FsRtlLookupPerStreamContext macro (ntifs.h)
The FsRtlLookupPerStreamContext macro retrieves a per-stream context structure for a file stream.
Syntax
void FsRtlLookupPerStreamContext(
_sc,
_oid,
_iid
);
Parameters
_sc
Pointer to the FSRTL_ADVANCED_FCB_HEADER structure for the file stream. To get this pointer from a file object, use the FsRtlGetPerStreamContextPointer macro.
_oid
Pointer to a caller-allocated variable that uniquely identifies the owner of the per-stream context structure. The format of this variable is filter driver − specific. Must be non-NULL if a non-NULL value is supplied for InstanceId.
_iid
Pointer to a filter driver − allocated variable that can be used to distinguish among per-stream context structures created by the same filter driver. The format of this variable is filter driver − specific.
If OwnerId and InstanceId are both NULL, FsRtlLookupPerStreamContext returns the first per-stream context found.
If a non-NULL value is supplied for OwnerId and InstanceId is NULL, FsRtlLookupPerStreamContext returns the first per-stream context found whose OwnerId member matches the OwnerId parameter.
Return value
None
Remarks
A file system filter driver calls FsRtlLookupPerStreamContext to retrieve its per-stream context structure for a file stream. The per-stream context structure contains context information that the filter driver maintains for the file stream.
To associate an initialized per-stream context structure with a file stream, call FsRtlInsertPerStreamContext.
To remove a per-stream context structure that is associated with a file stream, call FsRtlRemovePerStreamContext.
For more information, see Tracking Per-Stream Context in a Legacy File System Filter Driver.
Requirements
| Requirement | Value |
|---|---|
| Minimum supported client | Windows 2000 SP4 Update Rollup; Windows XP |
| Target Platform | Desktop |
| Header | ntifs.h (include Ntifs.h) |
| Library | NtosKrnl.lib |
| DLL | NtosKrnl.exe |
| IRQL | <= APC_LEVEL |
See also
FsRtlGetPerStreamContextPointer