert(lk.try_lock_for(ms(5)) == true);
     42     assert(try_lock_for_called == true);
     43     assert(lk.owns_lock() == true);
     44     try
     45     {
     46         lk.try_lock_for(ms(5));
     47         assert(false);
     48     }
     49     catch (std::system_error& e)
     50     {
     51         assert(e.code().value() == EDEADLK);
     52     }
     53     lk.unlock();
     54     assert(lk.try_lock_for(ms(5)) == false);
     55     assert(try_lock_for_called == false);
     56     assert(lk.owns_lock() == false);
     57     lk.release();
     58     try
     59     {
     60         lk.try_lock_for(ms(5));
     61         assert(false);
     62     }
     63     catch (std::system_error& e)
     64     {
     65         assert(e.code().value() == EPERM);
     66     }
     67 }
     68