FltGetStreamContext function (fltkernel.h)
The FltGetStreamContext routine retrieves a context that was set for a file stream by a given minifilter driver instance.
Syntax
NTSTATUS FLTAPI FltGetStreamContext(
[in] PFLT_INSTANCE Instance,
[in] PFILE_OBJECT FileObject,
[out] PFLT_CONTEXT *Context
);
Parameters
[in] Instance
Opaque instance pointer for the minifilter driver instance whose context is to be retrieved.
[in] FileObject
Pointer to a file object for the stream.
[out] Context
Pointer to a caller-allocated variable that receives the address of the context. This parameter is required and can't be set to NULL.
Return value
FltGetStreamContext returns STATUS_SUCCESS when it successfully returns the requested context. Otherwise, it returns an appropriate NTSTATUS value such as one of the following:
| Return code | Description |
|---|---|
| STATUS_NOT_FOUND | No matching context was found on this file at this time, so FltMgr set Context to NULL_CONTEXT. This is an error code. |
| STATUS_NOT_SUPPORTED | The file system does not support per-stream contexts for this file stream. This is an error code. |
Remarks
For more information about contexts, see About minifilter contexts.
FltGetStreamContext retrieves a context that was set for a file stream by a given minifilter driver instance.
FltGetStreamContext increments the reference count on the context that the Context parameter points to. When this context pointer is no longer needed, the caller must decrement its reference count by calling FltReleaseContext. Thus every successful call to FltGetStreamContext must be matched by a subsequent call to FltReleaseContext.
To set a context for a file stream, call FltSetStreamContext.
To allocate a new context, call FltAllocateContext.
To delete a stream context, call FltDeleteStreamContext or FltDeleteContext.
Requirements
| Requirement | Value |
|---|---|
| Target Platform | Universal |
| Header | fltkernel.h (include Fltkernel.h) |
| Library | FltMgr.lib |
| DLL | Fltmgr.sys |
| IRQL | <= APC_LEVEL |