简单单例模式

#include <cassert>

template <typename T> class Singleton

{

    static T* ms_Singleton;

public:

    Singleton( void )

    {

        assert( !ms_Singleton );

        int offset = (int)(T*)1 - (int)(Singleton <T>*)(T*)1;

        ms_Singleton = (T*)((int)this + offset);

    }

   ~Singleton( void )

        {  assert( ms_Singleton );  ms_Singleton = 0;  }

    static T& GetSingleton( void )

        {  assert( ms_Singleton );  return ( *ms_Singleton );  }

    static T* GetSingletonPtr( void )

        {  return ( ms_Singleton );  }

};

template <typename T> T* Singleton <T>::ms_Singleton = 0; 

template <typename T> T* Singleton <T>::ms_Singleton = 0;