IFilter::GetValue Method

Retrieves a value (internal value-type property) from a chunk, which must have a CHUNKSTATE enumeration value of CHUNK_VALUE.

Syntax

SCODE GetValue(      
    PROPVARIANT **ppPropValue
);

Parameters

  • ppPropValue
    [out] Pointer to an output variable that receives a pointer to the PROPVARIANT structure that contains the value-type property.

Return Value

Returns one of the following values.

S_OK Successful completion.
FILTER_E_NO_MORE_VALUES The GetValue method has already been called on this chunk; this value should be returned until the IFilter::GetChunk method has been called successfully and has advanced to the next chunk.
FILTER_E_NO_VALUES The current chunk does not have a CHUNKSTATE enumeration value of CHUNK_VALUE.

Remarks

Call the GetValue method only once per chunk.

Note that the effect of producing the same value from more than one chunk is undefined. Only the last setting of the value is valid.

Notes to Callers

Allocate the PROPVARIANT structure with CoTaskMemAlloc. Some PROPVARIANT structures contain pointers, which can be freed by calling the PropVariantClear function. It is up to the caller of the GetValue method to call the PropVariantClear method.

See Also

CHUNKSTATE, CoTaskMemAlloc, IFilter, IFilter::GetChunk, IFilter::GetText, PROPVARIANT, PropVariantClear, Secure Code Practices, STAT_CHUNK