FilterInstanceGetInformation function (fltuser.h)

Article
10/13/2021

The FilterInstanceGetInformation function returns various kinds of information about a minifilter instance.

Syntax

HRESULT FilterInstanceGetInformation(
  [in]  HFILTER_INSTANCE           hInstance,
  [in]  INSTANCE_INFORMATION_CLASS dwInformationClass,
  [out] LPVOID                     lpBuffer,
  [in]  DWORD                      dwBufferSize,
  [out] LPDWORD                    lpBytesReturned
);

Parameters

[in] hInstance

Handle returned by a previous call to FilterInstanceCreate.

[in] dwInformationClass

The type of instance information structure returned. This parameter must contain one of the following values.

Value	Meaning
InstanceBasicInformation	Return an INSTANCE_BASIC_INFORMATION structure for the instance.
InstanceFullInformation	Return an INSTANCE_FULL_INFORMATION structure for the instance.
InstancePartialInformation	Return an INSTANCE_PARTIAL_INFORMATION structure for the instance.
InstanceAggregateStandardInformation	Return an INSTANCE_AGGREGATE_STANDARD_INFORMATION structure for the instance. The LegacyFilter portion of the structure is utilized starting with Windows 8. This structure 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 FilterInstanceGetInformation succeeds. This parameter is required and cannot be NULL.

Return value

FilterInstanceGetInformation 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 InstanceAggregateStandardInformation is specified for an operating system prior to Windows Vista, FilterInstanceGetInformation returns this HRESULT value.

Remarks

Given a handle to a minifilter instance, this routine returns information about the minifilter instance. The type of instance information returned is determined by the dwInformationClass parameter.

FilterInstanceGetInformation is the Win32 equivalent of FltGetInstanceInformation.

Requirements

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