# IStorage::CreateStream

Creates and opens a stream object with the specified name contained in this storage object. All elements within a storage object &emdash; both streams and other storage objects &emdash; are kept in the same name space.

HRESULT CreateStream(

const WCHAR * pwcsName, | //Points to the name of the new stream
DWORD grfMode, | //Access mode for the new stream
DWORD reserved1, | //Reserved; must be zero
DWORD reserved2, | //Reserved; must be zero
IStream ** ppstm | //Points to new stream object
); |

Parameters

pwcsName
  [in] Points to a wide character string that contains the name of the newly created stream. This name can be used later to open or reopen the stream.
grfMode
  [in] Specifies the access mode to use when opening the newly created stream. See the STGM enumeration values for descriptions of the possible values.
reserved1
  [in] Reserved for future use; must be zero.
reserved2
  [in] Reserved for future use; must be zero.
ppstm
  [out] On return, points to the location of the new IStream interface pointer. This is only valid if the operation is successful. When an error occurs, this parameter is set to NULL.

Return Values

S_OK
  The new stream was successfully created
E_PENDING
  Asynchronous Storage only: Part or all of the necessary data is currently unavailable. For more information see IFillLockBytes and Asynchronous Storage.
STG_E_ACCESSDENIED
  Insufficient permissions to create stream.
STG_E_FILEALREADYEXISTS
  The name specified for the stream already exists in the storage object and the grfmode flag includes the flag STGM_FAILIFTHERE.
STG_E_INSUFFICIENTMEMORY
  The stream was not created due to a lack of memory.
STG_E_INVALIDFLAG
  The value specified for the grfMode flag is not a valid STGM enumeration value.
STG_E_INVALIDFUNCTION
  The specified combination of grfMode flags is not supported. For example, if this method is called without the STGM_SHARE_EXCLUSIVE flag.
STG_E_INVALIDNAME
  Invalid value for pwcsName.
STG_E_INVALIDPOINTER
  The pointer specified for the stream object was invalid.
STG_E_INVALIDPARAMETER
  One of the parameters was invalid.
STG_E_REVERTED
  The storage object has been invalidated by a revert operation above it in the transaction tree.
STG_E_TOOMANYOPENFILES
  The stream was not created because there are too many open files.

Remarks

If a stream with the name specified in the pwcsName parameter already exists and the grfMode parameter includes the STGM_CREATE flag, the existing stream is replaced by a newly created one. Both the destruction of the old stream and the creation of the new stream object are subject to the transaction mode on the parent storage object.

If the stream already exists and grfMode is set to STGM_FAILIFTHERE, this method fails with the return value STG_E_FILEALREADYEXISTS.

See Also

IStorage - Compound File Implementation, IStorage::OpenStream, IStream