libcxx/test/std/thread/thread.condition/thread.condition.condvar/wait_for_pred.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 // ALLOW_RETRIES: 2
  11
  12 // <condition_variable>
  13
  14 // class condition_variable;
  15
  16 // template <class Rep, class Period, class Predicate>
  17 //     bool
  18 //     wait_for(unique_lock<mutex>& lock,
  19 //              const chrono::duration<Rep, Period>& rel_time,
  20 //              Predicate pred);
  21
  22 #include <condition_variable>
  23 #include <mutex>
  24 #include <thread>
  25 #include <chrono>
  26 #include <cassert>
  27
  28 #include "make_test_thread.h"
  29 #include "test_macros.h"
  30
  31 class Pred
  32 {
  33     int& i_;
  34 public:
  35     explicit Pred(int& i) : i_(i) {}
  36
  37     bool operator()() {return i_ != 0;}
  38 };
  39
  40 std::condition_variable cv;
  41 std::mutex mut;
  42
  43 int test1 = 0;
  44 int test2 = 0;
  45
  46 int runs = 0;
  47
  48 void f()
  49 {
  50     typedef std::chrono::system_clock Clock;
  51     typedef std::chrono::milliseconds milliseconds;
  52     std::unique_lock<std::mutex> lk(mut);
  53     assert(test2 == 0);
  54     test1 = 1;
  55     cv.notify_one();
  56     Clock::time_point t0 = Clock::now();
  57     bool r = cv.wait_for(lk, milliseconds(250), Pred(test2));
  58     ((void)r); // Prevent unused warning
  59     Clock::time_point t1 = Clock::now();
  60     if (runs == 0)
  61     {
  62         assert(t1 - t0 < milliseconds(250));
  63         assert(test2 != 0);
  64     }
  65     else
  66     {
  67         assert(t1 - t0 - milliseconds(250) < milliseconds(50));
  68         assert(test2 == 0);
  69     }
  70     ++runs;
  71 }
  72
  73 int main(int, char**)
  74 {
  75     {
  76         std::unique_lock<std::mutex>lk(mut);
  77         std::thread t = support::make_test_thread(f);
  78         assert(test1 == 0);
  79         while (test1 == 0)
  80             cv.wait(lk);
  81         assert(test1 != 0);
  82         test2 = 1;
  83         lk.unlock();
  84         cv.notify_one();
  85         t.join();
  86     }
  87     test1 = 0;
  88     test2 = 0;
  89     {
  90         std::unique_lock<std::mutex>lk(mut);
  91         std::thread t = support::make_test_thread(f);
  92         assert(test1 == 0);
  93         while (test1 == 0)
  94             cv.wait(lk);
  95         assert(test1 != 0);
  96         lk.unlock();
  97         t.join();
  98     }
  99
 100   return 0;
 101 }