IStorage::OpenStream
Opens an
existing stream object within this storage object in the specified access mode.
HRESULT OpenStream(
|
const WCHAR * pwcsName, |
//Points
to name of stream to open |
|
void * reserved1, |
//Reserved;
must be NULL |
|
DWORD grfMode, |
//Access
mode for the new stream |
|
DWORD reserved2, |
//Reserved;
must be zero |
|
IStream ** ppstm |
//Indirect
pointer to opened stream object |
|
); |
|
Parameters
pwcsName
[in] Points
to a wide character string that contains the name of the stream to open.
reserved1
[in] Reserved
for future use; must be 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; must be zero.
ppstm
[out] On
successful return, points to the location of an IStream pointer to the
newly-opened stream object. This parameter is set to NULL if an error occurs.
Return Values
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 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.
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.
See Also