This method opens an existing stream object within this storage object according to the specified access mode.

HRESULT OpenStream( 
const WCHAR *pwcsName, 
void *reserved1, 
DWORD grfMode, 
DWORD reserved2, 
IStream **ppstm 


  • pwcsName
    [in] Pointer to a wide character string that contains the name of the stream to open.
  • reserved1
    [in] Reserved for future use; set to NULL.
  • grfMode
    [in] Specifies the access mode to be assigned to the open stream. See the STGM enumeration values for descriptions of the possible values. Whatever other modes you may choose, you must at least specify STGM_SHARE_EXCLUSIVE when calling this method.
  • reserved2
    [in] Reserved for future use; set to zero.
  • ppstm
    [out] Address of IStream* pointer variable that receives the interface pointer to the newly-opened stream object. If an error occurs, *ppstm must be set to NULL.

Return Values

One of the values described in the following table is returned.

Value Description
S_OK The stream was successfully opened.
E_PENDING Asynchronous Storage only: Part or all of the streams data is currently unavailable. For more information see IFillLockBytes and Asynchronous Storage.
STG_E_ACCESSDENIED Insufficient permissions to open stream.
STG_E_FILENOTFOUND The stream with specified name does not exist.
STG_E_INSUFFICIENTMEMORY The stream was not opened 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 opened because there are too many open files.


IStorage::OpenStream opens an existing stream object within this storage object in the access mode specified in grfMode. There are restrictions on the permissions that can be given in grfMode. For example, the permissions on this storage object restrict the permissions on its streams. In general, access restrictions on streams should be stricter than those on their parent storages. Compound-file streams must be opened with STGM_SHARE_EXCLUSIVE.


Runs on Versions Defined in Include Link to
Windows CE OS 2.0 and later Objidl.h    

Note   This API is part of the complete Windows CE OS package as provided by Microsoft. The functionality of a particular platform is determined by the original equipment manufacturer (OEM) and some devices may not support this API.

 Last updated on Tuesday, July 13, 2004

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