IStream::Clone

Creates a new stream object with its own seek pointer that references the same bytes as the original stream.

HRESULT Clone(

IStream ** ppstm	//Points to location for pointer to the new stream object
);

Parameter
ppstm

[out]Points to location for the pointer to the new stream object. If an error occurs, this parameter is NULL.

Return Values
S_OK

The stream was successfully cloned.

STG_E_INSUFFICIENT_MEMORY

The stream was not cloned due to a lack of memory.

STG_E_INVALIDPOINTER

The ppStm pointer is not valid.

Comments
This method creates a new stream object for accessing the same bytes but using a separate seek pointer. The new stream object sees the same data as the source stream object. Changes written to one object are immediately visible in the other. Range locking is shared between the stream objects.

The initial setting of the seek pointer in the cloned stream instance is the same as the current setting of the seek pointer in the original stream at the time of the clone operation.