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FILTER_MESSAGE_HEADER structure (fltuserstructures.h)

  • Article

The FILTER_MESSAGE_HEADER structure contains message header information.

Syntax

typedef struct _FILTER_MESSAGE_HEADER {
  ULONG     ReplyLength;
  ULONGLONG MessageId;
} FILTER_MESSAGE_HEADER, *PFILTER_MESSAGE_HEADER;

Members

ReplyLength

On output from FilterGetMessage, this field receives the length, in bytes, of the expected reply, including the FILTER_REPLY_HEADER header. Set to zero if no reply is expected.

MessageId

On output from FilterGetMessage, this field receives the unique identifier (ID) for the message sent by the kernel-mode driver. If the application replies to the message, it must set this ID in the MessageId field of the FILTER_REPLY_HEADER header in the reply.

Remarks

To receive messages from a kernel-mode minifilter, a user-mode application typically defines a custom message structure. This structure typically consists of this header structure, followed by an application-defined structure to hold the actual message data.

Requirements

Requirement Value
Header fltuserstructures.h (include FltUser.h, Fltkernel.h)

See also

FILTER_REPLY_HEADER

FilterGetMessage