libcxx/test/std/thread/thread.condition/thread.condition.condvar/wait_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 Predicate>
  17 //   void wait(unique_lock<mutex>& lock, Predicate pred);
  18
  19 #include <condition_variable>
  20 #include <mutex>
  21 #include <thread>
  22 #include <functional>
  23 #include <cassert>
  24
  25 #include "make_test_thread.h"
  26 #include "test_macros.h"
  27
  28 std::condition_variable cv;
  29 std::mutex mut;
  30
  31 int test1 = 0;
  32 int test2 = 0;
  33
  34 class Pred
  35 {
  36     int& i_;
  37 public:
  38     explicit Pred(int& i) : i_(i) {}
  39
  40     bool operator()() {return i_ != 0;}
  41 };
  42
  43 void f()
  44 {
  45     std::unique_lock<std::mutex> lk(mut);
  46     assert(test2 == 0);
  47     test1 = 1;
  48     cv.notify_one();
  49     cv.wait(lk, Pred(test2));
  50     assert(test2 != 0);
  51 }
  52
  53 int main(int, char**)
  54 {
  55     std::unique_lock<std::mutex>lk(mut);
  56     std::thread t = support::make_test_thread(f);
  57     assert(test1 == 0);
  58     while (test1 == 0)
  59         cv.wait(lk);
  60     assert(test1 != 0);
  61     test2 = 1;
  62     lk.unlock();
  63     cv.notify_one();
  64     t.join();
  65
  66   return 0;
  67 }