[This is preliminary documentation and subject to change.]
SCODE IFilter::GetValue( PROPVARIANT ** ppPropValue );
GetValue is the analog to GetText for non-textual attribute values. GetValue should only be called once per chunk. Any additional calls to GetValue should return FILTER_E_NO_MORE_VALUES until GetChunk has been called successfully, advancing to the next chunk.
Indirect values must be allocated with CoTaskMemAlloc. They are owned by the caller of GetValue, who must free them with CoTaskMemFree.
If the current chunk does not have a flags value of CHUNK_VALUE then the error FILTER_E_NO_VALUES is returned. The effect of publishing the same value from more than 1 chunk is undefined.