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FltDeleteStreamHandleContext function

FltDeleteStreamHandleContext removes a context that a given minifilter driver instance has set for a given stream handle and marks the context for deletion.

Syntax


NTSTATUS FltDeleteStreamHandleContext(
  _In_   PFLT_INSTANCE Instance,
  _In_   PFILE_OBJECT FileObject,
  _Out_  PFLT_CONTEXT *OldContext
);

Parameters

Instance [in]

Opaque instance pointer for the minifilter driver instance whose context is to be removed from the list of contexts attached to the stream handle.

FileObject [in]

Pointer to a file object for the file stream.

OldContext [out]

Pointer to a caller-allocated variable that receives the address of the deleted context. This parameter is optional and can be NULL. If OldContext is not NULL and does not point to NULL_CONTEXT, the caller is responsible for calling FltReleaseContext to release this context when it is no longer needed.

Return value

FltDeleteStreamHandleContext returns STATUS_SUCCESS or an appropriate NTSTATUS value such as one of the following:

Return codeDescription
STATUS_FLT_DELETING_OBJECT

The specified Instance is being torn down. This is an error code.

STATUS_NOT_FOUND

No matching context was found. 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

Because contexts are reference-counted, it is not usually necessary for a minifilter driver to call a routine such as FltDeleteStreamHandleContext to explicitly delete a context.

A minifilter driver calls FltDeleteStreamHandleContext to remove a context from a stream handle and mark the context for deletion. The context is usually freed immediately unless there is an outstanding reference on it (for example, because the context is still in use by another thread).

To allocate a new context, call FltAllocateContext.

To get a stream handle context, call FltGetStreamHandleContext.

To set a stream handle context, call FltSetStreamHandleContext.

Requirements

Header

Fltkernel.h (include Fltkernel.h)

Library

FltMgr.lib

IRQL

<= APC_LEVEL

See also

FltAllocateContext
FltDeleteContext
FltGetStreamHandleContext
FltReleaseContext
FltSetStreamHandleContext

 

 

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