C++11 Multithreading - Producer Consumer (Condition Variable)

The Bounded-Buffer problem, also known as the producer-consumer problem, can be easily solved using the semaphore. In C++, there are no semaphores, but we can use the condition variable instead.

#include <thread>
#include <mutex>
#include <condition_variable>
using namespace std;

class BoundedBuffer{
private:
    deque<int> buffer;
    int size=10;
    mutex m;
    condition_variable cv;
public:
    BoundedBuffer(){};
    void produce(int num){
        unique_lock<mutex> lock(m);
        cv.wait(lock,[this](){return buffer.size()<size;});
        buffer.push_back(num);
        cout << "produce " << num << '\n';
        cv.notify_all();
    }
    int consume(){
        unique_lock<mutex> lock(m);
        cv.wait(lock,[this](){return buffer.size()>0;});
        int res=buffer.front(); buffer.pop_front();
        cout << "consume " << res << '\n';
        cv.notify_all();
        return res;
    }
};

int main(){
    BoundedBuffer bf;
    auto producer=[&](){
        for (int i=0;i<5;++i) bf.produce(i);
    };
    auto consumer=[&](){
        for (int i=0;i<5;++i) bf.consume();
    };
    thread producer_thread(producer);
    thread consumer_thread(consumer);
    producer_thread.join();
    consumer_thread.join();
    return 0;
}

Reference

https://codereview.stackexchange.com/questions/84109/a-multi-threaded-producer-consumer-with-c11