#include using namespace std; #include #include mutex g_mutex; class Singleton { private: Singleton() {}; public: static Singleton* pSingleton; /*static Singleton* GetObjPointer() { g_mutex.lock(); if(pSingleton==nullptr) { cout << endl << "Object constructed...." << endl; pSingleton = new Singleton(); g_mutex.unlock(); return pSingleton; } else { cout << endl << "Object re-used...." << endl; g_mutex.unlock(); return pSingleton; } }*/ //better method than above as there is a chance of dead lock in above code static Singleton* GetObjPointer() { std::lock_guard lock(g_mutex); if(pSingleton==nullptr) { cout << endl << "Object constructed...." << endl; pSingleton = new Singleton(); return pSingleton; } else { cout << endl << "Object re-used...." << endl; return pSingleton; } } void display(std::thread::id iid) { cout << "From thread id " << iid << " ; Hello count 1...." << endl; } }; Singleton* Singleton::pSingleton = nullptr; void f(std::thread::id iid) { Singleton* pobj = Singleton::GetObjPointer(); pobj->display(iid); cout << endl; } int main() { thread t1(f,this_thread::get_id()); thread t2(f,this_thread::get_id()); thread t3(f,this_thread::get_id()); thread t4(f,this_thread::get_id()); thread t5(f,this_thread::get_id()); t1.join(); t2.join(); t3.join(); t4.join(); t5.join(); return 0; }

Singleton_MultiThread