IStorage::CreateStream

Creates and opens a stream object with the specified name contained in this storage object. All elements within a storage object

including both streams and other storage objects

are kept in the same name space.

HRESULT CreateStream(

const wchar_t * 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 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]Points to the location where the new IStream interface pointer is returned; only valid if the operation is successful. This parameter is set to NULL if an error occurs.

Return Values
S_OK

The new stream was successfully created

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 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.

Comments
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. The destruction of the old stream and the creation of the new stream object are both 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.

Note to Callers
The OLE-provided compound file implementation of the IStorage::CreateStream method does not support the following behaviors:

The STGM_DELETEONRELEASE flag is not supported.
Transacted mode is not supported for stream objects.
Opening the same stream more than once from the same storage is not supported. The STGM_SHARE_EXCLUSIVE flag must be specified.

Other implementations of IStorage might support these features.