IStorage::OpenStream method (objidl.h)

Article
10/13/2021

The OpenStream method opens an existing stream object within this storage object in the specified access mode.

Syntax

HRESULT OpenStream(
  [in]  const OLECHAR *pwcsName,
  [in]  void          *reserved1,
  [in]  DWORD         grfMode,
  [in]  DWORD         reserved2,
  [out] IStream       **ppstm
);

Parameters

[in] pwcsName

A pointer to a wide character null-terminated Unicode string that contains the name of the stream to open. The 000 through 01f characters, serving as the first character of the stream/storage name, are reserved for use by OLE. This is a compound file restriction, not a structured storage restriction.

[in] reserved1

Reserved for future use; must be NULL.

[in] grfMode

Specifies the access mode to be assigned to the open stream. For more information and descriptions of possible values, see STGM Constants. Other modes you choose must at least specify STGM_SHARE_EXCLUSIVE when calling this method in the compound file implementation.

[in] reserved2

Reserved for future use; must be zero.

[out] ppstm

A pointer to 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 value

This method can return one of these values.

Return code	Description
S_OK	The stream was successfully opened.
E_PENDING	Asynchronous Storage only: Part or all of the stream data is currently unavailable.
STG_E_ACCESSDENIED	Not enough 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 parameter is not a valid STGM constants value.
STG_E_INVALIDFUNCTION	The specified combination of flags in the grfMode parameter is not supported; for example, when 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 not valid.
STG_E_INVALIDPARAMETER	One of the parameters was not valid.
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.

Remarks

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 need to be stricter than those on their parent storages. Compound-file streams must be opened with STGM_SHARE_EXCLUSIVE.

Requirements

Requirement	Value
Minimum supported client	Windows 2000 Professional [desktop apps \| UWP apps]
Minimum supported server	Windows 2000 Server [desktop apps \| UWP apps]
Target Platform	Windows
Header	objidl.h
Library	Uuid.lib
DLL	Ole32.dll