constexpr int _intMaxThreads = 10; //thread::hardware_concurrency(); //max threads in a pool #include #include #include #include #include #include #include #include using namespace std; class ThreadPool { public: ThreadPool(); ~ThreadPool(); void addTask(function ptaskFunction); private: ThreadPool(const ThreadPool& obj) = delete;//no copy constructor ThreadPool& operator= (const ThreadPool& obj) = delete;//no asignment constructor array m_arrThreads;//threads which will work as independent entity void fetchTaskFromQueue();//thread to be running continuosly from queue mutex m_mutexQueue; condition_variable m_CVQueue; queue> m_queueTasks;//this is list of functions to be done from threads of thread pool..Task function can be of type only void Fun() }; ThreadPool::ThreadPool() { for (int iCurThreadNo = 0; iCurThreadNo < _intMaxThreads; ++iCurThreadNo) { m_arrThreads[iCurThreadNo] = thread(&ThreadPool::fetchTaskFromQueue, this); //m_arrThreads[iCurThreadNo].detach(); } } ThreadPool::~ThreadPool() { for (int iCurThreadNo = 0; iCurThreadNo < _intMaxThreads; ++iCurThreadNo) { m_arrThreads[iCurThreadNo].join(); } } void ThreadPool::fetchTaskFromQueue() { while (true) { function task; { unique_lock locker(m_mutexQueue);//Lock the queue m_CVQueue.wait(locker, [&]() {return !m_queueTasks.empty(); });//wait till queue is not empty //fetch first task from top of the queue task = m_queueTasks.front(); //remove entry m_queueTasks.pop(); } //now,critical section is done of assigning task to queue. Now, we have task to be done. task(); } } void ThreadPool::addTask(function ptaskFunction) { { unique_lock locker(m_mutexQueue);//Lock the queue //add task to be performed to queue m_queueTasks.push(ptaskFunction); } //notify to one thread that queue is not empty now so perform task m_CVQueue.notify_one(); } mutex output; set setOutput; void Prepareasks() { unique_lock lock(output); setOutput.insert("Hi"); } void printAll() { for (const auto& elem : setOutput) { cout << elem << endl; } } void print() { cout << "Hi" << endl; } int main() { { ThreadPool obj; for (int i = 1; i <= 100; ++i) { //obj.addTask(print); obj.addTask(Prepareasks); } } printAll(); return 0; }

Implement_ThreadPool