Multithreading

multithread.cpp

#include <assert.h>
#include <thread>
#include <mutex>
#include <future>
#include <iostream>
#include <deque>

int a = 0;
std::mutex mutex;

void increment()
{
	while (true)
	{
		mutex.lock();
		int prev = a;
		a++;
		assert((prev + 1) == a);
		mutex.unlock();
	}
}

int main2()
{
	std::thread t1(increment);
	std::thread t2(increment);

	t1.join();
	t2.join();

	return 0;
}

int value = 0;
bool value_ready = false;

void LongOperation()
{

	std::cout << "long operation started" << std::endl;
	{
		std::unique_lock<std::mutex> lock_A(mutex);
		//	std::this_thread::sleep_for(std::chrono::seconds(1));
		//	value = 42;
		//	value_ready = true;
		std::cout << "long operation done" << std::endl;
	}
}

std::condition_variable cv;
std::deque<int> queue;

void Producer()
{
	for (int i = 0; i < 10; i++)
	{
		std::this_thread::sleep_for(std::chrono::seconds(1));
		{
			std::unique_lock<std::mutex> lock(mutex);
			queue.push_back(i);
			std::cout << "pushed: " << i << std::endl;
		}
		cv.notify_all();
		std::this_thread::sleep_for(std::chrono::microseconds(10));
		cv.notify_all();
	}
}

void Consumer()
{
	while (true)
	{
		int value = -1;
		{
			std::unique_lock<std::mutex> lock(mutex);
			cv.wait(lock, []() { std::cout << "attempt" <<std::endl; return !queue.empty(); });

			value = queue.front();
			queue.pop_front();
		}
		std::cout << "received: " << value << std::endl;
	}
}

int main()
{
	std::thread t1(Producer);
	std::thread t2(Consumer);

	t1.join();
	t2.join();

	return 0;
}