condition_variable

#include <iostream> #include <thread> #include <mutex> #include <condition_variable> int count; std::mutex count_mutex; std::condition_variable_any count_cv; void thread_start() { count_mutex.lock(); count_cv.wait(count_mutex, []{return count >= 10000;}); int val = count; count_mutex.unlock(); std::cout << "val = " << val << std::endl; } int main() { std::thread t1(thread_start); for (int i = 0; i < 100000; ++i) { // These three lines: count_mutex.lock(); count = i; count_mutex.unlock(); // count was changed, so wake up t1 and have it check the condition again. count_cv.notify_one(); } t1.join(); }