IStorage::OpenStream

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11/18/2015

A version of this page is also available for

4/8/2010

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

Syntax

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

Parameters

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] 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 Value

The following table shows the return values for this method.

Value	Description
S_OK	The stream was successfully opened.
E_PENDING	Asynchronous Storage only: Part or all of the stream's data is currently unavailable. For more information see the IFillLockBytes interface 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.

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 should be stricter than those on their parent storages.

Compound-file streams must be opened with STGM_SHARE_EXCLUSIVE.

To determine whether the platform supports this interface, see Determining Supported COM APIs.

Requirements

Header	objidl.h, objidl.idl
Library	ole32.lib, uuid.lib
Windows Embedded CE	Windows CE 2.0 and later
Windows Mobile	Windows Mobile Version 5.0 and later

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