template<typename _OtherIID>   
_com_ptr_t& operator=( const _com_ptr_t<_OtherIID>& p );  
  
// Sets a smart pointer to be a different smart pointer of a different   
// type or a different raw interface pointer. QueryInterface is called   
// to find an interface pointer of this smart pointer's type, and   
// Release is called to decrement the reference count for the previously   
// encapsulated pointer. If QueryInterface fails with an E_NOINTERFACE,   
// a NULL smart pointer results.  
template<typename _InterfaceType>   
_com_ptr_t& operator=(_InterfaceType* p );  
  
// Encapsulates a raw interface pointer of this smart pointer's type.   
// AddRef is called to increment the reference count for the encapsulated  
// interface pointer, and Release is called to decrement the reference   
// count for the previously encapsulated pointer.  
template<> _com_ptr_t&    
operator=( Interface* pInterface ) throw();  
  
// Sets a smart pointer to be a copy of another instance of the same   
// smart pointer of the same type. AddRef is called to increment the   
// reference count for the encapsulated interface pointer, and Release   
// is called to decrement the reference count for the previously   
// encapsulated pointer.  
_com_ptr_t& operator=( const _com_ptr_t& cp ) throw();  
  
// Sets a smart pointer to NULL. The NULL argument must be a zero.  
_com_ptr_t& operator=( int null );  

// Sets a smart pointer to be a _variant_t object. The encapsulated   
// VARIANT must be of type VT_DISPATCH or VT_UNKNOWN, or it can be   
// converted to one of these two types. If QueryInterface fails with an   
// E_NOINTERFACE error, a NULL smart pointer results.  
_com_ptr_t& operator=( const _variant_t& varSrc );