# IStorage::OpenStorage

Opens an existing storage object with the specified name in the specified access mode.

HRESULT OpenStorage(

const WCHAR * pwcsName, | //Points to the name of the storage object to open
IStorage * pstgPriority, | //Points to previous opening of the storage object
DWORD grfMode, | //Access mode for the new storage object
SNB snbExclude, | //Points to a block of stream names in the storage object
DWORD reserved, | //Reserved; must be zero
IStorage ** ppstg | //Points to opened storage object
); |

Parameters

pwcsName
  [in] Points to a wide character string that contains the name of the storage object to open. It is ignored if pstgPriority is non-NULL.
pstgPriority
  [in] If the pstgPriority parameter is not NULL, it is an IStorage pointer to a previous opening of an element of the storage object, usually one that was opened in priority mode. The storage object should be closed and re-opened according to grfMode. When the IStorage::OpenStorage method returns, pstgPriority is no longer valid. Use the value supplied in the ppstg parameter. If the pstgPriority parameter is NULL, it is ignored.
grfMode
  [in] Specifies the access mode to use when opening the storage object. 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.
snbExclude
  [in] Must be NULL. A non-NULL value will return STG_E_INVALIDPARAMETER.
reserved
  [in] Reserved for future use; must be zero.
ppstg
  [out] When the operation is successful, points to the location of an IStorage pointer to the opened storage object. This parameter is set to NULL if an error occurs.

Return Values

S_OK
  The storage object was opened successfully.
E_PENDING
  Asynchronous Storage only: Part or all of the storage’s data is currently unavailable. For more information see IFillLockBytes and Asynchronous Storage.
STG_E_ACCESSDENIED
  Insufficient permissions to open storage object.
STG_E_FILENOTFOUND
  The storage object with the specified name does not exist.
STG_E_INSUFFICIENTMEMORY
  The storage object 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.
STG_E_INVALIDNAME
  Invalid value for pwcsName.
STG_E_INVALIDPOINTER
  The pointer specified for the storage 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 storage object was not created because there are too many open files.
STG_S_CONVERTED
  The existing stream with the specified name was replaced with a new storage object containing a single stream called CONTENTS. In direct mode, the new storage is immediately written to disk. In transacted mode, the new storage is written to a temporary storage in memory and later written to disk when it is committed.

Remarks

Storage objects can be opened with STGM_DELETEONRELEASE, in which case the object is destroyed when it receives its final release. This is useful for creating temporary storage objects.

See Also

IStorage - Compound File Implementation, IStorage::CreateStorage