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FILTER_AGGREGATE_STANDARD_INFORMATION structure (fltuserstructures.h)

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The FILTER_AGGREGATE_STANDARD_INFORMATION structure contains information about a minifilter or legacy filter driver.

Syntax

typedef struct _FILTER_AGGREGATE_STANDARD_INFORMATION {
  ULONG NextEntryOffset;
  ULONG Flags;
  union {
    struct {
      ULONG  Flags;
      ULONG  FrameID;
      ULONG  NumberOfInstances;
      USHORT FilterNameLength;
      USHORT FilterNameBufferOffset;
      USHORT FilterAltitudeLength;
      USHORT FilterAltitudeBufferOffset;
    } MiniFilter;
    struct {
      ULONG  Flags;
      USHORT FilterNameLength;
      USHORT FilterNameBufferOffset;
      USHORT FilterAltitudeLength;
      USHORT FilterAltitudeBufferOffset;
    } LegacyFilter;
  } Type;
} FILTER_AGGREGATE_STANDARD_INFORMATION, *PFILTER_AGGREGATE_STANDARD_INFORMATION;

Members

NextEntryOffset

Byte offset of the next FILTER_AGGREGATE_STANDARD_INFORMATION entry, if multiple entries are present in a buffer. This member is zero if no other entries follow this one.

Flags

Indicates whether the filter driver is a legacy filter or a minifilter. This member must be one of the following values.

Flag Meaning
FLTFL_ASI_IS_MINIFILTER The filter is a minifilter - use the MiniFilter portion of the union.
FLTFL_ASI_IS_LEGACYFILTER The filter is a legacy filter - use the LegacyFilter portion of the union.

Type

Type.MiniFilter

Nested structure variable with the following members:

Type.MiniFilter.Flags

There are currently no flags defined for this member.

Type.MiniFilter.FrameID

Zero-based index used to identify the filter manager frame that the minifilter is in.

Type.MiniFilter.NumberOfInstances

Number of instances that currently exist for the minifilter.

Type.MiniFilter.FilterNameLength

Length, in bytes, of the minifilter name string.

Type.MiniFilter.FilterNameBufferOffset

Byte offset (relative to the beginning of the structure) of the first character of the Unicode minifilter name string. The string is not NULL-terminated.

Type.MiniFilter.FilterAltitudeLength

Length, in bytes, of the minifilter altitude string.

Type.MiniFilter.FilterAltitudeBufferOffset

Byte offset (relative to the beginning of the structure) of the first character of the Unicode minifilter altitude string. The string is not NULL-terminated.

Type.LegacyFilter

Nested structure variable with the following members:

Type.LegacyFilter.Flags

There are currently no flags defined for this member.

Type.LegacyFilter.FilterNameLength

Length, in bytes, of the legacy filter name string.

Type.LegacyFilter.FilterNameBufferOffset

Byte offset (relative to the beginning of the structure) of the first character of the Unicode legacy filter name string. The string is not NULL-terminated.

Type.LegacyFilter.FilterAltitudeLength

Length, in bytes, of the legacy filter altitude string.

Type.LegacyFilter.FilterAltitudeBufferOffset

Byte offset (relative to the beginning of the structure) of the first character of the Unicode legacy filter altitude string. The string is not NULL-terminated.

Starting with Windows Vista, altitudes are assigned to legacy filter drivers based on the driver's load order group. This ensures that minifilter drivers will layer properly above and below legacy filter drivers even if one or more of the filter drivers are loaded out-of-order.

Remarks

The FILTER_AGGREGATE_STANDARD_INFORMATION structure can be allocated from paged or nonpaged pool. This structure is passed as a parameter to routines such as:

The FILTER_AGGREGATE_STANDARD_INFORMATION structure must be aligned on a LONGLONG (8-byte) boundary. If a buffer contains two or more of these structures, the NextEntryOffset value in each entry falls on an 8-byte boundary.

Requirements

Requirement Value
Minimum supported client This structure is available starting with Windows Vista.
Header fltuserstructures.h (include FltUser.h, FltKernel.h)

See also

FILTER_AGGREGATE_BASIC_INFORMATION

FILTER_FULL_INFORMATION

FilterFindFirst

FilterFindNext

FilterGetInformation

FltEnumerateFilterInformation

FltGetFilterInformation