libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/mutex.pass.cpp

   1 //===----------------------------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // UNSUPPORTED: no-threads
  10 // UNSUPPORTED: c++03, c++11
  11 // ALLOW_RETRIES: 2
  12
  13 // <shared_mutex>
  14
  15 // template <class Mutex> class shared_lock;
  16
  17 // explicit shared_lock(mutex_type& m);
  18
  19 // template<class _Mutex> shared_lock(shared_lock<_Mutex>)
  20 //     -> shared_lock<_Mutex>;  // C++17
  21
  22 #include <cassert>
  23 #include <chrono>
  24 #include <cstdlib>
  25 #include <shared_mutex>
  26 #include <thread>
  27 #include <vector>
  28
  29 #include "make_test_thread.h"
  30 #include "test_macros.h"
  31
  32 typedef std::chrono::system_clock Clock;
  33 typedef Clock::time_point time_point;
  34 typedef Clock::duration duration;
  35 typedef std::chrono::milliseconds ms;
  36 typedef std::chrono::nanoseconds ns;
  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_IS_EXECUTED_IN_A_SLOW_ENVIRONMENT)
  44 ms Tolerance = ms(50);
  45 #else
  46 ms Tolerance = ms(50 * 5);
  47 #endif
  48
  49 std::shared_timed_mutex m;
  50
  51 void f()
  52 {
  53     time_point t0 = Clock::now();
  54     time_point t1;
  55     {
  56     std::shared_lock<std::shared_timed_mutex> ul(m);
  57     t1 = Clock::now();
  58     }
  59     ns d = t1 - t0 - WaitTime;
  60     assert(d < Tolerance);  // within tolerance
  61 }
  62
  63 void g()
  64 {
  65     time_point t0 = Clock::now();
  66     time_point t1;
  67     {
  68     std::shared_lock<std::shared_timed_mutex> ul(m);
  69     t1 = Clock::now();
  70     }
  71     ns d = t1 - t0;
  72     assert(d < Tolerance);  // within tolerance
  73 }
  74
  75 int main(int, char**)
  76 {
  77     std::vector<std::thread> v;
  78     {
  79         m.lock();
  80         for (int i = 0; i < 5; ++i)
  81             v.push_back(support::make_test_thread(f));
  82         std::this_thread::sleep_for(WaitTime);
  83         m.unlock();
  84         for (auto& t : v)
  85             t.join();
  86     }
  87     {
  88         m.lock_shared();
  89         for (auto& t : v)
  90             t = support::make_test_thread(g);
  91         std::thread q = support::make_test_thread(f);
  92         std::this_thread::sleep_for(WaitTime);
  93         m.unlock_shared();
  94         for (auto& t : v)
  95             t.join();
  96         q.join();
  97     }
  98
  99 #if TEST_STD_VER >= 17
 100     std::shared_lock sl(m);
 101     static_assert((std::is_same<decltype(sl), std::shared_lock<decltype(m)>>::value), "" );
 102 #endif
 103
 104   return 0;
 105 }