FilterGetInformation function (fltuser.h)

Article
10/13/2021

The FilterGetInformation function returns various kinds of information about a minifilter.

Syntax

HRESULT FilterGetInformation(
  [in]  HFILTER                  hFilter,
  [in]  FILTER_INFORMATION_CLASS dwInformationClass,
  [out] LPVOID                   lpBuffer,
  [in]  DWORD                    dwBufferSize,
  [out] LPDWORD                  lpBytesReturned
);

Parameters

[in] hFilter

Handle returned by a previous call to the FilterCreate function.

[in] dwInformationClass

Type of information requested. This parameter must be one of the following values.

Value	Meaning
FilterFullInformation	Return a FILTER_FULL_INFORMATION structure for the minifilter.
FilterAggregateBasicInformation	Return a FILTER_AGGREGATE_BASIC_INFORMATION structure for the minifilter. This dwInformationClass value is available starting with Microsoft Windows Server 2003 with SP1 and Microsoft Windows XP with SP2 with filter manager rollup. For more information about the filter manager rollup package for Windows XP with SP2, see article 914882, " The filter manager rollup package for Windows XP SP2," in the Microsoft Knowledge Base.
FilterAggregateStandardInformation	Return a FILTER_AGGREGATE_STANDARD_INFORMATION structure for each minifilter. The LegacyFilter portion of the structure is not utilized. This dwInformationClass value is available starting with Windows Vista.

[out] lpBuffer

Pointer to a caller-allocated buffer that receives the requested information. The type of the information returned in the buffer is defined by the dwInformationClass parameter.

[in] dwBufferSize

Size, in bytes, of the buffer that the lpBuffer parameter points to. The caller should set this parameter according to the given dwInformationClass.

[out] lpBytesReturned

Pointer to a caller-allocated variable that receives the number of bytes returned in the buffer that lpBuffer points to if the call to FilterGetInformation succeeds. This parameter is required and cannot be NULL.

Return value

FilterGetInformation returns S_OK if successful. Otherwise, it returns an HRESULT error value, such as one of the following:

Return code	Description
HRESULT_FROM_WIN32(ERROR_INSUFFICIENT_BUFFER)	The buffer pointed to by lpBuffer is not large enough to contain the requested information. When this value is returned, lpBytesReturned will contain the size, in bytes, of the buffer required for the given dwInformationClass structure.
HRESULT_FROM_WIN32(ERROR_INVALID_PARAMETER)	An invalid value was specified for the dwInformationClass parameter. For example, if FilterAggregateStandardInformation is specified for an operating system prior to Windows Vista, FilterGetInformation returns this HRESULT value.

Remarks

FilterGetInformation is the Win32 equivalent of FltGetFilterInformation.

Requirements

Requirement	Value
Target Platform	Universal
Header	fltuser.h (include FltUser.h)
Library	FltLib.lib
DLL	FltLib.dll