Singleton Design Pattern with example C++ code

The Singleton design pattern ensures only one instance of a class in an application. For example, Interfaces object need by both GUI and Back-end class. But only one interface object enough for the whole application (GUI + interface + Back-end)

Here need to develop the interface class as a Singleton class.

static CInterface *s_ptrInterface = 0;

class CInterface

{

private:

CInterface();

~ CInterface();

public:

static CInterface* getInterface()

{

 lock(); // for thread safe.

if( 0 != s_ptrInterface )

s_ptrInterface = new CInterface();

unlock();

return s_ptrInterface ;

}

}

Need to create the object for CInterface like below,

CInterface:: getInterface() // it’s always return the same object