COM provides two built-in ISTREAM objects, one is in the global heap, one is using files
Full bureau:
use
CreateStreamonhglobal
File use
STGCREATEDOCFILE gets the iStorage interface pointer, use iStorage's method CreateStream or OpenStream Gets the IStream interface pointer
See MSDN for details
Http://msdn.microsoft.com/library/default.asp?url=/library/en-us/stg/stg/istream_compound_file_implementation.asp
